Securing Linux systems and applications; understanding Linux security features.

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14
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4answers
3k 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 ...
0
votes
2answers
329 views

Clarifying MITM attacks and Digital Certificate requirement

We are running a Portal application for our client with Payment Gateway integrated. Payment gateway uses SSL as it is suppose to be . The concern for me is that our Portal application does not use ...
0
votes
1answer
158 views

benefits of xinetd for a web server

What are the pros and cons of using xinetd for a web server running on a VPS. Assume the following measures have already been taken to secure the system: system hardening, latest updates, minimal ...
1
vote
2answers
81 views

How can we know which debian package correct which CVE

We can found on the debian's website CPE/Aliases List, CVE List related to packages. But I can't figure out where can we know which patch of packages correct which vulnerabilities ? For instance : ...
4
votes
2answers
204 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?
-2
votes
1answer
151 views

Proccess to exploit an OS vulnerability [closed]

What are the steps to use an exploit on an OS vulnerability? I tried the popular ms08-067 on an XP machine, following a guide found on the internet, discovering Metasploit etc., but I can't figure ...
16
votes
7answers
2k views

Defence Against Keyboard Keylogger

I am wondering whether there is a way to defend against USB Keyboard Keylogger (obviously other than physically checking the keyboard every time after leaving my computer unattended). These days, ...
7
votes
3answers
3k views

How to sandbox Iceweasel (Firefox) on Debian? [closed]

Are there any tools for sandboxing Iceweasel (Firefox) on Debian systems? I'm mostly interested in tools distributed by Debian. (An equally trustworthy source would be second best.) (I suppose that ...
2
votes
2answers
203 views

What's there to harden for a home Unix-box behind Comcast cable modem?

I'm learning that much of the security advice I come across under the "hardening" heading simply does not apply to a single-user home desktop box sitting in a private wireless IPv4 LAN behind a ...
2
votes
2answers
423 views

I've found security vulnerability in current linux distribution. What next?

I've installed ubuntu server 12.04 on VM two weeks ago. I've created regular snapshots. XXX time ago I've noticed unusual activity and I've found that a backdoor was installed into my server. One of ...
52
votes
7answers
5k views

Can “cat-ing” a file be a potential security risk?

I often use cat on the console to view the contents of files, and every now and then I accidentally cat a binary file which basically produces gibberish and system beeps. However today I've ...
3
votes
3answers
566 views

Protect partition from formatting

How can i protect my Linux and Windows partitions from being wiped,from a windows installation CD,with password?
2
votes
2answers
69 views

Is there a website or other resource that lists operating systems/platforms and the included root certificates?

I need to choose a certification authority (CA), to get a certificate, but I noticed that there are several of these only present in some operating systems/platforms like windows. I need to choose one ...
1
vote
2answers
145 views

Open Source OS - code you see vs code you get

In this question I will use the example of Linux OS, but I am also interested in general situation. Linux OS distributions are famous for being open source and thus rather secure. But how can you be ...
2
votes
3answers
188 views

How to setup a dedicated home machine (Linux) for secure transactions?

I would like to set up a computer at home (preferably running Debian, or some other flavor of Linux) to be used only for secure financial transactions. The idea is that, by strictly limiting what is ...
3
votes
2answers
180 views

How do shared hosts protect different sites?

I host all my websites from a single VPN, and am about to sell some limited space of my Linode to a friend to host their new blog. It'll simply be another entry in Apache, and then a dedicated folder ...
19
votes
4answers
5k views

How secure is NOPASSWD in passwordless sudo mode?

On all our boxes we have ssh access via keys. All keys are password protected. At this moment the sudo mode is not passwordless. Because the number of VMs are growing in our setup, we investigate the ...
1
vote
5answers
2k views

Encrypt-function inside PHP code that you have to publish

If you write a PHP application, where you have to deliver the compiled code to the customer, how could you include a functionality to send encrypted data from that application to others, and include ...
1
vote
3answers
765 views

What is the most secure way to set up web server user permissions? [closed]

The default Debian way of setting up a common web server (Nginx) is to run the main process as root and unprivileged workers as www-data. In order to allow for the worker processes to read/execute web ...
3
votes
4answers
776 views

Find out what Linux software is trying to phone home

I have seen some suspicious outbound communications blocked on my VPS, which hosts a small experimental Web site, and want to find out which application is making the attempt. The server is running ...
0
votes
2answers
103 views

Encryption in Linux: covenience and security [closed]

I was using TrueCrypt until recently, until one of two options has happened: either it was discontinued or its web-site truecrypt.org was hacked. Any option implies that I don't trust it anymore. So ...
0
votes
1answer
233 views

How to secure an embedded linux image

I'm building an image with openwrt sdk and i want to secure my image (by encrypting filesystem for example).. How can i do that to prevent anyone from seeing my sscripts or programs running ?
15
votes
5answers
4k views

Hackable linux distributions

A few years ago we had that awesome Linux distribution called Damn Vulnerable Linux. But unfortunately it looks like the project is dead. So my question is are there other Linux distributions which ...
6
votes
2answers
413 views

How often is ASLR randomness refreshed, in Linux?

Most Linux distributions now use ASLR for many programs, to randomize the layout of memory. How often is the randomness used for this changed? If I re-run the same program multiple times, will it ...
0
votes
1answer
578 views

VPN tunnel in VPN tunnel

I'm wondering if there is an easy way to establish VPN tunnels through other VPN tunnels to get onion routing like properties (sender anonymity). Since VPN builds a tunnel, it should be easy to set up ...
1
vote
4answers
236 views

How to detect credit cards harvested from memory?

Had a chat recently with PCI compliance specialist and got to realize there is a way to steal raw data from Apache / Nginx memory e.g. credit cards. It's called "harvesting" and becomes pretty common. ...
6
votes
7answers
7k 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
3k views

Security of the KWallet password encrypting application?

According to http://gaganpreet.in/blog/2013/07/24/kwallet-security-analysis/ , the KWallet password management system is quite weak, it uses key splitting, Blowfish 56, and no salt. The key ...
0
votes
3answers
608 views

How to secure ubuntu desktop after a hack? [closed]

I have two ubuntu laptops that were recently compromised. I understand that it's probably a fruitless endeavor to try to find the hacker. I want to know how to secure my ubuntu desktop so that the ...
0
votes
3answers
394 views

How to set iptables to drop packets that I'm not listening on?

I've got a Kali Linux box I use for pen testing. I would like to configure my machine to DROP incoming packets, but only when I'm not listening on them. e.g. if I run a netcat listener on port 80, I ...
3
votes
2answers
127 views

security via chsh

I am developing a program that I want people to be able to connect to and use via ssh. I've decided a simple way of doing this would be to create an account for them on my linux server, and change ...
2
votes
2answers
136 views

Securing data on a server

I have a server which has 'loose' physical security (somewhat easy for the entire server to get stolen). For the sake of the question, let's assume that anyone can access the server physically, what ...
2
votes
3answers
576 views

Encrypting Backups on Linux

I'm working on an automated backup solution to protect my files on my Linux servers. However, I'm not sure about how to securely encrypt the resulting archives. I am using 64bit linux, and I am ...
1
vote
0answers
214 views

How should I configure my Tor-dedicated firewall for optimum security?

I'm setting up a Tor-based isolating proxy using the 'Anonymizing Middlebox' iptables rules specified here: https://trac.torproject.org/projects/tor/wiki/doc/TransparentProxy i.e. iptables -t nat ...
17
votes
7answers
6k views

Any comprehensive solutions for binary code protection and anti-reverse-engineering? [closed]

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 ...
1
vote
3answers
693 views

Best practice for accessing management port of firewall

I'm in the process of setting up a bunch of servers at the other end of the world (well, 8 hours travel time) in a co-location place. The servers and firewall all have a remote management port (KVM, ...
2
votes
1answer
127 views

Analyzing a suspicious email

Today I received a very suspicious email on my gmail account. When I analyzed the content of the message, this is what essentially made up the message. <center> <a alt="" ...
0
votes
2answers
292 views

Ubuntu LVM LUKS Encryption

I've been reading about Ubuntu LVM Encryption, and I understand that it supports the use of Linux Unified Key Setup (LUKS) during installation, which is a block level encryption that encrypts the ...
1
vote
1answer
96 views

How to validate the confirmation link received when publishing a new PGP key?

I find PGP to be quite a complex subject. I have gotten to a point where I need to give a client a public key for encryption. I have successfully done my homework, generating a public key from my ...
2
votes
1answer
163 views

Security Features enabled in Linux Debian and Ubuntu

i am actually doing some tutorials about ROP on Linux. So i tried to follow the tutorial and compiled some of the example codes to try ROP in a small scope. But actually when i am trying to exploit ...
1
vote
3answers
117 views

Is it safe to share my hostname

I am using GNU/Linux. Sometimes, I copy/paste code from the terminal (like user@hostname ..) to put it in a forum thread or a blog ..etc And I was always wondering that it is better to hide it . Is ...
5
votes
1answer
394 views

How to detect malicious code sending information to attacker's server in linux

Suppose you have some malicious code on your linux laptop, for example a rootkit or trojan or something like that. Now restrict your attention to the case that the malicious code does transfer some ...
9
votes
2answers
582 views

Running proprietary software on Linux safely

As a summer project, I'm looking to prevent any piece of proprietary software like many games I run from have access to my personal files. After looking a lot at sandboxing, I've decided that anything ...
-1
votes
2answers
406 views

Secure Way of Encrypting Your Bash Shell Script [duplicate]

How can I encrypt my bash shell script on Linux server The shell script contain credentials of other servers for remote access. The problem is I do not want others with same level of access to view ...
-4
votes
1answer
192 views

Most secure SSH server [closed]

Which SSH server (compatible with Debian Wheezy) has the fewest (if any) exploitable security bugs?
3
votes
4answers
231 views

One computer with multiple OSs in different drives

I use my personal computer for both programming work and gaming at my free time(and sometimes penetration testing) all these in different operating systems each. The problem is that I dont really ...
1
vote
1answer
342 views

Linux kernel 3+ system call table modification detection [closed]

Is there any available tool which can check kernel 3+ system call table for modifications? Also I want to know, is there any automated general tool to check Linux for unknown rootkits? Not like ...
-2
votes
1answer
844 views

Linux tools to choose suitable Cisco ASA 5500

I have a linux webhosting server which affects a high DDOS. I want to use Cisco ASA 5500 Series Adaptive Security Appliances to protect the linux server from this DDOS. I know there are many factors ...
1
vote
1answer
1k views

What to do with .hash files when cracking WPA2

So, I'd say I'm one level above n00b. I've gotten to the point where I have accomplished a WPA Handshake (and saved the output as xxx-01.cap). I have also downloaded these hash tables (if that is the ...
13
votes
2answers
817 views

Getting exploit reliability when using the off by one framepointer overwrite on linux

We have a program that is vulnerable to a one byte frame pointer overwrite. The stack is marked executable, the Linux machine has aslr disabled, stack cookies are disabled, and it's a little endian ...