Securing Linux systems and applications; understanding Linux security features.
42
votes
8answers
6k 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 ...
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 ...
10
votes
8answers
4k views
How anonymous is my setup?
my friend and I are trying to make the most anonymous setup for a computer to do things across the internet without being known the location from which it came.
Our setup is as follows:
A windows ...
5
votes
4answers
3k views
Monitoring system calls (in a reliable and secure way)
It there a reliable method of “monitoring” system calls under Linux?
There is strace for example to monitor system calls and signals. Is there a way for a process to dodge out of strace? If yes, is ...
4
votes
2answers
284 views
What features do you look for in an Enterprise Log Management solution?
This question is for IT Pros, and people who manage a company's infrastructure. Developers should see this related answer for tools geared for them.
What are your requirements for such a Event Log ...
18
votes
0answers
565 views
Where can I find a vulnerable operating system to practice pentests on? [duplicate]
I am looking for vulnerable operating systems that are used for practicing pentests. Damn Vulnerable Linux (DVL) is not maintained anymore. Are there any other simillar OS´s to download somewhere that ...
83
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 ...
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 ...
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 ...
10
votes
5answers
3k views
Linux command logging?
Recently someone broke into one of our linux servers as a non root user.
An excerpt from .bash_history:
[...]
perl
perl
set +o history
set +o history
set +o history
passwd
sdfsdf
passwd
exit
I ...
5
votes
8answers
2k views
Linux or Windows- the security issue [duplicate]
Possible Duplicate:
Open Source vs Closed Source Systems
Almost anyone who has grown up on Windows must have had the notion (that I had) of Linux being more secure than Windows- one of ...
3
votes
7answers
1k views
Server compromised for 2nd time, cannot locate source of attack
I need some help tracing a vulnerability on my server. For the second time, my server has been compromised with files being replaced with virus-ridden downloads.
According to the filesystem dates, ...
16
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, ...
5
votes
3answers
394 views
Appropriate defense for 404s in my logs - persistent web scans from one region
This seems to be a fairly easy question to figure out, but I wanted to make sure. I've got about a thousand entries on one of my web servers with phpmyadmin in the connection criterion, but as I ...
6
votes
5answers
952 views
How can I remotely wipe the contents of a Linux Laptop if its been stolen?
I am currently investigating using Linux Laptops for my development team. We currently run Windows. The one advantage that keeps coming up for Windows over Linux from a system administration / ...
6
votes
4answers
2k views
How to disable Firewire in OpenBSD/Linux to prevent attacks through Firewire?
Since Firewire lacks security, allowing a plugged-in device to access host memory, it's a good thing to fully disable it. If we're not using the BIOS to disable the Firewire port then how could we do ...
1
vote
4answers
4k views
Netcat IP Spoofing
I am connecting to a server
nc -v 192.168.0.1 1111
But I want to do IP spoofing because the server on 192.168.0.1 only accepting commands from 7.7.7.7. We are two friends, I am 192.168.1.1, and my ...
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 ...
9
votes
1answer
964 views
Effects of DDoS attacks on memory use under Linux
Can someone whose Linux system is under DDoS attacks give me exact data on the effects of the Low Orbit Ion Cannon (LOIC), the High Orbit Ion Cannon (HOIC), Slowloris, PyLoris, Hping etc. on memory ...
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?
...
10
votes
3answers
636 views
VPS security best practice
I've just signed up for a linux VPS to host a website I've been creating and I need some advice on the best approach to secure it.
I've previously been hosting it off a VM in the house, but I want to ...
5
votes
2answers
682 views
Using TPM with DMcrypt?
Is it possible to use TPM for storage of some private key? It's not a full-disk encryption , I want it to be compatible with existing LUKS, just add another key, and store it in the TPM.
7
votes
1answer
3k views
Available Resources for Securing RHEL 6
Some in our infrastructure group want to upgrade to start taking advantage of the new features in RHEL 6. In the past, I have relied on the NSA Guide to secure RHEL 5 and CentOS 5 installations. I ...
6
votes
4answers
1k views
What do I need to configure, to make sure my software uses /dev/urandom?
When setting up a server, what configuration changes do I need to make sure that all of the software uses /dev/urandom instead of /dev/random?
Some servers don't have much entropy in the entropy pool ...
6
votes
7answers
2k views
Physical computer security, how to disable USB ports when the computer is 'locked'?
Lets say my PC & server is in an environment where a theoretical attacker has physical access to the machine while I'm not there. Now the data is encrypted on the hard drive with TrueCrypt. ...
8
votes
4answers
337 views
Best practices for physically securing a notebook
If the user knows that other people will repeatedly have physical access to her notebook - running Linux - while she is absent, and that there is no way around this, what are best practices for ...
8
votes
3answers
805 views
How to manually check for rootkits on a server
Does anyone have a general step by step list on how to try discover rootkits on a Linux or Solaris server?
I'm looking for to to manually find the rootkit, not by automated software.
For example:
...
5
votes
3answers
1k views
Is CentOS a good choice from a security perspective?
How secure is the CentOS Linux distribution? I noticed there were times when there were no up-to-date patches for some version of CentOS (e.g., 5.6). I read this on some mailing list that I can't ...
4
votes
3answers
587 views
Wrapping system call (in reliable and secure way)
It there reliable method of "wrapping" system calls under Linux ?
(Like LD_PRELOAD for wrapping shared library function calls.)
Is there reliable, secure method of "wrapping" system calls (and, maybe ...
3
votes
2answers
2k views
How to secure a dedicated linux server running a LAMP stack for commercial E-commerce use
To be more specific, I would like to get some help, either through a tutorial or through a book, on how to configure an apache server to run securely and minimize the risks for commercial use.
...
7
votes
2answers
334 views
Is a rand from glibc's rand secure for a login key?
Same question as Is a rand from /dev/urandom secure for a login key, but with glibc's rand function instead of /dev/urandom. And what would be a sufficiently secure seed generator?
5
votes
2answers
725 views
Pitfalls of SSD encryption
Encrypting an SSD is a process that is sometimes warned should be done with caution. E.g. http://en.gentoo-wiki.com/wiki/DM-Crypt_with_LUKS mentions how the SSD may keep hidden space used for wear ...
5
votes
2answers
297 views
How can I use nmap to distinguish between a normal linux machine and an android device?
According to this link: here, nmap 5.2 onwards is now supposed to detect android smartphones. I am using nmap 6.01 but it only identifies android devices as running a linux kernel.
5
votes
2answers
804 views
Breaking out of a strict linux sandbox running virtually under windows: do the linux-sandbox access control policies even matter?
I am developing an application which will run untrusted code. I have been designing it for linux, thinking that I can just run it in a virtual machine on windows when the need arises. The linux ...
5
votes
3answers
467 views
Phishing virus found on server
I recently had a call from BELL concerning a virus on our Linux ( Debian ) Server. Apparently Google emailed our client about an Italian Database found on our server that was doing phishing. They ...
4
votes
2answers
554 views
Security Concerns with X11 Forwarding
What are some of the security concerns and reasons either for or against allowing X11 Forwarding. I have generally taken an approach of not allowing it under the blanket guise of security. Recently, ...
4
votes
2answers
579 views
environment variable accessibility in Linux
Perhaps this is a trivial question, but how accessible are environment variables in Linux between different users?
e.g. if Alice executes
export FAVORITE_FOOD=`cat /home/alice/fav_food.txt`
Can ...
3
votes
4answers
875 views
Determining the point of compromise on an infected web server?
Recently a friend of mine has had his web server compromised - all PHP files were injected with malicious code, in particular one that looks to be called "GetMama". If I look this up, it seems that ...
3
votes
3answers
356 views
Pseudo Random Generator is not initialized from the (entropy pool)?
The RHEL5 manuals state that /dev/urandom will use the entropy pool until it's exhausted, and then it will resort to a fall-back pseudo-random algorithm, so that it will never block.
But when ...
2
votes
2answers
531 views
Need advice on linux server being hacked
I'm currently trying to find out how one of our centos servers was compromised. We were experiencing malware on our sites. After searching I finally found the malware injecting into the sites. As it ...
