Securing Linux systems and applications; understanding Linux security features.

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7
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2answers
357 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
591 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
522 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
940 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
953 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
1answer
6k 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 ...
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
850 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 ...
5
votes
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
votes
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
votes
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
15k 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
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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
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 ...
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
votes
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
9k 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
1k 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 ...
12
votes
6answers
1k views

Securely building a local pentest lab in a VM

I'd like to set up OWASP WebGoat or a similar vulnerable web app in a VM (probably VirtualBox on Linux). For convenience's sake, I'd like to get it running on one of the primary machines I use (say, a ...
7
votes
5answers
2k views

Fastest way to “lockdown” CentOS and have network intrusion detection, firewall, etc up and running?

Are there any proven concepts or "installers" to get up and running based on the best practices securing and locking down a CentOS installation? I'm hoping for an automated tool that would scan the ...
5
votes
2answers
3k views

Preventing Attacks Scanning for PHPMyAdmin etc

I have a Linux web server running Rails and each time I check the Nginx logs I find attempts to access PHPMyAdmin, database and admin directories such as this: 190.196.161.110 - - ...
1
vote
1answer
682 views

Should Windows 2008 R2 be used as an externally facing DNS name server?

When compared to more traditional DNS name servers, what are the benefits / drawbacks of using a Windows 2008 R2 as a public ns record for a company. What limitations, or security issues would I ...
33
votes
6answers
7k 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 ...
2
votes
0answers
696 views

Adding an alternative password change scheme to passwd using PAM modules [closed]

I am trying to set up a PAM module that lets one add a conditional password change scheme. The intended behavior is like this: passwd do you want to change authentication token for ...
28
votes
4answers
21k 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 ...
8
votes
4answers
461 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 ...
4
votes
2answers
634 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 ...
13
votes
1answer
881 views

Are there Linux rootkits circulating that directly modify the kernel (without modules)?

It has been said, over and over, that disabling dynamic kernel module loading on Linux increases security. I understand why people give this advice, but I've always assumed that a bad guy could ...
3
votes
2answers
2k views

/dev/random security holes

I'm doing some reading into the security issues surrounding /dev/random but it's proving to be hard to find good sources of information. Can anybody help? I've asked Google and got a bunch of articles ...
2
votes
1answer
547 views

NFS and encrypted File systems

Can a NFS mounted file system be used for encrypted /home, and can the encrypted Home Directories be mounted/decrypted for the user when they login?
9
votes
2answers
523 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 ...
17
votes
6answers
4k views

How can I protect my computer from my potentially malicious colleagues?

So, I work in this small company (10 people) where we do stuff in programming, for various platforms. I started recently working there (2 months) right after I graduated. My work is not exactly ...
15
votes
2answers
768 views

Network policies under AppArmor/SELinux

I am attempting to sandbox some untrusted processes using Linux's MAC frameworks -- either SELinux or AppArmor. I see that both SELinux and AppArmor allow the selected granting of socket level access ...