Securing Linux systems and applications; understanding Linux security features.

learn more… | top users | synonyms

4
votes
2answers
2k 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 ...
4
votes
3answers
441 views

Live Linux which does not mount any hard drive in the computer

I am searching for a Linux System which runs from a CD and does not mount any hard drive of the computer. I want to prevent any possiblity to write something on the hard drive of the computer and on ...
4
votes
1answer
926 views

Server monitoring for security

We do a lot of web hosting management and have started to get into selling server management packages. However, we want to start monitoring servers for security related threats. Our clients may use ...
4
votes
2answers
268 views

Securing data on laptop's hdd

I was wondering which is the best way to secure/encrypt data in the hard disk on a laptop that runs Ubuntu Oneiric? Setting LVM encryption? I am mostly concerned about having my laptop lost or what ...
4
votes
2answers
529 views

Protecting data on a laptop with linux

I'd like to keep some private data (photos, notes, ...) and my browsing data hidden. The rest is not so important. Most of the time I just put the laptop to sleep and don't shut it down often, making ...
4
votes
2answers
1k views

Impact of Mathew Garrett's Secure GRUB Bootloader on UEFI Secure Boot

My eyebrows rose with Matthew Garrett announcing his Secure GRUB Bootloader less than three hours after no longer being a Red Hat employee. This work and its impact on the trust chain design of the ...
4
votes
2answers
543 views

Detect changes in /boot when using full disk encryption

When running a fully encrypted linux system using dm-crypt, the /boot partition has to be unencrypted to boot, as far as I know. I've setup a server that can be unlocked remotely by connecting to a ...
4
votes
1answer
4k views

what does it mean to be setuid root?

I am reading Tanenbaum's Modern Operating Systems 3e. He says "Suppose that the program being attacked [with malicious code] is SETUID root in UNIX (or has Administrator power in Windows). The ...
4
votes
1answer
5k views

Fail2Ban does not ban failed root login attempt

I have a small server which only open ports are ssh, http and https. I have fail2ban installed and set up so that after 3 failed attempts someone gets blocked for 10 minutes (thats the dafault I ...
4
votes
2answers
142 views

You've just acquired a newly created CentOS server, what should you do to secure it?

I've just acquired a new CentOS server, which will be hosting a Ruby on rails application, it is public facing. What should I do to secure this server?
4
votes
2answers
294 views

Vulnerability testing without the use of exploits?

I was doing some testing on a server to see if it was vulnerable to a 0-day local exploit (the exploit was for gaining root privileges using a bug in the Linux kernel). There was no real information ...
4
votes
1answer
316 views

Exploited by newbie3viLc063s

My debian server got exploited by some scriptiekiddie who used Newbie3viLc063 http://pastebin.com/jma8JRG1 . Scriptkiddie uploaded logo_php.png to my server (My permissions sucked :s) and he did run ...
4
votes
1answer
1k views

What tools can be use for Security Auditing for Redhat

Are there any good tools that can be used for Security auditing of Redhat Linux. That can audit all the critical areas of System and provide the detailed output of all the audited sections.
4
votes
2answers
1k views

Can you have 2 promiscuous (sniffing) ports on a single machine?

I'm wondering if you can actually have 2 (or more) promiscuous (sniffing) ports on a single machine, to monitor multiple network segments? And can you monitor them all with snort?
4
votes
2answers
550 views

Securing Docker and LXC

The concept put forward by Docker and LXC seems to be, from a security perspective, a move in the right direction. Afraid of a MySQL zero-day? Run it in a Docker container and it won't be able to ...
4
votes
2answers
181 views

Erasing encryption (LUKS) keys before suspend-to-RAM?

I recently had been wondering if there is a way to erase my LUKS keys from RAM before I suspend my device (usually a laptop) to S3 mode. I am interested in a solution that would work for my / ...
4
votes
1answer
240 views

Are we under hacker control?

We have a Web Server that mount Centos. Onto that WS there is an Apache (version 2.2.3) and some sites. You can log on only if you have a certificate (for root user) or via ftp (a restricted ...
4
votes
3answers
3k views

How to scan USB drive with clamav on Linux

Is there a way to scan the entire drive including auto-run and all partitions, including the master boot record (MBR)?
4
votes
1answer
2k views

Benefits to BlackArch over Kali

Besides BlackArch having a cooler name and the whole Ubuntu vs. Arch Linux thing, what are the relative benefits of BlackArch over Kali? Are the tools broadly the same, or does one have better ...
4
votes
2answers
134 views

Can my /boot be compromised if I Suspend my notebook?

So if I use e.g.: LUKS, and I always suspend my notebook, then are there any methods to modify the unencrypted /boot? It contains the kernel! Or if someone tries (evil maid) to modify the /boot then ...
4
votes
2answers
238 views

What does a MCSE need to learn to be proficient regarding *nix security?

I have a top notch Windows MCSE/MCSD (developer) who wants to broaden his skills with Linux security... but needs to update his skills from the Ultrix / Yellowpages days of 40 years ago. What ...
4
votes
2answers
507 views

Executing arbitrary commands through iptables-restore input

During a pentest I found a way to add arbitrary iptables firewall rules to a server. These rules get applied by way of the iptables-restore command, and I've been wondering whether there is any way to ...
4
votes
1answer
478 views

Can auditd track events that occured over NFS

I have multiple servers mounting a NFS shared called /opt/WHATEVER from Server X. Server X has auditd enables with rule: sudo /sbin/auditctl -w /opt/WHATEVER -p rwxa When events occur on Server X ...
4
votes
1answer
739 views

Why ESTABLISHED,RELATED for INPUT only?

In many places and tutorials I see people add this line to their iptables: -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT And they do it only and only for "INPUT". What about OUTPUT and ...
4
votes
1answer
115 views

Does Linux kernel use DEP for kernel memory?

Does the Linux kernel use DEP internally for its kernel memory? In other words, does the Linux kernel take care to ensure that, when the kernel is executing (in kernel mode), every executable ...
4
votes
3answers
230 views

What would the cryptographic impact be of knowing the output of /dev/urandom?

Another noob question, I know, but something I'm unsure about. If I somehow magically knew the output of /dev/urandom at any given time, how much would that weaken a given encryption system? Or, ...
4
votes
2answers
415 views

How to improve VPS security?

I’m using Linux based VPS hosting, and a firewall and mod_sec help to keep most hackers out. However, over the last couple of weeks I noticed several entries in mod_sec showing that an unknown domain ...
4
votes
1answer
77 views

Is a Linux environment PCI compliant if the swap file is not encrypted and PANs are loaded into RAM?

Is a Linux environment PCI compliant if the swap partition/file is not encrypted and PANs are loaded into RAM by an application?
4
votes
1answer
596 views

Are Linux vendor-supplied security updates enough for PCI Compliance?

I have several systems that require PCI compliance, all of them are running CentOS 6.4 with all security updates applied daily. However, PCI compliance scanning will often reject detected versions of ...
4
votes
2answers
651 views

What Ubuntu packages are still affected by gnutls bug CVE-2014-0092?

Right now the internet is abuzz with news about a severe breach in GnuTLS. An update to the relevant GnuTLS packages has already been released. But I am worried whether some packages might have had ...
4
votes
0answers
124 views

Bootstrapping an EC2 Spot Instance

I'm considering using EC2 Spot Instances in an automated fashion (ie create a script that will request EC2 Spot Instances that will run unattended). For this specific use case, I'm happy to lock down ...
4
votes
3answers
951 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
4answers
569 views

does switching to linux remove existing computer virus

if you change from a malware/spyware infected windows setup to a linux setup will infections migrate to linux if they were on the computer? (when you are hacked/infected is it the op system that is ...
3
votes
3answers
2k views

Privilege Escalation Ubuntu

I am trying to learn how an attacker can escalate privileges in Ubuntu 10.04. I have heard that this can be done but no one has ever said how to do it. The best defense is knowing how it is done and ...
3
votes
3answers
629 views

Online security check via command line

My scenario is that I have a VPS with Apache (mostly for development of my own projects) accessed via SSH; and I time to time I would like to do a quick check just to be sure that there's no potential ...
3
votes
3answers
264 views

Best security practices for software development and release?

I am trying to figure out a way to limit access and also to establish processes to avoid any and all of my team members to compromise our entire production system. We have a team of 10 developers, 1 ...
3
votes
3answers
2k views

Besides OpenVas and Nessus, what are my other options for vulnerability detection?

I know of Nessus (which is $1300 for a pro feed) and OpenVAS (which I don't like). I use Linux so do I have any other options for vulnerability detection?
3
votes
5answers
1k views

Secure mount options + partitioning on Ubuntu

What is the best solution for mount options/partitioning when having e.g.: an Ubuntu minimal install (11.04) for Desktop use? e.g.: put /tmp on different partition to give it mount options like: ...
3
votes
1answer
772 views

How to remove ssh rootkits? [duplicate]

I checked my linux server with rkhunter, I got following warning messages, ... [00:35:35] Found file '/usr/include/gpm2.h'. Possible rootkit: Trojaned SSH daemon [00:35:35] ...
3
votes
3answers
264 views

Why should every file have a user and a group?

I've been reading in most hardening guides for linux, that you should check for files and directories without valid user or valid group. What I can't find, is how this could be used for an attack, or ...
3
votes
3answers
2k views

Disable Perl for some/most Linux users?

One of my server's web accounts got hacked a couple of times. Each time someone downloaded a Perl script via some phpBB forum and used the Perl script to do whatever they wanted to do (mostly connect ...
3
votes
2answers
886 views

Is GPG suitable as part of a password manager and generator?

I assume that GPG is very strong to crack, guess, etc. Since I have confidence in GPG, would it be appropriate to use my GPG key as the master key for a password manager or generator?
3
votes
3answers
120 views

Can the root of a system access to unencrypted data when using a double tunnel?

I connect to a DMZ gateway system (B) which is not secured. From this machine (B) I can connect to the final destination (C). A-->B-->C I created a ssh tunnel from A to B and forwarding the port 22 ...
3
votes
5answers
332 views

Blocking network access to host(s) at the kernel level in Linux?

Getting it out of the way: Not iptables! What I'd like to do is block network access to certain IPs, subnets, and/or hostnames at the Linux kernel level, such that no user, including root, could ...
3
votes
2answers
934 views

Securing a Ubuntu system on Amazon Web Services

I'm in the process of setting up a Ubuntu server on Amazon Web Services / EC2, which will need to host the following: A relatively simple Java-based website (using the Noir framework) A Java-based ...
3
votes
2answers
3k views

Decrypt from cipher text encrypted using RSA

I am sniffing a client side application traffic and I found some encrypted data. I am not able to decrypt it. Information which I have is Public Key: ...
3
votes
2answers
246 views

Which access rights should be chosen for doku wiki?

I'm currently making my first experiences with a CMS called "DokuWiki" (Link). This CMS needs only PHP and writes the information to files (seems to be /dokuwiki/data/pages). At the moment I gave the ...
3
votes
3answers
787 views

Using /usr/bin/passwd as login shell

I have a requirement to set up a SSH tunnel between two hosts. SSH server runs on a Linux host, and the SSH client (PuTTY) runs on a Windows host. I have set up a separate user account (say 'tunnel') ...
3
votes
4answers
2k 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
2answers
714 views

Difference between vulnerabilities on windows/linux/mac for same program

If someone finds a vulnerability like buffer overflow in a program such as Google Chrome or Mozilla Firefox running on a linux machine, are there any chances that this vulnerability will persist on ...