Securing Linux systems and applications; understanding Linux security features.

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How crypto module integrity checks mandated by FIPS 140 standard help to make Linux based appliances safer?

After browsing dracut and hmaccalc rpm package source code I found out sha512hmac utility that is used to do do integrity checks for linux kernel (and other binaries) from initramfs boot stage uses ...
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3 views

What is purpose of fipscheck utility and fipscheck library on Linux?

So I am messing around with dracut and I am trying to get my Linux system in FIPS 140 mode by passing fips=1 to my linux kernel at the boot time from grub. However, I got confused on why dracut ...
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1answer
39 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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1answer
31 views

How can I understand this extract, concerning basic heap overflow?

Unfortunately, I dont seem to understand one minor concept in the "Art of Exploitation" book, concerning heap overflow: a new root shell is being added to the passwd file. From page 168: However, ...
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Does altering the routing table to my hub defeat the purpose of a VPN?

I am running a VPN on my server with openvpn. When running openvpn I have a shell script that runs afterwards: ip rule add from 192.168.0.19 table 128 ip route add table 128 to 192.168.0.0/24 dev ...
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3answers
3k 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 ...
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5answers
66 views

Is it beneficial to run the browser from a different user account for personal devices?

On Linux, when launching the browser does it help security if I don't run it from my main user (not root, but still has my personal information in it) as follows: su FirefoxUserName -c 'firefox' ...
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Error Running command shell :TimeoutError Operation Time out

I am Testing a Payload linux/x86/meterpreter/reverse_tcp in my Test Linux network to Exploit, I got a Meterpreter Session by Metasploit using it, I tried several commands like getuid, cat and all ...
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952 views

Why does the linux XRDP module use a 512 bit RSA key?

Why does the linux XRDP module use a 512 bit RSA key? 512 bit RSA keys are broken by now. How can this be safe?
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1answer
981 views

Snort even though working properly does not report majority of rules

I have installed Snort 2.9.7.0 and it does not detect majority of attacks, such as nmap port scans, downloading exe files, opening documents containing keyword "root". I use Snort together with ...
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3answers
122 views

How can I execute shell in this CTF exercise?

I am playing a CTF wargame and unfortunatley got stuck at this level, so I want to "crowdsource" it. No need for complete answer, but hints would be enough. How can I: Make strcmp to be 0 (evaluate ...
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2answers
133 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
29 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
33 views

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

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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26 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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1answer
83 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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(kali SET)Why not connet another network and Why not write keylogger in (.txt) ??? [closed]

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 ...
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2answers
58 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
148 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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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
34 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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1answer
477 views

SQLMAP --OS-SHELL error [closed]

root@kali:~# sqlmap -u http://www.a***********.com/info.php?id=2 --os-shell _ _ _| |_____ _ {1.0-dev-nongit-20150907} | -| . | | | .'| . | || |||||,| | || |_| ...
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3answers
624 views

Removing a Redirect Virus from Fedora Linux

Despite several attempts listed below certain websites are getting redirected to a certain ad website automatically, out of the blue on linux. When some website starts redirecting to this ad website ...
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1answer
526 views

How does SELinux affect the Linux Kernel networking stack?

I'm interested in how SELinux effects the processing of packets through the networking stack. I've found the following questions and answers: Network policies under AppArmor/SELinux Filtering ...
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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 ...
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1answer
111 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 ...
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2answers
226 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 ...
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3answers
237 views

About SHA1 in default Disk Encryption in Linux

Link to the Thread: Recommended options for LUKS (cryptsetup) I wonder what's the exact difference between SHA1 and SHA512. I know that SHA512 has a longer key but I've read that it doesn't matter ...
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2answers
494 views

How exactly does this Flash malware function on Ubuntu?

In this video, an experienced Ubuntu user manages to infect his system with some sort of malware. This is the first example I've ever seen of truly successful malware in the wild aside from privilege ...
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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
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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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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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 ...
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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
90 views

How use snort with local.rules in offline mode?

I'm using SecurityOnion distro and I would to run snort on my pcap files. Is there a way to specify just one rule? I couldn't understand whether local.rules is used. How can I show only the result ...
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1answer
64 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 ...
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1answer
40 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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1answer
209 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 ...
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3answers
786 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 ...
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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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2answers
338 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 ...
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3answers
61 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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1answer
224 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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3answers
509 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 ...
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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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91 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 ...
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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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1answer
110 views

Block OS fingerprinting without using iptables?

I have a Linux machine connected to a Windows 98 PC on port 104. Now I want to block the OS fingerprinting using nmap for the windows 98 PC. I tried using iptables (blocking that particular port) but ...
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2answers
337 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 ...