Computer security is a multifaceted endeavor. Every computer needs a good antivirus program, a firewall, at some point a password manager, and at least a couple of anti-malware programs. The firewall comes first, antivirus second. They are that important. Whereas you can have two or even three anti-malware programs running different strategies simultaneously, you can only run one software firewall and one antivirus program at the same time. Otherwise, you risk truly confusing your computer and probably causing problems. Therefore, you need to put some thought into these two. You can install two or even three antivirus programs on your computer, but only run one at any time; use the others (turn one off and another on) to run a confirmation scan periodically or when in doubt. Take care to keep any installed programs updated. Firewalls are covered elsewhere. Here, we'll look at antivirus programs.
The absolute best antivirus programs are commercial. They usually come bundled with other security programs and are variously called a "suite," "system" or other such word denoting a comprehensive collection of programs designed to perform multiple, often overlapping functions. There is no doubt that this is by far the best way to go if you can afford the price. You get everything, it all works together without conflict or confusion and frequent (usually daily) updates keep the virus and malware definition files cutting-edge current.
But, as in any market, there are still inferior commercial products. Rather than buy one of these you would be better off downloading a collection of the best free programs out there.
Many of the better commercial products offer "trial" versions that do what the commercial version does but only remains active for a short period, usually 14 or 30 days. We will not cover those here because they offer no free, long-term solution for you. Some companies offer a free version -- usually of a specific program rather than the entire suite -- that only does 85-90% of what the commercial equivalent does. Depending on what that 85-90% contains and how it performs, we may or may not cover it here. Generally, we are looking for a complete vehicle, not one with electric windows that don't work, no rear-view mirror and a flat spare tire.
A final foreword: some of the better free programs are bundled with other security functions to provide a mini-suite. Most often antivirus and anti-malware functions are bundled, but sometimes a password manager and/or identity shield is included. These are things to consider when selecting a product but should not be the sole determinant. Indeed, the primary selection factor should always be how well it does the job.
Avira Free Antivirus
A couple of years ago Avira Free Antivirus pretty much blew away the competition with its exceptional detection rate, user-friendly features and robust help engine. Two versions later and bundled with a very decent anti-spyware program, Avira Free Antivirus still ranks among the top free antivirus programs and detects 99.99% of malware.
But if you were unaware of this long view you would probably be delighted with the product. It still ranks at or near the top for effective virus detection, blockage and removal. Its updated heuristic engine offers three protection levels and can be partially or wholly turned off. It can open locked files and defends itself against modification or shutdown by malware.
The program's interface, once considered cutting-edge, has changed little. Users are still offered more configuration and action choices than most programs offer. Quarantined files, for example, are displayed in detail and you can scan them collectively or individually again, restore them, delete them, do nothing, or email them to Avira for confirmation. Scans can be configured in many ways, and both scans and updates can be scheduled variously.
Systems: Windows and UNIX
avast! Free Antivirus
Avast! Free Antivirus is packaged with a suite of security programs -- antivirus, antispyware, heuristics analysis, a file system / mail shield, a web shield, a network shield, IM and P2P shielding, and a script shield. On top of that, the antivirus functionality is possibly the most complete and effective available.
The antispyware features are examined on our antispyware page, so all we shall say here is that this is a most worthy program for your consideration. What it lacks in completeness -- antispam, firewall and testing sandbox -- can be picked up elsewhere, making avast! Free Antivirus an 80% solution to your computer security needs.
But it is in the antivirus area that we focus upon here, and as we said before it is possibly the most effective and complete free antivirus solution out there. With over 90 million downloads from CNET alone, it is second in user popularity. According to independent testing laboratories, avast! Free Antivirus is one of the best, if not the best, free antivirus solutions available.
An antivirus program, no matter how effective, offers false security if not updated regularly. Avast delivers virus signature updates automatically on a daily basis, but they can be sought manually if your logon times do not match your scheduled update times. But when Avast issues a new update for new, “zero-hour” malware, they immediately push the update to you.
Systems: Windows 2000, XP, Vista and 7
AVG Anti-Virus Free Edition
Over 290 million users (and growing) trust their computers to AVG Anti-Virus Free Edition. For all that popularity, it essentially remains just an antivirus program. If you want any other computer security features -- anti-phishing, anti-spam, firewall, anti-rootkit, real time online, speedier gaming mode, identity guard, technical support -- you must obtain these elsewhere. Basically, what you get is a good antivirus program, email scanning, basic antispyware protection, and LinkScanner. As one reviewer said, "AVG Free provides the bare necessities when it comes to security, but that should be enough for savvy Windows users." We agree. You will have to decide if you are "savvy" or not.
Like most programs, it offers three scan speeds. Speed means degrees of thoroughness. The slower the scan, the more comprehensive it is. We recommend you set the first scan to slow and go do something else. After that, you can set it to automatic or fast, the latter being the least comprehensive but then your system should already be clean.
Any good antivirus program should offer you a way out should a virus cause serious problems. AVG does just that, creating a rescue disk to scan your system in DOS mode. AVG also offers free downloads of 37 different virus removal tools for really nasty critters.
Systems: Windows 2000, XP, Vista, 7, and a LINUX version
Clam AntiVirus is an open source anti-virus toolkit for UNIX, adapted for Windows and other operating systems, designed especially for e-mail scanning on mail gateways. It provides a number of utilities including a flexible and scalable multi-threaded daemon, a command line scanner, and an advanced tool for automatic database updates. The core of the package is an anti-virus engine available in the form of a shared library.
The main features include a fast, multi-threaded daemon with support for on-access scanning, milter interface for sendmail, advanced database updater with support for scripted updates and digital signatures, virus scanner C library, on-access scanning (Linux and FreeBSD), virus database updated multiple times per day, built-in support for various archive formats, including Zip, RAR, Tar, Gzip, Bzip2, OLE2, Cabinet, CHM, BinHex, SIS and others, built-in support for almost all mail file formats, built-in support for ELF executables and Portable Executable files compressed with UPX, FSG, Petite, NsPack, wwpack32, MEW, Upack and obfuscated with SUE, Y0da Cryptor and others, and built-in support for popular document formats including MS Office and MacOffice files, HTML, RTF and PDF.
Two open-source Windows versions are also available (32-bit and 64-bit).
Systems: Linux distributions (Debian, RedHat, Fedora, PLD Linux, Mandrake), FreeBSD, OpenBSD, AIX, OSF, Solaris 8 (Sparc), and Microsoft Windows (32-bit and 64-bit builds)
Comodo Internet Security
Comodo's free antivirus program is now packaged with their firewall program and renamed Comodo Internet Security. A commercial version is called Internet Security Pro, but the basic package is still free. Download it and then choose to install the firewall as a stand-alone, the anti-virus as a stand-alone or both together.
The antivirus program detects, blocks and eliminates all known viruses, trojans and worms from desktops and networks and constantly protects with real-time On Access scanning. A built-in scheduler allows you to run scans at a time that suits you, and it automatically checks for and uploads virus definition updates. Essentially, it is "install and forget" background protection.
The latest version (4.0) contains a proactive defensive sandbox which combines file system/registry virtualization and least-privileged user account principle in order to combat with unknown malware. The program automatically sandboxes all unknown applications and executables until they are analyzed.
The firewall blocks both incoming and outgoing traffic not directed by you. But Comodo also watches for suspicious activity and blocks programs that behave suspiciously.
Comodo Internet Security allows three settings -- Firewall Only, Firewall Security (the default setting) and Proactive Security. The latter is the most secure. In any of the settings, the program will run in "Clean PC Mode" or "Safe Mode." Clean PC Mode assumes everything already on your computer (even malware, if there) as safe. While convenient, it is not the wisest choice. Safe Mode is the best choice, although it will initially require you to "allow" and "remember" each program you trust to connect to the outside world. After that, it only asks you to allow incoming packets.
This is, by far, the best of the free firewalls if run correctly. It does insist that you approve each program at first, but after a while it will have learned what to trust.
Systems: 32-bit Windows XP and both 32- and 64-bit Vista and 7
Immunet Protect Free Antivirus
Immunet Protect Free Antivirus is a fast, companion antivirus program based on the Clam AV engine and designed to offer an extra layer of protection compatible with your existing antivirus software. It has a small disk and low memory footprint, won't slow down your PC, with real-time, Cloud-based detection (no virus update downloads are required). For offline scanning, advanced virus removal, and email support you have to upgrade to the commercial product or run this program as intended with another AV program.
Systems: Microsoft IE 7 or later, Windows XP, Vista, 7
Panda Cloud Antivirus Free Edition
The obvious question from the novice when he sees the name Panda Cloud Antivirus Free Edition is what is "cloud" antivirus? It has no obvious, intuitive meaning. So before we get to the software, let's tackle the term.
Computing "in the cloud" means so many things (because so many vendors have latched on to the term and applied it somehow to their own products) that it actually has no concrete meaning. As used by Panda Cloud Antivirus (PCAV), it means the virus and malware signature files are located on Panda Security's server, not your local PC. When your program is scanning, it downloads the antivirus signature file and a programmatic white list into local memory for fast scanning and action. When it encounters an executable it doesn't recognize, it pulls, encrypts and sends essential data on the file to its data center "in the cloud" where it gets a quick determination as to whether it is a know good or bad program, or an unknown. If unknown, your local program then sends additional information upward where heuristic analysis is performed. It may also send the file's internal structure up for similarity analysis. While this all takes time, it is extremely fast. On dual- and quad-core processors, the program continues its scan while these functions are occurring. If the file is identified as good, the executable's name is locally and remotely listed for ultrafast recognition later. If determined to be bad or unknown, its access is blocked and it is placed in the program's recycle bin for your later action.
PCAV Free Edition offers both antivirus and antispyware protection "from the cloud." Permanent protection is both online and offline. It seeks out, destroys and blocks rootkits. Other features include incorporating behavioral blocking (Panda Security pioneered this technology in 2004), disabling Autorun.ini and advanced configuration and exclusion settings.
The program's download file is small and installs extremely fast. Because it doesn't have to download and then update a signature (virus definition) file, it is up and running long before almost every other antivirus program completes its install routine. It then immediately goes to work. The user interface is simple, easy to grasp and uncluttered.
When PCAV discovers a suspicious file it cannot yet identify, or finds "potentiall unwanted programs," it neither deletes nor renames them, but rather blocks access to them and puts them in a recycle bin. There, you can delete or restore them.
Although the program does perform an impressive amount of anti-malware duty, it is notably weak against rootkits. This will probably change soon.
Systems: Windows NT, XP, 7
PC Tools AntiVirus Free Edition
PC Tools AntiVirus Free Edition does everything a solid antivirus program is expected to do. It protects your PC as you are working, surfing online, corresponding via email, and just playing. It detects, quarantines, disinfects and destroys traditional viruses, trojans and worms. It protects your computer against threats in real-time, checking all inbound and outbound transmissions. It runs on demand or scheduled scans, and it automatically checks for frequent updates against the latest threats.
Systems: Windows XP, Vista and 7
ThreatFire Antivirus Free Edition
Computers are faced with emerging threats on a continuous basis. Signature based scanners can only detect what has already be found, analyzed and signature-defined. PC Tools ThreatFire is one of those programs that provides behavior-based protection to guard against new, unknown forms of malware traditional scanners might miss.
ThreatFire (formerly CyberHawk, before buyout by PC Tools) runs in the background, monitoring each program's activities. It quarantines known malware and alerts you about activities it considers suspicious. Its user interface is both intuitive and well designed, making it easy to use. It is pre-configured for optimum effectiveness, but you can tweak it to your heart's desire.
ThreatFire is ideally suited to supplement antivirus and other security software to provide a layer of protection in an area often sparsely covered at best.
Systems: Windows 2000, 2003 Server, XP, Vista
VIPRE Rescue Program
The VIPRE Rescue Program is a command-line utility that will scan and clean an infected computer that is so infected that programs cannot be easily run. It is not intended to replace your normal antivirus program that runs in the background and protects your machine day-to-day. However, if your computer needs the VIPRE Rescue Program, I would seriously consider replacing your normal antivirus program.
The VIPRE Rescue Program is packaged into a self-extracting executable file (.exe) that prompts the user for an "unpack" or installation location, then starts the scanner and performs a deep scan. The user can start the program either by opening it via Windows or from the command line.
Virus definitions are included, and the program is self-running once executed. The initial scan, and all subsequent scans, include Rootkit Detection. Four command line options are available, perform a deep scan, perform a quick scan, log the events, and disabling the rootkit.
Detections are consistent with the full VIPRE ensemble, and the VIPRE Rescue Program is designed to disinfect a system so infected that a user cannot install it normally.
Systems: Windows 2000, XP, Vista, 7