Securing Linux systems and applications; understanding Linux security features.
2
votes
2answers
389 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 ...
1
vote
0answers
219 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
3answers
379 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 ...
7
votes
2answers
258 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 ...
0
votes
0answers
225 views
Using more multiple VPN client's to connect to the same CISCO ASA VPN client connection [closed]
I am currently using CISCO VPN client in a Read Hat Linux machine to connect to a CISCO ASA.
I am planing to connect another LINUX maching to the same ASA using the CISCO VPN client.
Does any ...
3
votes
5answers
987 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: ...
2
votes
2answers
395 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 ...
6
votes
4answers
2k 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 ...
8
votes
3answers
1k 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 ...
13
votes
1answer
507 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 ...
6
votes
5answers
960 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 / ...
10
votes
3answers
638 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 ...
9
votes
1answer
969 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 ...
3
votes
2answers
242 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, ...
1
vote
2answers
719 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
0answers
82 views
Apparmor policies w/ subprocess failing [closed]
Can anyone possibly explain why Apparmor is not picking up profiles for sub-processes of a process? Right now we use God to launch an unstoppable Ruby process (in this case it's /usr/local/bin/remote) ...
3
votes
1answer
326 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
3answers
378 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 ...
6
votes
7answers
704 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
577 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 ...
5
votes
3answers
495 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 ...
6
votes
1answer
1k 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 ...
4
votes
3answers
815 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 ...
3
votes
2answers
2k 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.
...
6
votes
1answer
792 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 ...
5
votes
2answers
808 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 ...
4
votes
3answers
592 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 ...
6
votes
2answers
4k 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 ...
8
votes
2answers
1k 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 ...
2
votes
3answers
990 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 ...
22
votes
6answers
2k 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 ...
19
votes
6answers
2k 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 ...
0
votes
0answers
431 views
Ubuntu home folder encryption, compared with file vault [closed]
I want to know if there are any limitations that are imposed on you when you enable home folder encryption in ubuntu.
Example, in the mac file vault, at least on Snow Leopard, time machine, and ...
3
votes
2answers
956 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 ...
0
votes
1answer
492 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
140 views
How do shared hosts protect different sites?
I host all my websites from a single Linode VPN, and am about to sell some limited space of my Linode to a friend to host their new blog (it's going to be a simple wordpress blog).
It'll simply be ...
5
votes
4answers
3k 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 ...
11
votes
5answers
674 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.
...
12
votes
6answers
791 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 ...
4
votes
2answers
1k 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 - - ...
31
votes
2answers
3k 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 ...
7
votes
5answers
1k views
Browsing on a USB OS (Linux) safe from malware?
Let's say I have a computer. It's a personal computer - the one you'd typically find in homes. In this scenario, it's running Windows XP SP3, although it could run 7, Vista, etc.
I have a USB drive ...
1
vote
1answer
269 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 ...
4
votes
2answers
210 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 ...
2
votes
0answers
324 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 ...
18
votes
4answers
3k 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
337 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
352 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 ...
15
votes
5answers
1k 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 ...
42
votes
8answers
6k 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 ...
