Securing Linux systems and applications; understanding Linux security features.

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CTF - Security code audit

I am playing a CTF wargame and unfortunatley got stuck at this level. Want to "crowdsource" it. No need for complete answer, but hints would be enough. How can I: make strcmp to be 0 (evaluate if ...
4
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2answers
115 views

Is there a reason why /proc/interrupts is world-readable?

Reading this recent research paper on how to use information from /proc/interrupts to attack a system, I was wondering whether there is a particular reason why /proc/interrupts is world-readable. ...
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1answer
24 views

Decypt des-sunos5.7 ecncrypted file by using OpenSSL in Linux

One of the shell scripts in our old Solaris 10 server uses below command to decrypt a file. des-sunos5.7 -d -u -k password enc_filename.tar.gz dec_filename.tar.gz Now we are migrating to RHEL 6 and ...
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0answers
30 views

Technique to put highest privileges backdoor on compromised Linux machine and how to remove it? [on hold]

What are the techniques attackers use after they compromised a Linux server to put a highest privileges backdoor to get access back in future? How can I track this type of backdoor and remove it?
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25 views

Why isn't ettercap working

I am working on an ARP poisoning/browser redirection project with Ettercap but even if I follow all the steps right it still doesn't work. I tried disabling firewalls too. What I do is: Start ...
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18 views

(kali SET)Why not connet another network and Why not write keylogger in (.txt) ??? [on hold]

SET version 7.1.2 [] Cloning the website: https://login.facebook.com/login.php [] This could take a little bit... The best way to use this attack is if username and password form fields are ...
3
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1answer
133 views

Air-gap implementation for personal computer use

I recently read over Bruce Schneier's article on setting up an air-gapped computer and am looking to improve my setup (compared to my current "use one Windows PC for everything" model). The main ...
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2answers
56 views

Safe to connect a USB to Linux?

A "friend" offerred me a USB with files. I plugged it into my Ubuntu (version 12 or 14, don't remember) PC and an error appeared (don't remember exactly what was written..). So I wasn't able to browse ...
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1answer
24 views

Using virtual server for backing up files

I've purchased a virtual server which I need to run some custom tools every once in a while. I actually don't use any server features of my virtual server, I really just need a Linux machine which is ...
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1answer
32 views

How are DNS requests sent when using ovenvpn? Are they encrypted?

I use openvpn in thru the gnome network manager. When my computer is connected to the vpn do DNS requests look like they come from the vpn exit ip or from my real ip? Are the DNS requests sent in the ...
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0answers
24 views

Linux server just as RAMdisk [migrated]

I want to setup an anti-forensic Linux server to protect my users. My aim is to have the Linux distro and everything inside of it running from RAM, never storing anything permanently. It is possible ...
3
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1answer
80 views

Hidden service security SSH

Pretend I have a Tor hidden service. For ultimate security I would firewall the internet entirely, except for Tor, to try to reduce IP address leakage and other security risks. My problem is how ...
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0answers
26 views

How to secure Linux terminal with Google Authenticator? [migrated]

How to secure Linux terminal with Google Authenticator for root access and login?
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0answers
3 views

Subuser Docker firefox image [migrated]

I followed all the steps to create subuser given on subuser.org I am not able to create firefox image and not able to restrict the access to the Downloads folder as given in the video and ...
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0answers
16 views

change password or username of Essid and key automatically [closed]

I use some script to scan some ip addresses and I cracked the password and username of their router home page. Can I change their password or username of Essid and key pass automatically by using ...
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0answers
29 views

Why there is no shell prompt by exploiting this script?

I tried to get a shell prompt in the following vulnerable code, I think that I found the vulnerability, actually it is a simple stack buffer overflow, but now I have a problem with exploiting the ...
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0answers
14 views

Process of auditd -s enable/disable persists for a long time

I have setup auditd on my system, with some basic rules from CIS Benchmark paper and the following auditd.conf file: log_file = /var/log/audit/audit.log log_format = RAW log_group = root ...
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5answers
2k views

Can we trust the information displayed by the linux utility commands for a vulnerable machine?

After checking a vulnerable linux machine for rootkit and deleting them, we need to get some informations about the process , port ,incoming or outgoing connections... , using some useful commands as ...
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1answer
62 views

How does this privilege escalation vulnerability on Elastix work?

Here is a privilege escalation vulnerability on Elastix: # id # uid=100(asterisk) gid=101(asterisk) # sudo nmap --interactive # Starting Nmap V. 4.11 ( http://www.insecure.org/nmap/ ) # Welcome to ...
1
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1answer
39 views

Is there a functional difference between `chage -M 99999`and `chage -M -1`on Linux?

My group just requested a security scan on some of our development systems and were informed that a number of system type accounts were insecure because the password did not have a maximum time limit. ...
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2answers
332 views

How to prevent the latest ImageMagick vulnerability?

According to the CVE-2016–3714 there are a some vulnerabilities in the ImageMagick program (4 packages) : Insufficient filtering for filename passed to delegate's command allows remote code ...
2
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3answers
57 views

Mutual authentication of SFTP server

We can use public/private key pairs for client authentication when connecting to a SFTP server. Can we also have mutual authentication so the client also verifies a public key from the server? Both ...
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0answers
25 views

Can linux cgroups and namespaces assist hiding malware?

Reading about sandboxing/security possibilities I was looking a bit into cgroups and namespaces and asked myself: How do I know that my linux root account is indeed the real root account and not ...
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1answer
83 views

Raspberry Pi IDS/FireWall - Should I? [closed]

I was excited to setup an IDS/FireWall with my new Raspberry Pi on a standard home network. Reading threats to SSH and Linux, now I am not so sure. Setup by an experienced amateur I'm now concerned ...
1
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1answer
108 views

Is it possible to use the Linux “echo” command maliciously?

While testing a web application today, I came across a function that passed arguments to dig in linux terminal. After some fiddling about I was able to pass the echo command using pipes and echo my ...
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4answers
4k views

Is VLC on Linux vulnerable to an attack from .wmv files designed to install viruses? [duplicate]

I was stupid and did not check a video file I downloaded from an untrustworthy source. It was .wmv file with no readable properties of the video. I know that .wmv videos can download viruses. What I ...
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0answers
100 views

Prevent keyloggers on Linux?

Are there any mechanisms in the Linux desktop architecture to prevent malicious software keyloggers? What would be an ideal Linux setup to make it very difficult for an attacker to install a keylogger ...
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0answers
3 views

Why ecryptfs still remain in mtab? [migrated]

I use ecryptfs for encrypted lxc container container start ok and stop ok But i see even after stop this line /var/container-lxc/face/rootfs.crypt on /var/container-lxc/face/rootfs type ecryptfs ...
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0answers
22 views

Inserting XSRF header token in Hydra

I'm trying to break a login form with Hydra. The site is built with the Angular framework, and an XSRF token must be sent through the header and through the POST request. I notice that the XSRF ...
0
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1answer
30 views

Does KDE System Tray Extra Items “Clipboard” have the same security threats as the system clipboard?

Does the clipboard under kUbuntu's KDE System Tray > Extra Items "Clipboard" have the same security threats as the system clipboard? The following articles point out the insecure nature of the ...
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6answers
4k views

Why is it considered safe to install something as a non-root user in Linux environments?

We always hear it is safe to run unknown programs as non-root users in Linux because non-root users are sandboxed from the system level and can't change anything out of their permission scope. If ...
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0answers
34 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 ...
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1answer
32 views

Defense-In-Depth With Common Security Controls

Many operating systems implement system capabilities, Posix access controls (DAC/ACLs) and mandatory access controls (SELinux), each using different underlying security controls to provide individual ...
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43 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 ...
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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 ...
3
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1answer
120 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
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2answers
53 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 ...
2
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1answer
28 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 ...
25
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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 ...
0
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1answer
79 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 ...
0
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1answer
221 views

My server was hacked and I am asked to pay to recover my files

Today I got a message when I logged on the server: Hi, please view: http://pastie.org/private/tlixxvclirxmut6djqyacq for further in ...
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1answer
41 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; ...
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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), ...
3
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1answer
63 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 ...
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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, ...
0
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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 ...
0
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1answer
50 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 ...
4
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5answers
145 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 ...
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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. ...
3
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1answer
39 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.