Securing Linux systems and applications; understanding Linux security features.

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14
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4answers
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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 ...
2
votes
3answers
1k views

discover virus or spyware under Linux

I suspect to be the target of very skilled hackers. 5 or 6 years ago I found spyware on my Linux webserver, it was lkm masked as ppp_deflate module with md5 hash hijacked. I mean with the same md5 ...
2
votes
2answers
1k views

NSA RHEL5 Checklist

The NSA has came up with the "Guide to the Secure Conguration of Red Hat Enterprise Linux 5" (http://www.nsa.gov/ia/_files/os/redhat/NSA_RHEL_5_GUIDE_v4.2.pdf) I have read through this guide and it is ...
2
votes
2answers
774 views

Allow apache to write to users' .ssh dir's

I know the title is just baiting the "your setup is insecure", but allow me to explain. I'm working on an application which aims to allow clients to rsync over SSH to our server. We need a web ...
0
votes
1answer
255 views

Looking for virus under Linux [closed]

if I am looking for a virus/spyware under linux, where should I have to look for to find it ? I suspect to be the target of very skilled hackers. 5 or 6 years ago I found a spyware on my linux box, ...
2
votes
1answer
134 views

Network abnormally slow during night hours

My network recently the last week as become abnormally slow around 11 pm. Very slow buffering youtube videos during all hours. Ive recently purchased the new router about two months ago but not ...
3
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3answers
4k 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?
6
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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. ...
3
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2answers
2k views

What are the best IT auditing guidelines for Red Hat Linux 5.x+, including the critical data protection?

Currently, I am a junior application consultant and we are maintaining huge amounts of redhat machines as servers. I am given the chance and liberty by my boss (unbelieveable!) to go do my own ...
1
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0answers
321 views

Any suggestion for a good readerless smart card (security token) solution? [closed]

I'm developing a small CRM application that will have to store some sensitive data and I would like to (optionally) supply my users with the possibility to use a readerless smart card (aka "security ...
-2
votes
3answers
5k views

Which tool (apart from nmap) can I use to scan a range of IPv6 addresses? [closed]

When I try to use nmap: # nmap -sP -6 FE80::1-234 [...] Failed to resolve given IPv6 hostname/IP: FE80::1-234. Note that you can't use '/mask' or '[1-4,7,100-]' style ranges for IPv6.[...] What ...
2
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2answers
571 views

vulnerable getlogin

I was reading "A taxonomy of Coding Errors" and I have a doubt regarding the point mentioned in C/C++ >> API Abuse >> Often Misused: Authentication(getlogin). I fail to understand the attack vector ...
2
votes
2answers
816 views

up2date tools for security audit linux / centos

I'm setting up a new CentOS 6 server and am looking into some security audit tools to validate my configuration and to point out weak spots in the server. There are a lot of non up2date tools out ...
12
votes
2answers
5k 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 ...
5
votes
2answers
287 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 ...
1
vote
0answers
279 views

Unauthorised Perl Scripts [closed]

One of my servers just had the memory exhausted by a load of Perl scripts, we use plesk and they seem to have appeared under the /var/www/vhosts/domainexample.com/cgi-bin/ directory, I managed to stop ...
7
votes
2answers
358 views

In Linux, when I consider trusting a new software source, what do I need to evaluate?

When I'm using the Linux software PackageKit, I get confused about what specific items of information I will need in order to decide whether to authorize software installation from a new software ...
7
votes
3answers
599 views

How to gain a shell?

I'm doing an exercise (exploit-exercises.com) that requires me to gain access to a shell running as another user. My question is this: I can create application that is guaranteed to be run by the ...
9
votes
6answers
10k views

Good file encryption tools [closed]

Could you please help me find a good file encryption tool? The target OS is Linux, but tools for Windows are welcome, too. FOSS tools are preferred. The tool must be reliable both for the recovery of ...
11
votes
3answers
3k views

Installing Development Tools on Production Server? Security Risk?

I am using an Amazon Linux EC2 instance as a web server. My web app uses ImageMagick. Because the Amazon Linux (CentOS) repository doesn't include an up-to-date version of ImageMagick, I am compiling ...
8
votes
5answers
2k 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 / ...
4
votes
3answers
530 views

Security for home server, wiki

I recently set up my own home server, running Ubuntu linux. The intent I'm having for this is to have a private wiki for my family, so we can have a place to collect information like phone numbers, ...
2
votes
2answers
2k views

How do I figure out how malware infected my server, and the subsequent sites on the server?

I recently was in charge of fixing our server at work, and cleaning the sites on it. We were infected with some malware that injected some code into some of our clients websites. Apparently, there was ...
3
votes
3answers
2k views

Writing a sample virus (not harmful)

I don't know if such a question is allowed on this site, sorry if it's not For educational purposes I am asked to write a small virus running on Linux, which should just be able to inject itself into ...
10
votes
1answer
2k 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 ...
6
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3answers
5k 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)?
0
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5answers
948 views

What voip client support manual encryption?

In pidgin there is a plugin that we can use to encrypt our messages in chat windows .. Is there anything simular for voip (pc to pc) ? any client that support manual encryption for voice data?(linux)
5
votes
1answer
985 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 ...
7
votes
2answers
7k views

Benefits to Arch Linux over Kali Linux

What are the relative benefits of BlackArch or other Arch-based distro over Kali? Are the tools broadly the same, or does one have better functionality in a particular area? Are there any other ...
9
votes
7answers
1k views

How are open-sourced operating systems and software kept secure?

I have been wondering about his for awhile. I have Linux running on a PC at home. I had a jailbroken iPhone. They both have attributes that make them very attractive, and they are also FREE! But I ...
1
vote
1answer
2k views

How can log poisoning be successful with a Local File Inclusion attack?

I just read a paper about Local File Inclusion on exploit-db.com, it can be found here. One technique with LFI is log poisoning as you may know already. You do an HTTP GET request that contains PHP ...
3
votes
2answers
1k 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 ...
4
votes
1answer
6k 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 ...
14
votes
3answers
2k 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
3answers
1k views

Making passwd/shadow files more secure

The passwd/shadow files in a unix-like OS contain sensitive info such as a user's password. In addition those files aren't necessarily secured: with a live CD we can access those files on the hard ...
3
votes
2answers
871 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 ...
6
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2answers
6k 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
1k 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 ...
12
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8answers
8k 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 ...
9
votes
1answer
1k views

Securing restricted shell environments

I've read a few things to indicate that restricted shells can be broken out of if not implemented properly (even wikipedia, for instance). I'm looking for some guidance on what causes security holes ...
11
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3answers
2k views

Which Linux kernel vulnerabilities allow installing a kernel-level rootkit?

My question is related to vulnerabilities that allow installing a Linux kernel-level rootkit (for example, to modify the execution flow inside the kernel; for return-oriented attacks; or to modify ...
14
votes
2answers
16k views

Sudo password when authenticating via passwordless SSH

I've got a few boxes all networked together on Amazon EC2, each of which are in automated communication with each other via SSH (rsync, etc). As such, I've created SSH keys on each of these machines ...
7
votes
7answers
3k 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, ...
5
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 ...
6
votes
1answer
3k views

loop-aes or dm-crypt for linux hard encryption?

loop-aes and dm-crypt are both used by partman-crypto for linux hard encryption, but dm-crypt needs no patch to kernel and is more supported. dm-crypt keeps it's key on first hard block, is it a ...
1
vote
1answer
1k views

Can you describe a real-life scenario of exploiting sticky bits?

Sticky bit are mentioned in every UNIX security book, but I couldn't find anyone that describes the exploitation of Sticky Bit set on a file. Can you?
3
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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 ...
5
votes
1answer
2k views

ARP-poisoning on wireless network - no packets

I've started working with ettercap and ARP-poisoning; however, I've sumbled upon some problems. I've executed the following command: ettercap -i wlan0 -w log -T -M arp:remote /192.168.1.254/ ...
15
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7answers
4k views

Convenient cross-platform help on checking secure hashes like SHA-256

It is often helpful to be able to obtain a good cryptographic checksum of a file, e.g. the SHA-256 hash. This can be used to verify file integrity, so long as you have a reliable source for the hash. ...
8
votes
4answers
10k 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 ...