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YoLinux: List of Linux Security Audit and Hacker Software Tools


It is important for Linux users and System administrators to be aware of the tools hackers employ and the software used to monitor and counter such activity. I actually like to use many of the following tools to test the integrity of my servers.

Also see the YoLinux Internet Security Tutorial (secure Linux configuration tutorial)

Security Audit Tools:

Perform a "Security Risk Assessment" on your system with the following tools.

System Audits:

  • Chkrootkit (YoLinux tutorial) - Scan system for Trojans, worms and exploits.
  • Root kit detection:
    • checkps - detect rootkits by detecting falsified output and similar anomalies. The ps check should work on anything with /proc. Also uses netstat.
    • Rootkit hunter - scans for rootkits, back doors and local exploits
    • Rkdet - root kit detector daemon. Intended to catch someone installing a rootkit or running a packet sniffer.
  • fsaudit - Perl script to scan filesystems and search for suspicious looking directories
  • COPS: Computer Oracle and Password System - UNIX security checks. Programs and shell scripts which perform security checks. Checks include file and directory permissions, passwords, system scripts, SUID files, ftp configuration check, ...
  • SARA - Security Auditor's Research Assistant - network security vulnerability scanner for SQL injections, remote scans, etc. (follow-on to the SATAN analysis tool)
  • Tiger Analytical Research Assistant (TARA Pro) - Commercial support

Network Vulnerability Audits:

  • Nessus (YoLinux tutorial) - Remote security scanner - This is my favorite security audit tool!! Checks service exploits and vulnerabilities.
  • OpenVAS: Open Vulnerability Assessment System. A branch of Nessus which is more free of licensing restrictions
  • Argus - IP network transaction auditing tool. This daemon promiscuously reads network datagrams from a specified interface, and generates network traffic status records
    Argus 2
  • InterSect Alliance - Intrusion analysis. Identifies malicious or unauthorized access attempts.
  • Linuxforce: AdminForce CGI Auto Audit - CGI script analyzer to find security deficiencies.


Application Security Audit:

  • Gauntlt - app security tests. Can be integrated with Continuous Integration (CI) builds
  • PortSwigger.net: Burp - Coverage of over 100 generic application vulnerabilities, such as SQL injection and cross-site scripting (XSS), and all vulnerabilities in the OWASP top 10
  • Mozilla.org: Firefox browser security Plugins:
    • Mozilla: HackBar - web-app security tests for sql injections, XSS holes, Broken Authentication and Session Management and site security
    • Tamper Data - Trace and time http response/requests. Security test web applications by modifying POST parameters.
  • OWASP - Open Web Application Security Project
  • Watabo - security tool for semi-automated testing of web applications

Port Scanners:

Used to identify computer network services available for exploit.

  • nmap - Port scanner and security scanning and investigation tool
    • NmapFe++ - GUI front-end to NMAP
    • KNmap - KDE front-end
    • pbnj - Diff nmap scans to find changes to systems on the network.
    • nmap3d - nmap post processing to 3-d VRML
    • nmap-sql - log scans to database
    • Gremwell MagicTree - processes NMap and OpenVAS output to generate a report. Requires OpenOffice.
  • portscan - C++ Port Scanner will try to connect on every port you define for a particular host.
  • pof - passive OS fingerprinting.
  • Web/http scan:
    • Nikto - web server scanner. CGI, vulnerability checks. Not a stealthy tool. For security tests.

Portscanning Information:

Network Sniffers:

Linux Tools for Network Examination.

  • DSniff - network tools for auditing and penetration testing.
  • Wireshark - full network protocol sniffer/analyzer
  • IPTraf - curses based IP LAN monitor
  • TcpDump - network monitor and data acquisition
    • VOMIT - Voice Over Mis-configured Internet Telephones - Use TCP dump of VOIP stream and convert to WAV file.
      Cisco Call Manager depends on MS/SQL server and are thus vulnerable to SQL Slammer attacks.
  • KISMET - 802.11a/b/g wireless network detector, sniffer and intrusion detection system.
  • DISCO - Passive IP discovery and fingerprinting tool. Sits on a segment of a network to discover unique IPs and identify them.
  • Yersina - Framework for analyzing and testing the deployed networks and systems. Designed to take advantage of some weakness in different Layer 2 protocols: Spanning Tree Protocol (STP), Cisco Discovery Protocol (CDP), Dynamic Trunking Protocol (DTP), Dynamic Host Configuration Protocol (DHCP), Hot Standby Router Protocol (HSRP), IEEE 802.1q, Inter-Switch Link Protocol (ISL), VLAN Trunking Protocol (VTP).
  • YoLinux.com List of network monitoring tools and example tcpdump sessions

Hacker Tools:

Password crackers:

(can also be part of a vulnerability audit)

  • John the Ripper - weak password detection. crypt, Kerberos AFS, MS/Windows LM, ...
  • Rainbow CRACK - password hacker, RainbowCrack uses time-memory tradeoff algorithm to crack hashes. It differs from brute force hash crackers.
  • Medusa - speedy, massively parallel, modular, login brute-forcer


Exploit framework:

  • MetaSploit - Exploit launcher, test and development tool

Other Links:

  • InfoSysSec.org: Hacking howto
  • hping - command line TCP/IP packet assembler/analyzer. Supports TCP, UDP, ICMP and RAW-IP protocols, has a traceroute mode, the ability to send files between a covered channel, ...
  • hping2 - Can be used to performs a lot of tasks, like testing of firewall rules, (spoofed) port scanning, ...

Security Infrastructure Software Tools:

Commercial Vendors:

Online Web Based Tools:

Cloud Computing - AWS Security Tools:

Software Updates and Security fixes:

Forensic and Data Recovery Tools:

Anti-Virus Software:

This has typically been the domain of the Microsoft Windows and Outlook products and NOT Linux but Linux administrators running SAMBA file servers often must be aware of these viruses. There are according to Symantec 68 Linux specific viruses and worms including the Ramen worm which attempts to attack unpatched rpc.statd, wuftpd, and LPRng.

Anti-Virus products:

Virus info:

Virus email alert:



How to bait and catch the evil hackers:

DoD/DoE NISPOM Chapter 8 computer security configuration for Linux:

NISPOM (National Industry Security Program Operating Manual) chapter 8 is a computer security requirement developed by the US DoD (Department of Defense - US) and DoE (Department of Energy) and published by the DSS (Defense Security Service) which US defense contractors are required to meet when processing classified data on computers in a classified environment. Linux as issued by major distros defaults do not meet this requirement. Use the following software packages/configurations:

  1. Use central authentication server (LDAP or NIS) with the proper security policies. See YoLinux LDAP authentication tutorial.
  2. Meet reporting requirements: This auditing and reporting requirement can be met using Snare. This requires a kernel patch (or use of one of the kernels [RHEL3 or RHEL4] downloaded from the Snare home page.) and the running of a Snare audit daemon. It meets C-2 reporting requirements and records logins/logoffs, file and directory access, access denial, ...
    Newer Linux distributions running auditd (RHEL4, FC3+) can get compliant results.
    Intersect Alliance: Snare project.
  3. Grant admin privileges without giving root password. Granular delegation of root privileges. File and directory access control. Symark.com: PowerBroker
  4. Virus scanner. (See above list)

Standards and Security Certification:

  • ISACA.org - The Information Systems Audit and Control Association & Foundation
  • CISA - Certified Information Systems Auditor
  • COBIT - Control Objectives for Information and related Technology


Book imageBooks:

"Hacking Linux Exposed"
by Brian Hatch, James B. Lee, George Kurtz
ISBN #0072225645, McGraw-Hill (2nd edition)

From the same authors of "Hacking Exposed".

"Maximum Linux Security: A Hacker's Guide to Protecting Your Linux Server and Workstation"
by Anonymous and John Ray
ISBN #0672321343, Sams

Covers not only audit and protection methods but also investigates and explains the attacks and how they work.

"Network Intrusion Detection: An Analyst's Handbook"
by Stephen Northcutt, Donald McLachlan, Judy Novak
ISBN #0735710082, New Riders Publishing
"SSH, the Secure Shell : The Definitive Guide"
by Daniel J. Barrett, Richard Silverman
ISBN #0596000111, O'Reilly & Associates
"Computer Security Incident Handling Step by Step"
by Stephen Northcutt
ISBN #0967299217
"Snort 2.1 Intrusion Detection, Second Edition"
by Jay Beale, Caswell
ISBN #1931836043, Syngress
"Ethereal Packet Sniffing"
by Angela D. Orebaugh, Gilbert Ramirez, Ethereal.com
ISBN #1932266828, Syngress
"Nessus Network Auditing (Jay Beale's Open Source Security)"
by Renaud Deraison, Noam Rathaus, HD Moore, Raven Alder, George Theall, Andy Johnston, Jimmy Alderson
ISBN #1931836086, Syngress
"Security Assessment: Case Studies for Implementing the NSA IAM"
by Russ Rogers, Greg Miles, Ed Fuller, Ted Dykstra
ISBN #1932266968, Syngress
"Network Security Assessment"
by Chris McNab
ISBN #059600611X, O'Reilly
"A Practical Guide to Security Assessment"
by Sudhanshu Kairab
ISBN #0849317061, Auerbach Publications
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