Securing Linux systems and applications; understanding Linux security features.

learn more… | top users | synonyms

4
votes
2answers
9k views

Test firewall rules (Linux)

I have a question about how to test the firewall rules. To be more specific, for academic purpose I have to set up a machine which will accept all kind of packets o a specific interface. I added an ...
7
votes
2answers
4k views

Do these regex show that I was hacked?

What do these regex commands mean? I found them when I ran the history command: grep --include=\*.php -rnw . -e "update.creditcard" grep --include=\*.php -rnw . -e "e41e" grep --include=\*.php -rnw . ...
37
votes
9answers
5k views

Is full disk encryption on a server in a secure data center pointless?

I am having a debate with several people regarding how much protection full disk encryption provides. dm-crypt is being used to encrypt data which is required by my company to be encrypted at rest. ...
7
votes
1answer
253 views

Linux Plausibly Deniable File System

Is there any way to encrypt a linux filesystem in such a way to maintain plausible deniability? E.g. "Hidden OS support," the way Truecrypt and Veracrypt work, they only support Windows OS due to low ...
1
vote
0answers
48 views

Can high network usage be detected and prevented in Tor? [closed]

I've already asked this question here but as of yet it has no views/answers. I was wondering if there is any way for Tor to detect high network usage in the context of transferring large files using ...
5
votes
1answer
385 views

Does Linux kernel use DEP for kernel memory?

Does the Linux kernel use DEP internally for its kernel memory? In other words, does the Linux kernel take care to ensure that, when the kernel is executing (in kernel mode), every executable ...
3
votes
2answers
119 views

What are the security risks in leaving 'sudo' inside my production code?

I have a script that can only run successfully with root permissions But in development it's really hard to run with root permissions (in my development environment) so I add 'sudo' when ever it's ...
2
votes
2answers
145 views

Questions regarding Bad USB exploit

I own a Netbook and my external DVD Drive is possibly infected with Bad USB. If I install Ubuntu using this infected DVD drive, could my system be taken over during installation process or later when ...
3
votes
1answer
106 views

Decryption using GRUB and TPM

I'm trying to plan security routine for my new Linux install and few questions came up during searching for solution which meet my needs. Is it possible to use private key from TPM in GRUB to ...
16
votes
8answers
1k views

Is it possible to prevent a file type from being determined in a Linux system?

I have several files on my Ubuntu system, which are LUKS encrypted partitions. For my own shame up to this day I thought that simply changing binary file's extension will be enough to hide what a file ...
16
votes
3answers
820 views

ISO27001 and Linux/Ubuntu

My company has an ISO 27001 certification. They provided me a new laptop with Windows 8 OS in it. I asked if I can have a Linux/Ubuntu OS installed, they said that it is not possible due to the ISO ...
1
vote
3answers
90 views

Protecting Uploaded Confidential Files [closed]

We have a web application in Linux (App A) using PHP and Zend and another in Windows using Asp.net C# (App B). They both access the same database. App B is for internal use only while App A can be ...
1
vote
2answers
50 views

Detect SSH InBound / Oubound Connections

I'm noodling with the idea of managing SSH connections on Linux server using a program (not sure what it will be written in yet) that monitors inbound and outbound connections. Is there a way to ...
1
vote
1answer
77 views

Securely hide a directory from the OS using java?

I have a project to do for my master's degree and I need to do a Java app which loads a file (read some attributes and copy the file to a working directory), basically any file, and make the working ...
5
votes
2answers
2k views

Security of LXC compared to OpenVZ

For years, I'm now using OpenVZ on my server, but support discontinued for Debian and Ubuntu, current releases seem to focus on LXC now, which is not a bad idea from the point of comfort. But what ...
2
votes
1answer
48 views

Is it possible to use obtained wildcard certificate on more than one server?

We are using two Debian servers in our company (with apache 2 as httpd) and our services are split between those two of them. One server has the website, the other has some minor sites under ...
3
votes
1answer
972 views

How configure tomcat 7 SSL to use AES-NI?

My server has AES-NI and I would like tomcat 7 to make use of this but I am not really sure how to make that happen or where to even start looking. I am quite familiar with tomcat administration, and ...
10
votes
2answers
293 views

Bootstrapping an EC2 Spot Instance

I'm considering using EC2 Spot Instances in an automated fashion (ie create a script that will request EC2 Spot Instances that will run unattended). For this specific use case, I'm happy to lock down ...
-4
votes
1answer
578 views

Kali Linux Veil-Evasion install problem [closed]

I can't install Veil-Evasion. I have this error: Installing (Wine) i386 Binaries Reading package lists... Building dependency tree... Reading state information... Package wine-bin:i386 is ...
12
votes
1answer
1k views

How to check if my USB stick firmware can be rewritten via the USB port?

How can I know in Linux (or otherwise), if the firmware of my USB flash drive can be rewritten using the USB port (when sticking it in an USB port)? Eg. for a cheap EMTEC 16GB. I was thinking about ...
1
vote
0answers
66 views

Why use oddly compiled ELF files for Linux malware?

I ran file on some Linux malware ELF files that I've acquired over the last couple of years. I noticed some oddities: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked, for ...
2
votes
2answers
113 views

Is writing to /dev/null secure?

I am working on a web-service based crypto project in JAVA. The basic idea is for the client to send a SOAP request to a servlet to encrypt data. For data transmission I am using MIME/data-handlers ...
1
vote
0answers
83 views

Volatility Framework 2.4 - No suitable address space mapping found [closed]

I made some dumps with different formats (.DMP and some file made by LiveKD utility) in Windows 8.1 x64 OS. The first one is a explorer.exe dump file which was created by TaskManager->Create Dump File ...
1
vote
2answers
51 views

How to use Aircrack-ng when knowing part of the password?

Let's say I know the password starts with "1234" and after that there is a commonly used password. I would like to use the word list I have for the second part of the password, but to include somehow ...
0
votes
0answers
39 views

Strange SECCOMP entries for sshd in audit log

I've posted this over at ServerFault but haven't received a response over there. I'm not a security professional, but I'm curious as to what kind of attack this might be and how the attackers might be ...
1
vote
1answer
42 views

RDRAND in Intel Celeron CPUs under Linux

Is there any reason to believe that the hardware RNG in an Intel Celeron CPU is more unreliable than in other CPUs? Can someone confirm that what Linus Torvalds says is true, namely that Linux does ...
2
votes
1answer
480 views

How to measure the integrity of the OS (Linux)?

I am working on a project which requires Integrity measurement of OS (Linux). One way to do that is using IMA but I am not sure if it fits in the scenario below. The scenario of the project is some ...
2
votes
1answer
156 views

Dump linux password in clear text

Is it possible to dump a Linux password in clear text format? In Windows it is possible to do so using "Windows Credential Editor".
2
votes
2answers
71 views

How to overwrite ebp on stack alignment?

I want to exploit a simple program #include <stdio.h> #include <string.h> int main(int argc, char** argv) { char buf[128]; strcpy(buf, argv[1]); return 0; } The disassembly ...
0
votes
0answers
87 views

How 'private' is my setup?

I'm currently running QubesOS (so essentially a virtualized Fedora operating system), which I use to access an offshore VPS through I2P (using garliccat). I then route all my traffic through the VPS ...
15
votes
2answers
4k views

Security Concerns with X11 Forwarding

What are some of the security concerns and reasons either for or against allowing X11 Forwarding. I have generally taken an approach of not allowing it under the blanket guise of security. Recently, ...
0
votes
0answers
18 views

At OpenSSH ssh server side key files has 0 data. I would like to know the reason for it

I am using the Monta Vista Linux. In this recently i have observed the ssh keys files has 0 data due to which the keys were not generating and i am not able to login to machine via ssh because of key ...
2
votes
3answers
362 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 ...
6
votes
1answer
169 views

Does the new Fedora package manager allow unauthorized installations?

I just upgraded to Fedora 22. The biggest change from the previous version is that the yum package manager is now replaced with dnf. One change I've noticed is that if you try to execute a command ...
4
votes
1answer
86 views

Desktop Flickers Past Lock Screen

I'm using Fedora 22 with Gnome 3. I have a password set for my user account, so when my laptop awakens from sleep, I am presented with the lock screen and must enter my password before getting to my ...
1
vote
0answers
26 views

Linux PAX, execute and write permissions

I would like to know what happens when a section of a program is compiled with both execute and write permissions and PAX is enabled on the system? Is the program successfully loaded? Is the section ...
2
votes
2answers
51 views

Are there any dangers in sharing ifconfig information publicly?

If I were to share my ifconfig information from Linux publicly, is there any possible danger associated with this action?
-5
votes
1answer
100 views

How to use wordlist [closed]

I have downloaded a wordlist from https://crackstation.net/buy-crackstation-wordlist-password-cracking-dictionary.htm The size of the wordlist is 4.2 GiB (compressed) or 15 GiB (uncompressed) The ...
5
votes
5answers
885 views

How secure is it to keep the salt with the password hash? [duplicate]

In Linux we have the salt just next to the password hash in the /etc/shadows file. I always hear that salt value prevents hashed passwords from being cracked by brute force methods. But if somehow we ...
3
votes
3answers
466 views

Error message in Apache logs shows /bin/bash and wget

I am wondering if my server is compromised or not I just looked at my log and seen the following line in there [Thu May 14 09:10:42.587255 2015] [autoindex:error] [pid 3422] [client ...
0
votes
2answers
118 views

How to make data in hard disk unrecoverable on linux [duplicate]

I need to wipe completely the data on my hard disk so it's unrecoverable. I'm actually using Linux, i have seen this command on the web, but I don't know if its secure. shred -zvn 35 /dev/sdb
5
votes
1answer
128 views

Video site requests Adblocker to be shut off, next day I have 3 “weird” bookmarks

I was on a site trying to view a video and the site requested that I turn off my adblocker to view the video. So I did and then the next day I noticed that I had 3 "weird" bookmarks in my bookmark ...
0
votes
1answer
83 views

When can the exploit for CVE: 2006-7098 be used?

I'm studying the vulnerabilities of an old version of Apache, the 1.3.34. And I don't quite understand in what exact situation the CVE 2006-7098 vulnerability can be exploited. The README included in ...
4
votes
1answer
64 views

Can BTRFS provide authentication on an encrypted disk?

One of the problems of disk encryption is providing authentication. An attacker with access to the ciphertext can modify the ciphertext at will without consequence. Given, this isn't a likely attack, ...
0
votes
0answers
82 views

TPM Command Line Tools

I am trying to create a key storage hierarchy on TPM (Trusted Platform Module) on Linux (CentOS 6.4). The most commonly recommended TPM tool suite on Linux is TrouSerS. However, the command line suite ...
7
votes
2answers
3k views

How to pass PCI DSS 2.0 anti-virus requirement (5.1) on Linux?

PCI DSS 2.0 Requirement 5.1 states: 5.1 Deploy anti-virus software on all systems commonly affected by malicious software (particularly personal computers and servers). This requirement ...
0
votes
2answers
79 views

PCI-DSS, what is the best distro? [closed]

What is the best distro of Linux to get PCI-DSS compliant? I am using Debian 8 because I think Debian is one of the most stable versions, but it seems not to be enough, I am struggling with a lot of ...
3
votes
1answer
155 views

How to check whether my USB flash drive was infected by the BadUSB

After failing to check whether my USB stick firmware can be rewritten AT ALL, I want find out, whether it WAS rewritten when I sticked it in another computer. In particular the question is: how to ...
2
votes
2answers
35 views

Which software RNG for linux?

A headless server can suffer from a lack of entropy, which is a problem given that encryption needs random numbers. In the absence of a hardware random number generator (RNG) the numbers must be ...
2
votes
1answer
61 views

Security implication of non-free drivers

I was wondering what the security implications are of using non-free drivers on a linux laptop. Especially for graphics and wifi.