Securing Linux systems and applications; understanding Linux security features.

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2
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1answer
119 views

NMAP Scan Returns Odd OS Detection [closed]

I am new to NMAP but I was using it to troubleshoot some issues I have been having. I ran a scan on a device and I know the device runs some sort of Linux or Ubuntu OS and I was attempting to figure ...
1
vote
2answers
239 views

VMware VM run on insecure OS

I run VMware with Linux through my Windows OS. I want to use the Linux VM for online transactions. Is it possible for a virus, spy or worm to attack my Linux VM from the Windows host? Is my Linux ...
0
votes
0answers
60 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 ...
0
votes
0answers
35 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 ...
27
votes
11answers
6k views

One liner to create passwords in linux?

How do you create a readable password using bash with one line? What if i'm looking for 128 bits of entropy? EDIT By readable I mean the 94 printable ascii characters (without space). It can use ...
9
votes
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 ...
1
vote
1answer
118 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
vote
1answer
52 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. ...
4
votes
1answer
602 views

Pros and cons of disabling TCP timestamps

So, lynis informs me that I should unset net.ipv4.tcp_timestamps. I know that's a bad thing because an attacker could figure out which updates that require restarting the machine I haven't applied, or ...
2
votes
3answers
824 views

Apparmor system-wide security — white-listing

I want to only white-list applications that can run on my system using Apparmor, I know it is used to confine applications/programs based on their path names, but what I need is to contain those ...
19
votes
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 ...
1
vote
2answers
456 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
votes
3answers
103 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 ...
0
votes
1answer
261 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 ...
5
votes
3answers
521 views

Current industry standard key management solution for web app on linux host

The scenario: Data is sent to an application server and you want to selectively encrypt some data before sending it to a DB server for storage. All servers run some linux distro. This is a relatively ...
1
vote
0answers
31 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 ...
2
votes
1answer
149 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 ...
20
votes
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 ...
5
votes
2answers
411 views

Decrypting SSL using Wireshark on Linux vs Windows

I'm working on decrypting my own traffic that gets sent through Wireshark and I've been following this guide for reference. I have been using the SSLKEYLOGFILE environment variable and I can get the ...
1
vote
1answer
150 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 ...
0
votes
1answer
50 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 ...
1
vote
0answers
28 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 ...
2
votes
1answer
227 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
38 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
52 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
495 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
82 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
511 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 airmon-...
2
votes
1answer
44 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
88 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
79 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
143 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
85 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
0answers
66 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), sync:x:5:0:sync:/sbin:/bin/...
0
votes
0answers
63 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
62 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 process/...
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
171 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
119 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
28 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
955 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 ...
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 reasons ...
4
votes
1answer
45 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
81 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
427 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
28 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
180 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 ...
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 ...