100 Best Open Source Security Tools

Whether you’re a network administrator, security professional, or an end user, it’s important that you keep your system clean and secure. There are a variety of high quality open source security tools available, and many of them are free. Check out this list to find 100 of the best of them.

General

These tools offer a variety of useful security functions.

Untangle: Untangle will provide you with spam, virus, and spyware protection, as well as Web filtering, firewall, and more.
Network Security Toolkit: This tool combines a variety of open source apps that will help you stay on top of traffic, intrusions, and more.
Bastille Linux: With this tool, you’ll answer questions about your security, and will get a custom lockdown for your machine.
OSSIM: OSSIM brings together a number of open source security tools to give you network details and stay on top of intrusions.
ProShield: Use Proshield to get a scan of your system for up to date software and malware.
Hardened Linux: This Linux distribution will help you improve your security.
eBox Platform: Use this network management framework for content filtering, proxy, firewalls, and more.sa
Kismet: Kismet offers wireless network detection, intrusion detection, and packet sniffing, all in one.

Monitoring

With these tools, you’ll get constant monitoring of your security.

Nessus: Use this free scanner to stay on top of your vulnerabilities.
Nagios: This host and network monitoring tool will let administrators handle outages before clients and users are affected.
AWStats: Use AWStats to get a look at attacks on your server.
Honeytrap: With this tool, you’ll get advanced warning about attacks.
The Multi Router Traffic Grapher: Use this tool to monitor your SNMP network devices.
Snort: Snort is an incredibly effective intrusion detection system.
BASE: This tool works well with Snort to make your intrusion detection data more easy to understand.
Internet Secure Access Kit: This suite will help you restrict and monitor access on your network.
Afick: Afick will help you stay on top of changes to your system.
Network Security Analysis Tool: Use this tool to scan your network for vulnerabilities.
Nagios: This program will monitor your enterprise network services, environmental factors, host resources, and point out potential vulnerabilities.
JbroFuzz: With this tool, you can test the integrity of your network.
Yet Another Security Monitoring Interface: This web based application will help you take a look at the data flow in your router.
ettercap: Ettercap will monitor your LAN, staying on top of content, live connections, and other potential attacks.
Metasploit: Often used by hackers, you can test your system with this tool.
SNARE: Make use of this tool that collects and analyzes your event log data.
Nikto: Nikto will scan your web servers for problems and dangerous files.

Email & Spam

Use these tools to keep your email secure.

Spam Assassin: This anti-spam tool will help you keep your email neat and clean.
Tiger Envelopes: This email encryption tool works with a variety of programs, including Thunderbird and Outlook.
Anti-Spam SMTP Proxy Server: Use this application to filter out spam and viruses.
Spamato: With this client-side spam filter, you can keep the junk out of your Outlook, Thunderbird, and other popular email clients.
phPOP3clean: Use this scanner to look for worms, spam, blacklisted words, as well as blacklisted domains.
Thunderbird: This open source email program has a variety of tools for keeping spam and viruses at bay.
Mailsaurus: This email client will encrypt all of your data so that no one can read your email.
MailCleaner: With this filtering application, you can keep the spam and viruses out.
Web Stat: Want to know how much spam you’re blocking? Use this tool that will display your level of blocked spam graphically.

Anti-Virus

With these tools, you can protect your computer and network from viruses.

FullControl: This software will stay on top of all the programs running on your computer and verify their integrity.
ClamAV: Make use of this excellent antivirus tool to keep your machine free of viruses.
ClamWin: If you want to take advantage of ClamAV on your Windows machine, make use of this tool.
Moon Secure Antivirus: This antivirus scanner also features a firewall.
Winpooch Watchdog: Winpooch will stay on top of spyware, trojans, and viruses.
Softlabs AntiVirus: Using this antivirus tool, you can scan your email for phishing and viruses.

Firewall

Use these firewall tools to keep unwanted intruders and items out of your system.

SELinux: Using SELinux, you can set mandatory access control features for Linux.
m0n0Wall: This tool offers both firewall and VPN.
ShellTer: ShellTer offers a firewall with SSH protection.
Endian Firewall Community: Use this tool to turn an old PC into an appliance that provides a variety of security functions.
FirewallPAPI: This system will stay on top of your network traffic.
SmoothWall Express: Use SmoothWall to turn a PC into a firewall appliance for your network.
WIPFW: Use this tool to monitor and filter packets entering your network.
Fail2Ban: Fail2Ban will stay on top of log files and look for failure prone IPs, which will be blacklisted.
Vyatta: Turn to Vyatta to get an enterprise class firewall for free.
ISP-FW: With this server side firewall application, you can get packet filtering and monitoring.
Firewall Builder: This tool will make it easy to establish rules for your firewall.
AppArmor: Create policy-based profiles to control access to applications with AppArmor.
Firestarter: Make use of this firewall if you want to get your firewall security up and running in a hurry.
Linux Embedded Appliance Firewall: This firewall tool will help you shore up your security.
IPCop: With this tool, you can turn any PC into a firewall appliance to get your network secure.

Files & Data

Keep your files, data, and transfers secure with these tools.

Darik’s Boot and Nuke: If you want to wipe out a hard drive, just boot up with a disk containing this tool.
Packet Generator: Use this tool to optimize the routing schematics for your network.
Paros: Paros intercepts data, offering a way to evaluate web application security.
Cyberduck: With this tool, you can transfer files to remote computers and networks.

WinSCP: Use this SFTP and FTP client for secure file transfes.
Eraser: This tool will eliminate files by overwriting them several times, so that they can’t be read using digital forensic tools.

Encryption & Cryptography

Make use of these encryption and cryptography tools to stay secure.

KeyCzar: Use this toolkit to make cryptography easier to use in applications.
Cameloid: Keep your voice connections safe with this encryption tool.
GNU Privacy Guard: This encryption tool uses a number of different encryption algorythms.
TrueCrypt: Use TrueCrypt to encrypt a partition or drive, or create a virtual encrypted disk within a file.
Cryptonit: Secure your files and address books with this encryption tool.
Checkpoint Commander: This tool will both encrypt and completely erase your files.
AxCrypt: AxCrypt is a simple encryption tool that will allow you to encrypt files with just a few clicks.
Magikfs: You can hide your files using this tool with a steganographic filesystem.
FreeOTFE: This tool will create secure virtual drives on your PC.
Cryptology: Cryptology offers encyption that integrates into Windows Explorer right-click menus.

Passwords

With these tools, you can keep your passwords handy and secure.

KeePass: Use this password safe to keep all of your passwords safe and encrypted.
CiphSafe: This tool will encrypt your usernames and passwords for popular Internet websites.
Password Safe: Password Safe will help you create strong passwords and can store multiple password databases.
Keep It Secret! Keep It Safe!: With this tool, you can store your important usernames and passwords in an encrypted file.

Remote Access

Use these tools for secure remote access.

OpenSSH: With this tool, you can safely operate a remote host.
Stunnel: Stunnel will encrypt your TCP connections inside SSL connections.
OpenVPN: Get safe VPN access using this tool.
SSL-Explorer: This web-based VPN server will allow you to use a standard browser.
Open SSL: This tool uses Transport Layer Security and Secure Socets Layer protocols to keep you safe.
strongSwan: strongSwan offers an IPsec-based VPN tool for Linux.
PuTTy: Get remote access with this telnet/SSH client.
UltraVNC: Use this tool to get safe and secure remote access.

Networking

These tools will help you operate a more secure network.

Nmap: Nmap will help you stay informed of all of the hardware that is connected to your network.
Wireshark: Using Wireshark, you can take a look at all of the traffic that passes over your Ethernet network.
Bro: Bro offers network intrusion detection that will passively monitor your network traffic for anomalous traffic behavior.
Network Simulator and Network Animator: With this tool, you can test your network flow to prevent bottlenecks and promote better routing.
OCS Inventory NG: This tool will provide you with a list of hardware and software on your network.
Netcat: Netcat is a simple utility that will help you read and write data across UDP or TCP network connections.
Angry IP Scanner: This tool will scan IP adresses and ports on your network.
Ossec HIDS: With this intrusion detection system, you’ll find out when your network is being attacked.
TcpDump: If you’re looking for a light, secure packet sniffer, check out this tool.
The Network Visualizer: Get graphic information on your network activity using this tool.

Miscellaneous

Check out these tools for even more open source security applications.

Tripwire: Find out when changes are made to your system by using this tool.
Firefox: A very popular web browser, Firefox offers a variety of secure options and add ons.
The Sleuth Kit: With this kit, you can recover deleted files.
JAP: This tool will allow you to browse the Internet anonymously.
iSAK: Using this tool, you can filter out specific types of websites.
Advisory Check: This tool will read RSS and XML security feeds to monitor the security of the software you’re using.
Babel: Babel will let you know about all of the security flaws that you have in your system.