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    Ccna security prep from networkers Ccna security prep from networkers Document Transcript

    • BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 1 CCNA Security: A New Associate Level Career Path Option BRKCRT-1104 BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 2© 2006, Cisco Systems, Inc. All rights reserved. 1Presentation_ID.scr
    • Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 3 Goals of This Session What this session will not be: A replacement to the 5 day IINS course An exam cram session focusing on the content of the IINS exam An exact match to the content of the IINS course What this session will include: A discussion of security issues and technology relevant to those pursuing a career in Network Security at the associate level A presentation based on, but not limited by, the concepts covered in the IINS class A demonstration of attack methodologies and mitigation of the attack using Cisco security technology BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 4© 2006, Cisco Systems, Inc. All rights reserved. 2Presentation_ID.scr
    • Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 5 Disclaimer Do not repeat the exercises demonstrated during this presentation on any network for which you do not have complete authorization to do so. The demonstrations are carried out on an isolated network within the Global Knowledge remote labs environment. Practicing similar exercises outside of this environment requires many considerations including, but not limited to: 1. Many organizations have security policies explicitly forbidding the use of these types of tools on the their networks. Job termination and/or criminal prosecution may be the penalty. 2. Often these types of tools are distributed with hidden malware. By installing such tools you may unknowingly also be installing keystroke loggers, back doors, or other types of malware. 3. Use of these types of tools with targets that are owned by other entities may violate local, state and/or federal laws. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 6© 2006, Cisco Systems, Inc. All rights reserved. 3Presentation_ID.scr
    • Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 7 Changing Threats and Challenges Where Can I Get Attached? Operating System Network Services Applications Users Attack Attack Anywhere Everywhere BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 8© 2006, Cisco Systems, Inc. All rights reserved. 4Presentation_ID.scr
    • The Morris Worm Recognized as the first Internet Worm Written by Robert Tappan Morris Released on November 2, 1988 Two target OS’s: BSD on DEC VAX and SunOS Intent was to gauge the size of the Internet Could (and did) infect same system multiple times, hence ended up being a crippling issue The worm consisted of an executable file (usr/tmp/sh) created from a C program (x$$,l1.c) and one of two object files (x$$,vax.o and x$$,sun3.o) It used 3 vectors: sendmail, fingerd, rsh/rexec BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 9 The Morris Worm Sendmail: Invoked debug mode Used RCPT TO: and requested data be piped to a shell The data was a shell script which created a .c file, which it compiled with the victim’s own C compiler New executable copied the object files from attacking host, determined host OS, and compiled usr/tmp/sh using the appropriate object file BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 10© 2006, Cisco Systems, Inc. All rights reserved. 5Presentation_ID.scr
    • The Morris Worm fingerd & rsh/rexec Differed from sendmail vector in method of transfering files fingerd Buffer overflow–fingerd expected a max of 512 bytes of input, but didn’t verify Vulnerability in both target OS, but exploit was only written to BSD on the DEC VAX rsh/rexec Checked the local .rhosts and /etc/hosts.equiv files for trust relationships Needed to crack username/password Tried common combinations for the password, such as username, first name, last name and last name + firstname. If those attempts failed, it used /usr/dict/words and tried every word in the dictionary BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 11 The Morris Worm Hiding itself: Hid itself from the ps command Unlinked its files so they wouldn’t show up with the ls command Scanning for other hosts: Sequential addresses in local network netstat –r –n /etc/hosts ypcat hosts BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 12© 2006, Cisco Systems, Inc. All rights reserved. 6Presentation_ID.scr
    • The Morris Worm The Main Point: If the very first internet worm was this clever, imagine how clever the they’ve become over the last 20 years! Multiple vectors Dictionary cracking Using local resources (C compiler, dictionary file) Evasion of detection Intelligent location of other networks Attackers think outside the box. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 13 Smurf Attack Attacker 200.1.1.1 ICMP ECHO Replies Target ICMP ECHO SRC=200.1.1.1 DST=171.1.255.255 171.1.0.0/16 Intermediaries ICMP flooding attacks are popular due to amplification techniques: Smurf attacks use a spoofed broadcast ping to elicit a large number of responses to the target. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 14© 2006, Cisco Systems, Inc. All rights reserved. 7Presentation_ID.scr
    • Ping Sweeps and Port Scans Ping sweeps and port scans can attempt to: Identify all services on the network Identify all hosts and devices on the network Identify the operating systems on the network Identify vulnerabilities on the network BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 15 One of the Sneakier Scan Methods: Idle Scanning Attacker Zombie 1) IPID Probe TCP SYN ACK Packet Response: IPID = n TCP RST Packet Target is not listening on Scan Port Target is listening on Scan Port OR Attacker Target Attacker Target TCP SYN to Scan Port TCP SYN to Scan Port Spoof “from” Zombie Spoof “from” Zombie SYN 2) SYN e to cket pons e to Packet Res YN ACK ket pons a S Pac Res RST P TCP TCP RST +1 TCP ID = n IP Zombie doesn’t respond to Zombie the RST, IPID is unchanged Zombie Attacker Zombie Attacker Zombie 3) IPID Probe TCP SYN ACK Packet IPID Probe TCP SYN ACK Packet Response: IPID = n+1 Response: IPID = n+2 TCP RST Packet TCP RST Packet BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 16© 2006, Cisco Systems, Inc. All rights reserved. 8Presentation_ID.scr
    • Demonstration Topology .2 .1 150.150.1.0/24 Perimeter (10) Outside-PC Router 100.100.1.0/30 .1 2K 150.150.1.20 time.nist.gov pc.outside.net .1 192.43.244.18 DMZ Subnet (2) (11) 172.16.1.0/24 Outside Perimeter INTERNET 50.50.50.0/24 200.200.1.0/24 .2 .1 2K3 2K 200.200.20.2 200.200.30.2 .1 IOS-FW Services-R-Us DMZ-Srv (3) (16) 50.50.50.50 172.16.1.15 .1 NAT: 200.200.1.15 .1 www.sru.com .1 www.gkl.com 10.10.0.0/24 10.20.20.0/24 Inside Perimeter (13) (4) Security-Srv .2 XP 2K3 10.10.2.10 L3-Switch .1 Site1-PC .1 10.20.20.10 .1 Management Subnet(6) 10.10.10.0/24 10.30.30.0/24 10.10.2.0/24 End User Subnet (15) (7) 10.10.1.0/24 BackTrack2 Data Center Subnet (5) BT2 XP XP XP (location & IP Varies) 2K3 Site2-PC Admin-PC User-PC 10.30.30.10 10.10.10.10 10.10.10.20 Data-Srv 10.10.1.10 Global Knowledge: Cisco Security Remote Labs BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 17 Demo: Idle Scan Using Nmap Use Nmap to run an idle scan (-sI) with 50.50.50.50 as the zombie host. All of the scan activity appears to be coming from 50.50.50.50 BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 18© 2006, Cisco Systems, Inc. All rights reserved. 9Presentation_ID.scr
    • Man-in-the-Middle Attacks Example: ARP Cache Poisoning 1. IP 10.1.1.2 2. Legitimate ARP reply ? MAC for 10.1.1.1 10.1.1.1 = MAC B.B.B.B IP 10.1.1.2 MAC A.A.A.A A A B IP 10.1.1.1 B C MAC B.B.B.B ARP Table in Host B ARP Table in Host A 10.1.1.2 = MAC C.C.C.C 10.1.1.1 = MAC C.C.C.C 3. Subsequent gratuitous ARP IP 10.1.1.3 replies overwrite legitimate replies C MAC C.C.C.C 10.1.1.1 bound to C.C.C.C Attacker 10.1.1.2 bound to C.C.C.C ARP Table in Host C 10.1.1.1 = MAC B.B.B.B A = host A B = host B 10.1.1.2 = MAC A.A.A.A C = host C BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 19 Demo: ARP Cache Poison Using Cain Cain is a MITM between 10.10.10.20 and it’s default gateway. It has captured 2 FTP credential sets (displayed) as well as 4 Telnet credential sets. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 20© 2006, Cisco Systems, Inc. All rights reserved. 10Presentation_ID.scr
    • How Difficult Is It to Obtain Tools? www.sectools.org www.remote-exploit.org BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 21 Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 22© 2006, Cisco Systems, Inc. All rights reserved. 11Presentation_ID.scr
    • Network Security Is a System Firewall + AV ≠ Network Security Network security is not something you can just buy Technology will assist Policy, Operations, and Design are more important Network security system: A collection of network-connected devices, technologies, and best practices that work in complementary ways to provide security to information assets BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 23 Secure Network Lifecycle Initiation Disposition Acquisition and Development Security Operations and Policy Maintenance Implementation BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 24© 2006, Cisco Systems, Inc. All rights reserved. 12Presentation_ID.scr
    • Security Policy Business Risk Needs Analysis Security Policy Policies, Guidelines, Standards Industry Security Best System Practices Security Operations Incident Response, Monitor and maintenance, Compliance Audit BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 25 Reading List SANS Security Policy Project: http://www.sans.org/resources/policies/ NSA Security Configuration Guides: http://www.nsa.gov/snac/ Cisco Security Design Guides: http://www.cisco.com/go/safe NIST Computer Security Division Publications: http://csrc.nist.gov/publications/PubsSPs.html SP800-14: Generally Accepted Principles and Practices for Securing Information Technology Systems SP800-27a: Engineering Principles for Information Technology Security Wikipedia Security Policy: http://en.wikipedia.org/wiki/Security_policy (follow the See Also links) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 26© 2006, Cisco Systems, Inc. All rights reserved. 13Presentation_ID.scr
    • Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 27 Cryptography: What and Why What: Cryptography: From the greek kryptó (hidden) and gráfo (to write) Cryptology: From the Greek kryptó (hidden) and legein (to speak) Why: Confidentiality, privacy, encryption, Origin Authentication Data Integrity BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 28© 2006, Cisco Systems, Inc. All rights reserved. 14Presentation_ID.scr
    • What Is a Hash Function? Basic requirements for a cryptographic hash function: The input can be any length The output has a fixed length H(x) is relatively easy to compute for any given x H(x) is one-way and not reversible H(x) is collision-free Examples: MD5–128 bit output SHA1–160 bit output BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 29 Hash Example: Update Verification Uses the Concept of a Keyed Hash Sender Receiver Variable-length Shared Received Shared input message secret key message secret key Update Message Update Message Time is X Time is X 1 Hash Hash function function Update Message Time is X 2 4ehIDx67NMop9 4ehIDx67NMop9 4ehIDx67NMop9 Message + hash BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 30© 2006, Cisco Systems, Inc. All rights reserved. 15Presentation_ID.scr
    • Hash Example: Enable Secret router(config)# enable secret password Hashes the password in the router configuration file Uses a strong hashing algorithm based on MD5 Boston(config)# enable secret Curium2006 Boston# show running-config ! Salt Hash hostname Boston Phrase Value ! no logging console enable secret 5 $1$ptCj$vRErS/tehv53JjaqFMzBT/ ! BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 31 Demo: Enable Secret Dictionary Attack Cain used it’s dictionary of 3.5 million words. It took it a couple of minutes to go through the first 2.5 million words, but it found “san-fran” was a match for this enable secret hash BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 32© 2006, Cisco Systems, Inc. All rights reserved. 16Presentation_ID.scr
    • What Is Encryption? Encryption is the conversion of plain text into cipher text using a pre-determined algorithm Generally the cipher text is the same length as the plain text Often a key is used to generate a cipher text from an algorithm for a particular plain text cisco Encrypt !@$!& plaintext ciphertext !@$!& Decrypt cisco ciphertext plaintext BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 33 Symmetric vs. Asymmetric Encryption If the encryption keys used for both encryption and decryption are the same, the keys are said to be symmetric. So, all parties involved must have the same keys When the encryption key used to encrypt is different from the one used to decrypt, the keys are said to be asymmetrical. PKI uses asymmetric keys with the ‘public’ key used for encryption and ‘private’ key for decryption. The two keys are mathematically related but cannot be derived from each other BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 34© 2006, Cisco Systems, Inc. All rights reserved. 17Presentation_ID.scr
    • Symmetric Encryption Algorithms Sender and receiver must share a secret key Usual key length of 40-256 bits DES, 3DES, AES, RC2/4/5/6, IDEA BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 35 Anecdote on Key Length From AES Questions and Answers http://www.nist.gov/public_affairs/releases/aesq&a.htm 16. What is the chance that someone could use the "DES Cracker"- like hardware to crack an AES key? In the late 1990s, specialized "DES Cracker" machines were built that could recover a DES key after a few hours. In other words, by trying possible key values, the hardware could determine which key was used to encrypt a message Assuming that one could build a machine that could recover a DES key in a second (i.e., try 255 keys per second), then it would take that machine approximately 149 thousand-billion (149 trillion) years to crack a 128-bit AES key. To put that into perspective, the universe is believed to be less than 20 billion years old BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 36© 2006, Cisco Systems, Inc. All rights reserved. 18Presentation_ID.scr
    • Asymmetric Encryption Algorithms Use Public/Private key pair: A private key is a key which is only known to the individual who owns it Public key is known to everyone but still belongs to a unique individual Data encrypted using my public key can only be decrypted using my private key (provides confidentiality) Data encrypted using my private key can only be decrypted using my public key (provides authenticity) Usual key length: 360 bit to 4096 bit RSA, DSA BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 37 Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 38© 2006, Cisco Systems, Inc. All rights reserved. 19Presentation_ID.scr
    • What Is AAA ? AAA provides a method to control and configure these three independent security functions: Authentication—Provides the method of identifying users and who are allowed for access. It includes traditional username and password dialog and more secure methods (like CHAP and OTP) Authorization—Provides a method for controlling which services or devices the authenticated user has access to. Accounting—Provides the method for collecting and sending security server information used for billing, auditing, and reporting. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 39 Implementing AAA Using the Local Database: Usernames defined in the configuration Privilege levels defined in the configuration Role-Based CLI defined in the configuration Using an AAA Server: RADIUS —Remote Authentication Dial In User Service TACACS+—Terminal Access Controller Access Control System BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 40© 2006, Cisco Systems, Inc. All rights reserved. 20Presentation_ID.scr
    • RADIUS vs. TACACS+ RADIUS TACACS+ RADIUS uses UDP TACACS+ uses TCP RADIUS encrypts only the password TACACS+ encrypts the entire body of in the access-request packet the packet; more secure RADIUS combines authentication and TACACS+ uses the AAA architecture, authorization; accounting is separate which separates authentication, RADIUS is the industry standard authorization and accounting (created by Livingston) Cisco developed; submitted to IETF, RADIUS does not support ARA but declined access, NetBIOS Frame Protocol TACACS+ offers multiprotocol Control protocol, NASI and X.25 PAD support. connections TACACS+ provides authorization RADIUS does not allow users to control of router commands control which commands can be executed on a router. Requires use of privilege levels or CLI View RADIUS is recommended as the TACACS+ is recommended as the protocol suitable for controlling the protocol suitable for controlling access of users/employees to the administrative access by IT staff to Cisco network. devices themselves. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 41 Cisco Secure ACS Local or TACACS+ Variety of External RADIUS Databases AAA Client (Network Access Server) Cisco Secure ACS for Windows (IINS class uses ACS v4.1) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 42© 2006, Cisco Systems, Inc. All rights reserved. 21Presentation_ID.scr
    • AAA Router CLI Config Example aaa new-model ! aaa authentication login default group tacacs+ local aaa authentication login TACACS_ONLY group tacacs+ aaa authorization exec default group tacacs+ local aaa authorization commands 1 default group tacacs+ local aaa authorization commands 15 default group tacacs+ local aaa accounting exec start-stop tacacs+ aaa accounting network start-stop tacacs+ ! tacacs-server host 10.0.1.11 key Secretf0rAcs ! line vty 0 4 login authentication TACACS_ONLY BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 43 AAA Adding TACACS+ Server Using SDM BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 44© 2006, Cisco Systems, Inc. All rights reserved. 22Presentation_ID.scr
    • AAA Login Authentication Method List BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 45 AAA ACS—Adding the AAA Client (Router) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 46© 2006, Cisco Systems, Inc. All rights reserved. 23Presentation_ID.scr
    • AAA ACS—Groups and Users BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 47 Cisco IOS Command Authorization Using ACS Example Permitting the group to execute any routers commands except the show running-config command: Any IOS commands not matching the show command will be permitted AND Within the show command, only deny the show running-config command, all other show commands arguments are permitted Group Setup router(config)#aaa authorization exec default group tacacs+ BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 48© 2006, Cisco Systems, Inc. All rights reserved. 24Presentation_ID.scr
    • Demo: AAA Using CSACS Authentication: Username and password required for login. Authorization: Specific command sets are assigned to different user groups. Accounting: Commands entered by adminstrators are tracked. Username: netop Password: IOS-FW>en Password: IOS-FW#debug ip packet Command authorization failed. % Incomplete command. IOS-FW#debug snmp packet SNMP packet debugging is on IOS-FW#undebug all All possible debugging has been turned off IOS-FW# BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 49 Secure Remote Administrative Access: SSH—The Secure Shell Protocol SSH v1 SSH v2 Separate Transport, Architecture One Monlithic Protocol Authentication and Connection Protocols Integrity Check Weak CRC-32 Strong HMAC Negotiates algorithms for Security Only negotiates bulk PKI, bulk encryption Negotiation cipher encryption, HMAC Uses server’s public Uses Diffie-Hellman key Session Key key to protect session exchange key provided by client Knowledge of the server’s public key is required for Origin Authentication BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 50© 2006, Cisco Systems, Inc. All rights reserved. 25Presentation_ID.scr
    • Demo: SSH IOS-FW#debug ip ssh Incoming SSH debugging is on IOS-FW# *Apr 4 02:45:30.991: SSH3: starting SSH control process *Apr 4 02:45:30.991: SSH3: sent protocol version id SSH-1.99-Cisco-1.25 *Apr 4 02:45:31.011: SSH3: protocol version id is - SSH-1.5-PuTTY_Release_0.58 *Apr 4 02:45:31.015: SSH3: SSH_SMSG_PUBLIC_KEY msg *Apr 4 02:45:31.019: SSH3: SSH_CMSG_SESSION_KEY msg - length 144, type 0x03 *Apr 4 02:45:31.019: SSH: RSA decrypt started *Apr 4 02:45:31.143: SSH: RSA decrypt finished *Apr 4 02:45:31.143: SSH: RSA decrypt started *Apr 4 02:45:31.207: SSH: RSA decrypt finished *Apr 4 02:45:31.211: SSH3: sending encryption confirmation *Apr 4 02:45:31.211: SSH3: keys exchanged and encryption on *Apr 4 02:45:35.119: SSH3: SSH_CMSG_USER message received *Apr 4 02:45:35.119: SSH3: authentication request for userid admin *Apr 4 02:45:35.127: SSH3: SSH_SMSG_FAILURE message sent *Apr 4 02:45:47.695: SSH3: SSH_CMSG_AUTH_PASSWORD message received *Apr 4 02:45:52.703: SSH3: authentication successful for admin *Apr 4 02:45:52.703: SSH3: requesting TTY *Apr 4 02:45:52.703: SSH3: setting TTY - requested: length 24, width 80; set: length 24, width 80 *Apr 4 02:45:52.707: SSH3: SSH_CMSG_EXEC_SHELL message received *Apr 4 02:45:52.707: SSH3: starting shell for vty BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 51 Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 52© 2006, Cisco Systems, Inc. All rights reserved. 26Presentation_ID.scr
    • What Is a Firewall? A firewall is a system or group of systems that enforce an access control policy between two networks Good Traffic Bad Traffic Three basic classes of firewalls include: Packet Filters Proxy Servers Stateful Firewalls BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 53 Packet Filtering Packet filtering limits packets into a network based on the destination and source addresses, ports, and other flags compiled in an ACL BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 54© 2006, Cisco Systems, Inc. All rights reserved. 27Presentation_ID.scr
    • Packet Filter Limitations They Must Examine Packets in Isolation: access-list 100 remark The following denies RFC 1918 addresses access-list 100 deny ip 10.0.0.0 0.255.255.255 any log access-list 100 deny ip 172.16.0.0 0.15.255.255 any log access-list 100 deny ip 192.168.0.0 0.0.255.255 any log access-list 100 remark The following permits existing TCP connections Checks for ACK or access-list 100 permit tcp any 200.200.1.0 0.0.0.255 established RST, with no knowledge of access-list 100 remark permit DMZ server access previous flow access-list 100 permit tcp any host 200.200.1.15 eq ftp access-list 100 permit tcp any host 200.200.1.15 eq www Is the reply really in response to an access-list 100 remark Allow echo replies to return echo? access-list 100 permit icmp any 200.200.1.0 0.0.0.255 echo-reply Was this really access-list 100 remark Allow FTP data channels requested from inside requested in a access-list 100 permit tcp any eq ftp-data 200.200.1.0 0.0.0.255 valid FTP control channel? access-list 100 remark Allow NTP replies to return from time.nist.gov access-list 100 permit udp host 192.43.244.18 eq ntp any Might someone spoof access-list 100 remark deny and log all else time.nist.gov’s IP access-list 100 deny ip any any log address? BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 55 Application Layer Gateway or Proxy Server BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 56© 2006, Cisco Systems, Inc. All rights reserved. 28Presentation_ID.scr
    • How Classic Stateful Firewall Works 1. ACLs specify policy for new sessions. 2. If the ACLs permit the first packet in the session, a state table entry is created. 3. Sessions in the state table are permitted bidirectionally, as long as the rules of the session protocol are obeyed. 4. Valid dynamic connections that are negotiated in an authorized control channel are also allowed. Examples include FTP, SQL-Net and 192.168.1.1 VoIP applications. Port Port 3575 80 State Inbound ACL Table internet Fa0/0 S0 inside outside 10.0.1.12/24 Inside user initiates a HTTP session to the Attacker Internet. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 57 Application Inspection Firewalls Have features of a stateful firewall Work with NAT Monitor sessions to determine port numbers for secondary channels Engage in deep packet inspection and filtering for some protocols. For example: SMTP commands HTTP commands and tunnels FTP commands Have the following advantages: Are aware of Layer 4 and Layer 5 states Check the conformity of application commands on Layer 5 Can check and affect Layer 7 Can prevent more types of attacks than stateful firewalls BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 58© 2006, Cisco Systems, Inc. All rights reserved. 29Presentation_ID.scr
    • Zone-Based Policy Firewall Private-DMZ Public-DMZ Requests Requests Untrusted DMZ Trusted Internet Default DENY ALL Zone-Based Policy introduces a new firewall configuration model Policies are applied to traffic moving between zones, not interfaces A zone is a collection of interfaces BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 59 Security Zone Pairs not in any security zones E2 S4 E0 Self-Zone S3 Zone Z1 Zone Z2 E1 Security Zone Pair Source = Z1 Destination = Z2 BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 60© 2006, Cisco Systems, Inc. All rights reserved. 30Presentation_ID.scr
    • Zone Rules Summary An interface can be assigned to only one security zone All traffic to and from a given interface is implicitly blocked when the interface is assigned to a zone, except traffic to or from other interfaces in the same zone, and traffic to any interface on the router If two interfaces are not in zones, traffic flows freely between them If one interface is in a zone, and another interface is not in a zone, traffic cannot flow between them If two interfaces are in two different zones, traffic will not flow between the interfaces until a policy is defined to allow that traffic All of the IP interfaces on the router are automatically made part of the “self” zone when zone-based policy firewall is configured By default, traffic to and from the router itself is permitted BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 61 Configure a ZBP Firewall 1. Identify interfaces with similar policy requirements and group them into security zones 2. Determine the required traffic flow between zones in both directions 3. Set up zone pairs for any policy other than deny all 4. Define class-maps to describe traffic between zones 5. Associate class-maps with policy-maps to define actions applied to specific policies 6. Assign policy-maps to zone-pairs BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 62© 2006, Cisco Systems, Inc. All rights reserved. 31Presentation_ID.scr
    • Security Zone Firewall Configuration CPL–Cisco Policy Language (CPL) Class-Map (used to select traffic for inspection policies) Policy-Map (used to apply policy to traffic class) (e.g. inspect/pass/drop policy) Service-Policy - Apply policy-map to zone pair (used to activate the inspection policy) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 63 ZBP Policy Actions Inspect Monitor outbound traffic according to permit/deny policy Anticipate return traffic according to session table entries Drop Analogous to deny Pass Analogous to permit No stateful capability BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 64© 2006, Cisco Systems, Inc. All rights reserved. 32Presentation_ID.scr
    • SDM Zone Based Firewall Wizard BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 65 Zone-Based Policy Firewall Configuration Example class-map type inspect match-any myprotocols match protocol http Define the list of match protocol smtp services in the firewall match protocol dns policy ! policy-map type inspect myfwpolicy class type inspect myprotocols inspect Apply action (inspect = ! stateful inspection) zone security private zone security public ! Configure Zones interface fastethernet 0/0 zone-member security private Assign Interfaces to ! interface fastethernet 0/1 Zones zone-member security public ! Apply inspection from zone-pair security priv-to-pub source private destination public service-policy type inspect myfwpolicy private to public zones ! BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 66© 2006, Cisco Systems, Inc. All rights reserved. 33Presentation_ID.scr
    • Demo–Packet Filter and Zone Based Firewall 1) No Access-Control: A simple ping sweep using ICMP Echo finds everything, including dynamic NAT systems BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 67 Demo–Packet Filter and Zone Based Firewall 2) Packet Filter permitting all TCP established packets and ICMP echo to 200.200.1.15: Simple ping sweep using ICMP Echo only finds 200.200.1.15 BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 68© 2006, Cisco Systems, Inc. All rights reserved. 34Presentation_ID.scr
    • Demo–Packet Filter and Zone Based Firewall 2.5) Packet Filter permitting TCP established and ICMP echo to 200.200.1.15: But, a “ping” sweep using TCP ACKs still finds everything! BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 69 Demo–Packet Filter and Zone Based Firewall 3) Turn on Stateful Firewalling: TCP ACK ping can no longer find hosts behind firewall BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 70© 2006, Cisco Systems, Inc. All rights reserved. 35Presentation_ID.scr
    • Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 71 The Problem Site A Internet Site B The hosts on the Site A and Site B networks use legacy, insecure protocols such as SMTP, POP, HTTP and Telnet This is OK for intra-site communications on the protected internal networks It is not acceptable across the Internet Changing the protocols used by the hosts is not an option, so you need the routers to use VPN technology to protect data transmitted between the sites BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 72© 2006, Cisco Systems, Inc. All rights reserved. 36Presentation_ID.scr
    • IPSec Protocol Architecture IPSec Uses IKE for Key Maintenance and ESP and/or AH for Protection of Data Internet Key Exchange (IKE) provides a mechanism to derive keying material and negotiate security associations Encapsulating Security Payload (ESP) provides Confidentiality, Data Integrity and Origin Authentication AH provides Data Integrity and Origin Authentication BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 73 Break Down of IPSec: IKE Hybrid protocol: ISAKMP, Oakley Key exchange, SKEME Defines the mechanism to derive authenticated keying material and negotiate security associations (used for AH, ESP) Uses UDP port 500 Defined in RFC 2409 Internet Key Exchange protocol Negotiates protocol parameters Exchanges public keys (Diffie Hellman - DH) Authenticates both sides Manages keys after exchange BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 74© 2006, Cisco Systems, Inc. All rights reserved. 37Presentation_ID.scr
    • IKE Phases, Security Associations ISAKMP SA Site A Internet Site B IPSec SA IPSec SA Two-Phase protocol: Phase 1 exchange: two peers establish a secure, authenticated channel for IKE communications Main mode or aggressive mode accomplishes a phase 1 exchange Phase 2 exchange: security associations are negotiated on behalf of IPSec services. Quick mode accomplishes a phase II exchange Each phase has its SAs: ISAKMP SA (Phase 1) and IPSec SA (Phase 2) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 75 IKE Authentication Methods Pre-shared key Easy to deploy, not scalable Public-key signatures (rsa-signature) Most secure, requires PKI. Public-key encryption (rsa-nonce) Similar security to rsa-sig, requires prior knowledge of peer’s public key, limited support on Cisco hardware ISR(config)# crypto isakmp policy 1001 ISR(config-isakmp)# authentication ? pre-share Pre-Shared Key rsa-encr Rivest-Shamir-Adleman Encryption rsa-sig Rivest-Shamir-Adleman Signature BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 76© 2006, Cisco Systems, Inc. All rights reserved. 38Presentation_ID.scr
    • DH Exchange Private Value, XA Private Value, XB Alice Public Value, YA Public Value, YB Bob XA XB YA =g mod p YB = g mod p YA YB XB XA YB mod p = zz YA mod p = zz (Alice calculated) (Bob calculated) XA XB zz = shared secret = g mod p BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 77 Encapsulating Security Payload (ESP) DES 3DES Data confidentiality AES SEAL HMAC-MD5 Data integrity (does not cover ip header) HMAC-SHA Only the IKE authenticated Data origin authentication peer can use the negotiated keys Sequence no. Anti-replay detection & Sliding window Use IP protocol 50 Defined in RFC 2406 ISR(config)#crypto ipsec transform-set test ? ah-md5-hmac AH-HMAC-MD5 transform ah-sha-hmac AH-HMAC-SHA transform comp-lzs IP Compression using the LZS compression algorithm esp-3des ESP transform using 3DES(EDE) cipher (168 bits) esp-aes ESP transform using AES cipher esp-des ESP transform using DES cipher (56 bits) esp-md5-hmac ESP transform using HMAC-MD5 auth esp-null ESP transform w/o cipher esp-seal ESP transform using SEAL cipher (160 bits) BRKCRT-1104 esp-sha-hmac ESP transform using HMAC-SHA auth 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 78© 2006, Cisco Systems, Inc. All rights reserved. 39Presentation_ID.scr
    • ESP tunnel mode Original IP datagram IP header IP payload New Original ESP header IP payload IP header IP header IP datagram encrypted with ESP Tunnel Integrity checked ESP transport mode Original IP datagram IP header IP payload IP header ESP header IP payload IP datagram encrypted with ESP Transport Integrity checked BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 79 Site-to-Site IPSec VPN Host A Host B RouterA RouterB 10.2.2.3 10.1.1.3 1. Host A sends interesting traffic to Host B. 2. Routers A and B negotiate an IKE Phase 1 session. IKE SA IKE Phase 1 IKE SA 3. Routers A and B negotiate an IKE Phase 2 session. IPSec SA IKE Phase 2 IPSec SA 4. Information is exchanged via IPsec tunnel. IPSec Tunnel 5. The IPsec tunnel is terminated. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 80© 2006, Cisco Systems, Inc. All rights reserved. 40Presentation_ID.scr
    • Site-to-Site IPSec Configuration Step 1: Ensure that access lists are compatible with IPSec Step 2: ISAKMP (IKE) policy Step 3: IPSec transform set Step 4: Cryptographic access list Step 5: Create and apply the cryptographic map BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 81 Introducing the Cisco SDM VPN Wizard Interface 1 Wizards for IPsec 3 Solutions 2 Individual IPsec Components 4 5 1. Enter the configuration page. 2. Choose the VPN page. 3. Choose the desired VPN wizard (VPN type). 4. Choose the VPN implementation subtype. 5. Start the wizard. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 82© 2006, Cisco Systems, Inc. All rights reserved. 41Presentation_ID.scr
    • Quick Setup Configure all parameters on one page BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 83 IPSec Configuration Example Site 1 10.0.1.0 10.0.6.0 Site 2 R1 R6 A Internet B 10.0.1.12 10.0.6.12 172.30.1.2 172.30.6.2 R1# show running-config R6# show running -config crypto isakmp policy 110 crypto isakmp policy 110 encr 3des encr 3des hash md5 hash md5 authentication pre-share authentication pre-share group 2 group 2 lifetime 36000 lifetime 36000 crypto isakmp key cisco1234 address 172.30.6.2 crypto isakmp key cisco1234 address 172.30.1.2 ! ! crypto ipsec transform -set SNRS esp-des crypto ipsec transform -set SNRS esp-des ! ! crypto map SNRS -MAP 10 ipsec-isakmp crypto map SNRS -MAP 10 ipsec-isakmp set peer 172.30.6.2 set peer 172.30.1.2 set transform-set SNRS set transform-set SNRS match address 101 match address 101 ! ! interface Ethernet 0/1 interface Ethernet 0/1 ip address 172.30.1.2 255.255.255.0 ip address 172.30.6.2 255.255.255.0 crypto map SNRS -MAP crypto map SNRS -MAP ! ! access-list 102 permit ip 10.0.1.0 0.0.0.255 access-list 102 permit ip 10.0.6.0 0.0.0.255 10.0.6.0 0.0.0.255 10.0.1.0 0.0.0.255 BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 84© 2006, Cisco Systems, Inc. All rights reserved. 42Presentation_ID.scr
    • Some More Advanced VPN Technologies Public Key Infrastructure (PKI) and Digital Certificates Remote Access VPN Web VPN Dynamic Multipoint VPN (DMVPN) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 85 Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 86© 2006, Cisco Systems, Inc. All rights reserved. 43Presentation_ID.scr
    • IPS Deployment Options Promiscuous Sensor CSA MC CS MARS IOS Firewall Agent Agent Agent with IOS IPS Untrusted Network Inline Sensor Agent Agent Agent Agent SMTP Agent Agent Server Web DNS Server Server BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 87 IDS vs. IPS IDS (promiscuous mode) Analyzes copies of the traffic stream Does not slow network traffic because it is not inline Allows some malicious traffic in since it can’t stop attacks inline IPS (inline mode) Works inline in real time to monitor network traffic and content Needs to be able to handle the network traffic inline Prevents malicious traffic entering the network, since it is inline, it can stop the trigger packet BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 88© 2006, Cisco Systems, Inc. All rights reserved. 44Presentation_ID.scr
    • IPS Attach Responses Deny attacker inline Produce alert Deny connection inline Produce verbose alert Deny packet inline Request block connection Log attacker packets Request block host Log pair packets Request SNMP trap Log victim packets Reset TCP connection BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 89 Support for SDEE and Syslog Network Management Console Alarm SDEE Protocol Alarm Syslog Syslog Server BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 90© 2006, Cisco Systems, Inc. All rights reserved. 45Presentation_ID.scr
    • Signature Micro-Engines Cisco IPS relies on signature micro-engines to support IPS signatures All the signatures in a signature micro-engine are scanned in parallel Each signature micro-engine does the following: Categorizes a group of signatures (and each signature detects patterns of misuse in network traffic) Is customized for the protocol and fields it is designed to inspect Defines a set of legal parameters that have allowable rangers or sets of values Uses router memory to compile, load, and merge signatures BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 91 Cisco IOS IPS Deployment Steps Step 1: Latest Cisco IPS signature package http://www.cisco.com/cgi-bin/tablebuild.pl/ios-v5sigup This package contains a digitally signed signature file that includes all the signatures for entire Cisco IPS product line Step 2: Select one of the two recommended signature categories (list of signatures): IOS-Basic or IOS-Advanced Step 3: Use IOS CLI or SDM 2.4 to customize your signature list: Select additional signatures as desired Delete signatures not relevant to the applications you’re running Tune actions of individual signatures (e.g., add “drop” action) as desired Test your custom signature set in a lab setting before actual deployment BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 92© 2006, Cisco Systems, Inc. All rights reserved. 46Presentation_ID.scr
    • IPS Policies Wizard BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 93 IPS Policies Wizard (Cont.) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 94© 2006, Cisco Systems, Inc. All rights reserved. 47Presentation_ID.scr
    • Configuring Signatures Using Cisco SDM BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 95 Configuring Signatures Using Cisco SDM (Cont.) Signature Alarm Severity Signature Event Actions BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 96© 2006, Cisco Systems, Inc. All rights reserved. 48Presentation_ID.scr
    • Configuring Global Settings BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 97 Configuring Auto Update BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 98© 2006, Cisco Systems, Inc. All rights reserved. 49Presentation_ID.scr
    • Demo–Cisco IOS IPS in Action Deobfuscation: The sensor decodes the URL as an HTTP daemon would. %6F represents the ASCII code for “o” in Hex. The sensor determines that R%6F%6FT.eXe is really an attempt to access root.exe. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 99 Demo–Cisco IOS IPS in Action Metasploit successfully exploits a buffer overflow vulnerability to get a shell prompt on the remote server msf 3com_3cdaemon_ftp_overflow(win32_reverse) > exploit [*] Starting Reverse Handler. [*] Attempting to exploit Windows 2000 English [*] Got connection from 150.150.1.20:4321 <-> 200.200.1.15:1573 Microsoft Windows 2000 [Version 5.00.2195] (C) Copyright 1985-2000 Microsoft Corp. C:Program Files3Com3CDaemon> With IOS IPS enabled, the router detects a suspiciously long user name field in the FTP control stream. The shell connection is not successful, and the event is logged. msf 3com_3cdaemon_ftp_overflow(win32_reverse) > exploit [*] Starting Reverse Handler. [*] Attempting to exploit Windows 2000 English [*] Exiting Reverse Handler. msf 3com_3cdaemon_ftp_overflow(win32_reverse) > BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 100© 2006, Cisco Systems, Inc. All rights reserved. 50Presentation_ID.scr
    • Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 101 Why Be Concerned? If one layer is hacked, communications are compromised without the other layers being aware of the problem. Security is only as strong as your weakest link. When it comes to networking, Layer 2 can be a very weak link. Application Stream Application Application Presentation Presentation Compromised Session Session Transport Protocols and Ports Transport Network IP Addresses Network Data Link Initial Compromise MAC Addresses Data Link Physical Links Physical Physical BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 102© 2006, Cisco Systems, Inc. All rights reserved. 51Presentation_ID.scr
    • MAC Address Concerns Unauthorized MAC addresses MAC Address Spoofing Bridge Table Overflow Attacks MAC A Desired behavior: Port 0/1 allows MAC A 0/1 Port 0/2 allows MAC B Port 0/3 allows MAC C 0/2 0/3 MAC A MAC F MACs 1-1,000,000 Attacker 1 BRKCRT-1104 Attacker 2 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 103 Port Security Configuration Switch(config-if)# switchport mode access switchport port-security switchport port-security maximum value switchport port-security violation {protect | restrict | shutdown} switchport port-security mac-address mac-address switchport port-security mac-address sticky switchport port-security aging {static | time time | type {absolute | inactivity}} BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 104© 2006, Cisco Systems, Inc. All rights reserved. 52Presentation_ID.scr
    • STP Manipulation Root Bridge Priority = 8192 MAC Address= 0000.00C0.1234 F F F B F F F F F B F F ST iority ity DU Pr =0 PB = Pr P BP PD 0 ior ST U Root Bridge Attacker BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 105 BPDU Guard Root Bridge F F F F F B BPDU Guard Enabled STP BPDU Attacker Switch(config)# spanning-tree portfast bpduguard default Globally enables BPDU guard on all ports which have portfast enabled BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 106© 2006, Cisco Systems, Inc. All rights reserved. 53Presentation_ID.scr
    • Root Guard Root Bridge Priority = 0 MAC Address = 0000.0c45.1a5d F F F F Root Guard Enabled F B F STP BPDU Attacker Priority = 0 MAC Address = 0000.0c45.1234 Switch(config-if)# spanning-tree guard root Enables root guard on a per-interface basis BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 107 VLAN Hopping by Rogue Trunk 802.1Q VLAN 10 k Trunk un Tr Q VLAN Server 2.1 20 80 Attacker sees traffic destined for servers Server BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 108© 2006, Cisco Systems, Inc. All rights reserved. 54Presentation_ID.scr
    • VLAN Hopping by Double Tagging The first switch strips 1 off the first tag and sends it back out. 80 20 2. ,10 1Q ,8 Attacker on 02 .1 20 VLAN 10 Q 2 802.1Q, Frame 3 Trunk Fra 4 m e (Native VLAN = 10) Note: This attack works only if the trunk has the same native VLAN as the attacker. Victim The attacker sends double-encapsulated 802.1Q frames. (VLAN 20) The switch performs only one level of decapsulation. Only unidirectional traffic is passed. The attack works even if the trunk ports are set to “off”. Note: There is no way to execute these attacks unless the switch is misconfigured. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 109 Mitigating VLAN Hopping Network Attacks Example 1: If no trunking is required on an interface Switch(config-if)# switchport mode access Configures port as an access port. This disables trunking on the interface. Example 2: If trunking is required Switch(config-if)# switchport mode trunk Switch(config-if)# switchport nonegotiate Enables trunking but prevents DTP frames from being generated. Switch(config-if)# switchport trunk native vlan vlan_number Sets the native VLAN on the trunk to an unused VLAN. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 110© 2006, Cisco Systems, Inc. All rights reserved. 55Presentation_ID.scr
    • ARP Spoofing: Man-in-the-Middle Attacks 1. IP 10.1.1.2 2. Legitimate ARP reply ? MAC for 10.1.1.1 10.1.1.1 = MAC B.B.B.B IP 10.1.1.2 MAC A.A.A.A A A B IP 10.1.1.1 B C MAC B.B.B.B ARP Table in Host B ARP Table in Host A 10.1.1.2 = MAC C.C.C.C 10.1.1.1 = MAC C.C.C.C 3. Subsequent gratuitous ARP IP 10.1.1.3 replies overwrite legitimate replies C MAC C.C.C.C 10.1.1.1 bound to C.C.C.C Attacker 10.1.1.2 bound to C.C.C.C ARP Table in Host C 10.1.1.1 = MAC B.B.B.B A = host A B = host B 10.1.1.2 = MAC A.A.A.A C = host C BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 111 Private VLAN Edge Within a VLAN, layer 2 frames are only allowed between a pair of non-protected ports or a protected port and a non-protected port. Frames are not allowed between a pair of protected ports. L3-Sw#config t Enter configuration commands, one per line. End with CNTL/Z. L3-Sw(config)#interface range fa0/2 - 4 L3-Sw(config-if-range)#switchport protected L3-Sw(config-if-range)#end BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 112© 2006, Cisco Systems, Inc. All rights reserved. 56Presentation_ID.scr
    • Some More Advanced Layer 2 Security Technologies Full-fledged Private VLANs–uses the concept of promiscuous ports and isolated ports and adds the concept of community ports. DHCP Snooping Dynamic ARP Inspection BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 113 Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 114© 2006, Cisco Systems, Inc. All rights reserved. 57Presentation_ID.scr
    • Practice Exam Item 1—SDM-Based Item BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 115 Practice Exam Item 1—(Cont.) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 116© 2006, Cisco Systems, Inc. All rights reserved. 58Presentation_ID.scr
    • Practice Exam Item 1—(Cont.) Based on the zone base firewall SDM configuration windows shown, which statement is correct? A. The “sdm-inspect” policy applies to the bi-direction traffic flow between the in-zone and the out-zone B. All traffic sourced from the in-zone destined to the out-zone to be denied (dropped) C. All traffic sourced from out-zone and destined to the in-zone will be inspected D. The “sdm-inspect” policy classify traffic into four traffic classes (including class-default) BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 117 Practice Exam Item 2—Theory Based Item Encrypting the plaintext using the private key and decrypting the ciphertext using the public key provides which functionality? A. Confidentiality B. Authenticity C. Integrity and Confidentiality D. Confidentiality and Authenticity BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 118© 2006, Cisco Systems, Inc. All rights reserved. 59Presentation_ID.scr
    • Practice Exam Item 3—CLI Configuration Item What additional configuration is required to enable the VTY users to be authenticated using the local database on the router if the ACS server is down? ! username admin privilege 15 secret harDt0CrackPw ! aaa new-model ! aaa authentication login name tacacs+ ! tacacs-server host 10.0.1.1 tacacs-server key Secretf0rAcs ! line vty 0 5 login authentication name ! A. aaa authentication login default tacacs+ local B. aaa authentication login default local C. adding the “local’ option after “aaa authentication login name tacacs+” D. adding the “default’ option after “login authentication name” in the vty config mode BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 119 Practice Exam Item 4—Configuration Related Item What are the two IOS IPS signatures categories based on version 5.x signatures? (Choose two) A. basic B. advanced C. 128MB.sdf D. 256MB.sdf BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 120© 2006, Cisco Systems, Inc. All rights reserved. 60Presentation_ID.scr
    • Practice Exam Item 5—Theory Based Item Which IKE authentication method is the least scalable? A. ACS B. RSA signature C. Pre-shared Key D. AAA E. SHA BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 121 Practice Exam Item 6—Theory Based Item Stateful firewall uses which table to track the connection status? A. ACL table B. Routing table C. State table D. Forwarding table (CEF) E. ARP table BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 122© 2006, Cisco Systems, Inc. All rights reserved. 61Presentation_ID.scr
    • Practice Exam Item 7—SDM Based Item Referring to the IPSec transform set configuration shown, which encryption method is used to provide data confidentiality? A. SHA B. DES C. HMAC D. AES E. ESP BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 123 Practice Exam Item 8—Configuration Related Item When implementing Port Security on Cisco switches, the “sticky MAC address” option will save the secure MAC address to what location? A. ARP table B. MAC address table C. startup configuration D. running configuration E. NVRAM BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 124© 2006, Cisco Systems, Inc. All rights reserved. 62Presentation_ID.scr
    • Practice Exam Item 9—Show Output Related Item ISR#sh policy-map type inspect zone-pair session Zone-pair: in-to-out Service-policy inspect : telnetpolicy Class-map: telnetclass (match-all) Match: protocol telnet Inspect Established Sessions Session 44C831D8 (10.30.30.1:11009)=>(172.26.26.151:23) telnet SIS_OPEN Created 00:01:32, Last heard 00:00:16 Bytes sent (initiator:responder) [52:108] Class-map: class-default (match-any) Match: any Inspect Established Sessions Session 44C82C68 (10.30.30.1:8)=>(172.26.26.151:0) icmp SIS_OPEN Created 00:00:02, Last heard 00:00:00 ECHO request Bytes sent (initiator:responder) [98568:98568] Based on the show output shown, which statement is correct? A. Only telnet traffic will be inspected B. There are two active outbound sessions C. All non-telnet traffic will be dropped D. Host 172.26.26.151 is initiating the telnet session to host 10.30.30.1 BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 125 Practice Exam Item 10—Configuration Related Item aessha esp-sha-hmac esp-sha-hmac 10.1.1.0 0.0.0.255 10.1.2.0 0.0.0.255 10.2.1.0 0.0.0.255 10.0.0.0 0.255.255.255 20 aessha What is wrong regarding the partial S2S IPSec VPN configuration shown? A. The transform-set name does not match between the peers B. The transform-set is missing the AH option C. The transform-set is missing the “mode tunnel” option D. The crypto acl is not a mirror image of the crypto acl on the other peer E. The crypto acl is not matching the 172.16.172.10 and 172.16.171.20 IP address BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 126© 2006, Cisco Systems, Inc. All rights reserved. 63Presentation_ID.scr
    • Agenda Introduction Disclaimer Attack Methodologies Security Policy Cryptography Fundamentals Securing Administrative Access Firewall VPN IPS Layer 2 Security Sample Questions Answer Key BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 127 Practice Exam Item 1 Based on the zone base firewall SDM configuration windows shown, which statement is correct? A. The “sdm-inspect” policy applies to the bi-direction traffic flow between the in-zone and the out-zone B. All traffic sourced from the in-zone destined to the out-zone to be denied (dropped) C. All traffic sourced from out-zone and destined to the in-zone will be inspected D. The “sdm-inspect” policy classify traffic into four traffic classes (including class-default) Correct Answer: D BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 128© 2006, Cisco Systems, Inc. All rights reserved. 64Presentation_ID.scr
    • Practice Exam Item 2 Encrypting the plaintext using the private key and decrypting the ciphertext using the public key provides which functionality? A. Confidentiality B. Authenticity C. Integrity and Confidentiality D. Confidentiality and Authenticity Correct Answer: B BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 129 Practice Exam Item 3 What additional configuration is required to enable the VTY users to be authenticated using the local database on the router if the ACS server is down? ! username admin privilege 15 secret harDt0CrackPw ! aaa new-model ! aaa authentication login name tacacs+ ! tacacs-server host 10.0.1.1 tacacs-server key Secretf0rAcs ! line vty 0 5 login authentication name Correct Answer: C ! A. aaa authentication login default tacacs+ local B. aaa authentication login default local C. adding the “local’ option after “aaa authentication login name tacacs+” D. adding the “default’ option after “login authentication name” in the vty config mode BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 130© 2006, Cisco Systems, Inc. All rights reserved. 65Presentation_ID.scr
    • Practice Exam Item 4 What are the two IOS IPS signatures categories based on version 5.x signatures? (Choose two) A. basic B. advanced C. 128MB.sdf D. 256MB.sdf Correct Answer: A and B BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 131 Practice Exam Item 5 Which IKE authentication method is the least scalable? A. ACS B. RSA signature C. Pre-shared Key D. AAA E. SHA Correct Answer: C BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 132© 2006, Cisco Systems, Inc. All rights reserved. 66Presentation_ID.scr
    • Practice Exam Item 6 Stateful firewall uses which table to track the connection status? A. ACL table B. Routing table C. State table D. Forwarding table (CEF) E. ARP table Correct Answer: C BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 133 Practice Exam Item 7 Referring to the IPSec transform set configuration shown, which encryption method is used to provide data confidentiality? A. SHA B. DES C. HMAC D. AES Correct Answer: D E. ESP BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 134© 2006, Cisco Systems, Inc. All rights reserved. 67Presentation_ID.scr
    • Practice Exam Item 8 When implementing Port Security on Cisco switches, the “sticky MAC address” option will save the secure MAC address to what location? A. ARP table B. MAC address table C. startup configuration D. running configuration E. NVRAM Correct Answer: D BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 135 Practice Exam Item 9—Show Output Related Item ISR#sh policy-map type inspect zone-pair session Zone-pair: in-to-out Service-policy inspect : telnetpolicy Class-map: telnetclass (match-all) Match: protocol telnet Inspect Established Sessions Session 44C831D8 (10.30.30.1:11009)=>(172.26.26.151:23) telnet SIS_OPEN Created 00:01:32, Last heard 00:00:16 Bytes sent (initiator:responder) [52:108] Class-map: class-default (match-any) Match: any Inspect Established Sessions Session 44C82C68 (10.30.30.1:8)=>(172.26.26.151:0) icmp SIS_OPEN Created 00:00:02, Last heard 00:00:00 ECHO request Bytes sent (initiator:responder) [98568:98568] Based on the show output shown, which statement is correct? A. Only telnet traffic will be inspected B. There are two active outbound sessions Correct Answer: B C. All non-telnet traffic will be dropped D. Host 172.26.26.151 is initiating the telnet session to host 10.30.30.1 BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 136© 2006, Cisco Systems, Inc. All rights reserved. 68Presentation_ID.scr
    • Practice Exam Item 10—Configuration Related Item aessha esp-sha-hmac esp-sha-hmac 10.1.1.0 0.0.0.255 10.1.2.0 0.0.0.255 10.2.1.0 0.0.0.255 10.0.0.0 0.255.255.255 20 aessha What is wrong regarding the partial S2S IPSec VPN configuration shown? A. The transform-set name does not match between the peers B. The transform-set is missing the AH option Correct Answer: D C. The transform-set is missing the “mode tunnel” option D. The crypto acl is not a mirror image of the crypto acl on the other peer E. The crypto acl is not matching the 172.16.172.10 and 172.16.171.20 IP address BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 137 Q and A BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 138© 2006, Cisco Systems, Inc. All rights reserved. 69Presentation_ID.scr
    • Recommended Reading Continue your Cisco Live learning experience with further reading from Cisco Press Check the Recommended Reading flyer for suggested books Available Onsite at the Cisco Company Store BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 139 Complete Your Online Session Evaluation Give us your feedback and you could win Don’t forget to activate fabulous prizes. Winners announced daily. your Cisco Live virtual account for access to Receive 20 Passport points for each session all session material evaluation you complete. on-demand and return for our live virtual event Complete your session evaluation online now in October 2008. (open a browser through our wireless network Go to the Collaboration to access our portal) or visit one of the Internet Zone in World of stations throughout the Convention Center. Solutions or visit www.cisco-live.com. BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 140© 2006, Cisco Systems, Inc. All rights reserved. 70Presentation_ID.scr
    • BRKCRT-1104 14381_04_2008_c1 © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 141© 2006, Cisco Systems, Inc. All rights reserved. 71Presentation_ID.scr