Securing Linux systems and applications; understanding Linux security features.

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4answers
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Recommendations for Changing the Default Shell For Service Accounts

It seems as if most Linux systems use either /sbin/nologin or /bin/false as the default shell for service accounts. Many hardening guides, such as CIS benchmarks, recommend changing the default shell ...
5
votes
3answers
597 views

Increase security without using “dynamic” kernel modules?

I recently read that NOT using loadable kernel modules could increase security. In my interpretation this consist about recomplying the kernel with only built-in kernel modules. (how to disable ...
1
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3answers
292 views

Is there a security problem accessing my laptop via WIFI?

I'm developing a web application for mobile devices on my local server in my laptop. My laptop is connected to company network via LAN. And, my project manager, wants to check the web application ...
5
votes
3answers
382 views

What are the security considerations for setting up a basic security testing environment?

I only have 2 spare machines and both are very old, but I really want to set up an environment so that I can start practicing security. One of these machines has a Pentium 4 processor and 512 MB RAM; ...
6
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3answers
470 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 ...
3
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2answers
225 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 ...
9
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2answers
3k views

For LUKS: The most preferable and safest cipher?

I'm about to encrypt two of my hard drives using LUKS, since I can't really do it myself I use the guide on the Arch Linux wiki (which can be found here). In an example in the guide the cipher ...
13
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2answers
957 views

Can Windows malware harm a Linux computer when it's executed with Wine?

I am an (Ubuntu) Linux user. Sometimes, I have to use Wine for running Windows executables. I would like to know if Windows malware (virus, trojan, worm,...), i.e. malware that was not intended to ...
4
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3answers
439 views

How do I protect myself against the attacks in this php script?

Due to a vulnerability in how PHP was installed (Shared VPS with PHP installed as an Apache module instead of CGI) and hence how OSCommerce was configured (with security of 777 on certain ...
8
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2answers
487 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?
9
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2answers
1k views

Securing my web-server / website [closed]

Does anyone know of a comprehensive security guide about important basics / fundamentals which should be done to secure a web-server / website? A web link would do.
3
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1answer
458 views

Two questions about learning Linux exploit development fundamentals

getting ready to delve into the technical world of vulnerability assessment, and I have two questions about where to find certain information. First, I plan on reading "Understanding the Linux ...
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3answers
984 views

Why are people saying that X-windows is not secure?

Why are people saying that X is not secure? With X I mean: https://secure.wikimedia.org/wikipedia/en/wiki/X_Window_System p.s.: The OpenBSD team succeeded with priviledge separation in 2003, WHY ...
21
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3answers
14k 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, ...
12
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5answers
6k 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
4answers
17k views

Tips for a secure iptables config to defend from attacks. (client side!)

Own examples: ############### # KERNEL PARAMETER CONFIGURATION # PREVENT YOU SYSTEM FROM ANSWERING ICMP ECHO REQUESTS echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all # DROP ICMP ECHO-REQUEST ...
4
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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 ...
6
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1answer
2k views

Using TPM for full disc encryption?

E.g.: Can I make a better full disc encryption with e.g.: LUKS using the TPM? How?
5
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4answers
167 views

software to keep a list of IP that try to access ssh over a set of rules and feasibility

i'm interested in software or set of scripts to keep a lists of filtered IP that attempt to brute-force ssh, and to label an IP as brute-forcing i would add some checks like: one attempt to log as ...
8
votes
3answers
1k 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: ...
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: ...
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vote
2answers
2k views

IPTables default security rules for a gateway/router?

On a router such as dd-wrt or tomato, what would be some default iptables rules? I am asking for rules on a router/gateway - For example; blocking SYN flood attacks, or XMAS attacks. The basic ...
9
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2answers
3k views

Recommend Keylogger for Ubuntu?

I purchased a new laptop recently, and I'm working on hardening it. Specifically, I'm interested in increasing my chances of recovering the machine in the event that it's ever stolen. The system ...
26
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6answers
3k 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 ...
8
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4answers
3k 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 ...
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2answers
185 views

How to store my contacts encrypted?

I use KeePass for storing my passwords. What should I use if I want to store my several hundred contacts (name, phone number, email, etc) encrypted?
5
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3answers
2k views

How to detect Meterpreter and similar malware?

Is it possible to find Meterpreter or similar malware which doesn't modify the hard disk but is only stored in RAM? Most common anti-rootkit software like rkhunter and chkrootkit don't find it.
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3answers
112 views

Could an Encrypted VG/Image compromised?

I mean if I encrypt my ""full system"" so that everything (besides the /boot) is in an encrypted VolumeGroup (Linux). So I store my /boot on a flash drive, thats always next to me. Q: can the ...
5
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1answer
785 views

Does Fedora 15 still use suid bits?

I heard that Fedora 15 will not use suid bits. Is that true? Is the suid bit a security design bug?
61
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3answers
7k 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 ...
14
votes
1answer
841 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 ...
5
votes
3answers
629 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 ...
8
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3answers
3k 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 ...
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7answers
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Secure memcpy for pure C

Buffer overflows are nothing new. And yet they still appear often, especially in native (i.e. not managed) code... Part of the root cause, is usage of "unsafe" functions, including C++ staples ...
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4answers
3k views

How To - Learn basic hacking skills? [closed]

I'm interested in learning some basic hacking; and I've read online that Linux is a good place to start. Although, I've been a Windows user for as long as I can remember. So I was hoping I could get a ...
5
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1answer
660 views

Linux wireless hacking book

I am looking for recommendations on a good wireless hacking book. I would like something more focused towards the defensive, but a healthy knowledge of both would be great. I would also need it to go ...
3
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1answer
654 views

Firewall rules to block unwanted protocols on given ports

Does somebody has an idea, that what kind of iptables/pf rule must i use to achieve this?: i only want to allow these connections [on the output chain]: on port 53 output only allow udp - dns on ...
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
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3answers
1k views

How to use VNC with SSH tunnel - “is this howto secure”?

PC-A: the local machine, from where i want to see the remote machine [Fedora] PC-B: the remote machine, where the vnc server will be [Ubuntu] install a vnc client [from where you want to connect] on ...
4
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2answers
413 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 ...
7
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2answers
2k views

Best way for a hacker to hide a file on Linux?

Suppose a hacker obtains a shell on my Linux host and wants to hide a file. What's the best way for him to do this? You may assume unprivileged or root access. My thoughts are Use a .file ...
3
votes
1answer
1k views

Does the Ophcrack LiveCD require hash collection via programs like pwdump?

When I used the Ophcrack LiveCD recently, the program automatically ran without me manually loading any hashes. Question is: If Ophcrack does not automatically find hashes, how can I go about ...
10
votes
1answer
638 views

Relative importance of CHROOT for web servers

I have read extremely mixed opinions on the process of chrooting for a web server (non-shared environment). Some people swear by it, yet others say that it isn't as secure as everyone says. Given ...
10
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3answers
438 views

Given SSH access, what should I do to protect a server and monitor (dangerous) user actions?

Context: Small business, mostly a software house for web applications but also some desktop software. Many external collaborators, so a variety of outside users with access to the servers. Single ...
16
votes
8answers
4k 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 ...
61
votes
9answers
9k 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 ...
4
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2answers
230 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 ...
6
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2answers
372 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 ...
15
votes
3answers
949 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) ...
9
votes
1answer
260 views

What shell binary should I use for the root account on a Linux system?

Is there a security advantage to using a different shell for the root account, either a hardened shell program, or simply a shell binary stored in a non-standard location?