Securing Linux systems and applications; understanding Linux security features.
82
votes
8answers
4k views
Attacking an office printer?
I did an nmap scan on an advanced office printer that has a domain name and is accessible from outside the corporate network. Surprisingly I found many open ports like http:80, https:443, and ...
42
votes
8answers
5k views
Hardening Linux Server
We have already had questions on here about Hardening Apache, Hardening PHP and Securing SSH.
To continue this trend I am interested in what steps people take to harden Linux servers. As in what ...
31
votes
2answers
3k views
Is a rand from /dev/urandom secure for a login key?
Lets say I want to cookie for a user, would simply going to /dev/urandom, generating a 1024 bit string, checking if it already exists (and looping till I get a unique one) suffice? Or should I be ...
23
votes
4answers
1k views
Should I change the default SSH port on linux servers?
Is there any advantage in changing the SSH port, I've seen people do that, but I can't seem to find the reason why.
If you have a strong password and/or a certificate, is it useful for anything?
...
22
votes
6answers
2k views
Keeping secrets from root on Linux
I am looking for ways to harden a linux system so that even when gaining full root access (through legit or non-legit means), some secrets remain inaccessible. But first a little background.
Many of ...
19
votes
6answers
2k views
Secure Linux Desktop
I'm looking for hints about secure linux desktops. Securing servers is no problem. Most recent Software Updates, run only the services required etc. But what about desktops? I'm thinking about details ...
18
votes
4answers
3k views
How do you know your server has been compromised?
I recently helped a client who had their server hacked. The hackers added some PHP code into the header of the homepage redirecting the user to a porn website — but only if they came from Google. This ...
15
votes
5answers
1k views
How can I protect my computer from my potentially malicious colleagues?
So, I work in this small company (10 people) where we do stuff in programming, for various platforms. I started recently working there (2 months) right after I graduated. My work is not exactly ...
15
votes
3answers
450 views
If I have two identical linux virtual machine images, will they generate identical random numbers?
A really noob question, I know, but something I was wondering about this morning. If this were the case, would they encrypt things identically?
Or maybe someone could direct me to a helpful research ...
14
votes
2answers
8k views
Simple example auditd configuration?
Auditd was recommended in an answer to Linux command logging?
The default install on Ubuntu seems to barely log anything. There are several examples that come with it (capp.rules, nispom.rules, ...
13
votes
8answers
2k views
Any comprehensive solutions for binary code protection and anti-reverse-engineering?
Does anyone know of good products with comprehensive binary hardening and anti-reverse-engineering features? Or better, has anyone seen an independent review comparing products that perform these ...
13
votes
1answer
494 views
Are there Linux rootkits circulating that directly modify the kernel (without modules)?
It has been said, over and over, that disabling dynamic kernel module loading on Linux increases security. I understand why people give this advice, but I've always assumed that a bad guy could ...
13
votes
1answer
704 views
Did someone really plug an iphone in, or are these symptoms of an exploit attempt?
My syslog indicates that someone plugged an iPhone USB device into my desktop at 4am today, for about 10 minutes. I'm checking physical security logs to see if there was someone in the room, but in ...
12
votes
4answers
324 views
How to safely synchronize time over Internet?
All modern OS now keep accurate time by regularly synchronizing time over an untrusted network - Internet. Could an attacker conducting a MITM attack, influence or change the time of a computer while ...
12
votes
3answers
789 views
Multi factor authentication on Ubuntu workstations, where to start?
Is it possible to have Ubuntu users log in with multi-factor authentication? I was thinking of a combination of pass(word|code) and smartcard (with screen locks when for example smart-card is removed)
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