The 10 Best Free Security Tools

Updated: April 30, 2009

Malware developers distribute their offerings to unsuspecting computer users at no cost. Wouldn't it be great if the tools that secured systems against such unwanted generosity, as well as other IT threats, were also free?

Fortunately, it's possible to build an impressive security arsenal without spending a cent. The Web is packed with free products that are designed to protect systems from malware, Internet attacks, device misconfigurations, and a variety of other threats and weaknesses. Many of these freeware tools aren't highly publicized and, therefore, aren't widely known. But you don't have to spend hours searching Google for free security tools — simply check out the following top 10 offerings.

MBSA (Microsoft Baseline Security Advisor) : This free tool helps Windows systems users answer the eternal question: How safe it my IT infrastructure? The advisor checks systems for common misconfigurations and missing security updates, then makes recommendations for improving safeguards in accordance with Microsoft security standards.

Nessus : This product is considered to be one of the best vulnerability scanners available at any price — and it happens to be free. The tool explores and maps network systems for potential weaknesses that could provide an open door to attackers. The Nessus client is compatible with all Linux/Unix systems. There's also a Win32 GUI client that works with any version of Windows.

AVG Anti-Virus Free Edition : Grisoft's AVG Anti-Virus Free Edition, compatible with Microsoft Outlook and Eudora, quarantines suspected virus -infected emails and scans all email traffic over POP3 and SMTP protocols.

Ad-Aware Free : This no-cost program scans computers for hidden parasites — including Trojan horses , worms and spyware — and removes them permanently. Ad-Aware Free is perhaps the most popular free security tool in Internet history, with publisher Lavasoft reporting more than 250 million downloads so far.

Ethereal : An open-source packet sniffer , Ethereal Network Protocol Analyzer supports network troubleshooting, analysis, software and protocol development. The tool is compatible with popular computing platforms, including Windows, Unix and Linux.

NetStumbler : Rogue wireless networks are now a major security threat, providing a way for attackers to enter business systems. Windows-based NetStumbler detects nearby wireless LANs based on the 802.11b, 802.11a and 802.11g standards. A thin version, MiniStumbler, runs on Windows CE-based mobile devices, allowing users to roam around business premises while sniffing out rogues.

MailWasher : Are you sick of spam clogging your employees' mailboxes? POP3-compatible MailWasher promises to filter and block spam messages while allowing legitimate email to pass through unimpeded. And it won't cost you a nickel.

Karen's Replicator : Since even the most security-conscious business will need to restore data at some point, frequent and comprehensive backups are a vital part of any security strategy. Karen's Replicator can copy files and folders to a backup storage device on either a manual or scheduled basis. The program can also distribute files across a network and automatically restore damaged or changed files on a Web server.

Snort : An open-source network IDPS (Intrusion Detection and Prevention System), Snort is a protocol analyzer that enables users to passively detect or actively block various kinds of probes and attacks. The software's detection capabilities include stealth port scans, operating-system fingerprinting attempts, buffer overflows and application attacks.

GnuPG (Gnu Privacy Guard) : This family of open-source encryption products is developed under the auspices of the Free Software Foundation's software project. GnuPG can be combined with front ends that supply compatibility with virtually any operating system — past or present.

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