Malware Remedies and Prevention

A number of techniques have emerged to counteract the threat of malware. These include programs to remove or to block spyware, as well as user practices that reduce the chance of spyware infecting your system.

Nevertheless, when a large number of pieces of spyware have infected a Windows computer, the only remedy may involve backing up user data, and fully reinstalling the operating system.

Anti-spyware programs

Many programmers and some commercial firms have released products designed to remove or block spyware. Programs such as Lavasoft's Ad-Aware SE (free scans for non-commercial users, must pay for other features) and Patrick Kolla's Spybot - Search & Destroy (all features free for non-commercial use) gained popularity as effective tools to remove, or intercept, spyware programs. More recently Microsoft acquired GIANT AntiSpyware software, rebranding it as Windows AntiSpyware beta and releasing it as a free download for Genuine Windows XP and Windows 2003 users. In 2006, Microsoft renamed the beta software to Windows Defender (free), and it was released as a free download in October 2006 and is included as standard with Windows Vista. Other well-known commercial anti-spyware products include:

IS3's STOPzilla (free scan and purchase to activate)
PC Tools's Spyware Doctor (free scans but you have to pay to remove the spyware)
Sunbelt Software's Counterspy (15-day free trial)
Trend Micro's HijackThis (free)
Webroot Software's Spy Sweeper (free version does not remove spyware)
ParetoLogic's Anti-Spyware and XoftSpy SE (free version does not remove spyware)

Major anti-virus firms such as Symantec, McAfee and Sophos have come later to the table, adding anti-spyware features to their existing anti-virus products. Early on, anti-virus firms expressed reluctance to add anti-spyware functions, citing lawsuits brought by spyware authors against the authors of web sites and programs which described their products as "spyware". However, recent versions of these major firms' home and business anti-virus products do include anti-spyware functions, albeit treated differently from viruses. Symantec Anti-Virus, for instance, categorizes spyware programs as "extended threats" and now offers real-time protection from them (as it does for viruses).

Recently, the anti-virus company Grisoft, creator of AVG Anti-Virus, acquired anti-spyware firm Ewido Networks, re-labeling their Ewido anti-spyware program as AVG Anti-Spyware Professional Edition. AVG also used this product to add an integrated anti-spyware solution to some versions of the AVG Anti-Virus family of products, plus made a freeware AVG Anti-Spyware Free Edition available for private and non-commercial use. This shows a trend by anti virus companies to launch a dedicated solution to spyware and malware. Zone Labs, creator of Zone Alarm firewall have also released an anti-spyware program.

Anti-spyware programs can combat spyware in two ways:

They can provide real time protection against the installation of spyware software on your computer. This type of spyware protection works the same way as that of anti-virus protection in that the anti-spyware software scans all incoming network data for spyware software and blocks any threats it comes across.
Anti-spyware software programs can be used solely for detection and removal of spyware software that has already been installed onto your computer. This type of spyware protection is normally much easier to use and more popular. With this spyware protection software you can schedule weekly, daily, or monthly scans of your computer to detect and remove any spyware software that has been installed on your computer. This type of anti-spyware software scans the contents of the windows registry, operating system files, and installed programs on your computer and will provide a list of any threats found, allowing you to choose what you want to delete and what you want to keep.

Such programs inspect the contents of the Windows registry, the operating system files, and installed programs, and remove files and entries which match a list of known spyware components. Real-time protection from spyware works identically to real-time anti-virus protection: the software scans disk files at download time, and blocks the activity of components known to represent spyware. In some cases, it may also intercept attempts to install start-up items or to modify browser settings. Because many spyware and adware are installed as a result of browser exploits or user error, using security software (some of which are antispyware, though many are not) to sandbox browsers can also be effective to help restrict any damage done.

Earlier versions of anti-spyware programs focused chiefly on detection and removal. Javacool Software's SpywareBlaster, one of the first to offer real-time protection, blocked the installation of ActiveX-based and other spyware programs.

Like most anti-virus software, many anti-spyware/adware tools require a frequently-updated database of threats. As new spyware programs are released, anti-spyware developers discover and evaluate them, making "signatures" or "definitions" which allow the software to detect and remove the spyware. As a result, anti-spyware software is of limited usefulness without a regular source of updates. Some vendors provide a subscription-based update service, while others provide updates free. Updates may be installed automatically on a schedule or before doing a scan, or may be done manually.

Not all programs rely on updated definitions. Some programs rely partly (for instance many antispyware programs such as Windows Defender, Spybot's TeaTimer and Spysweeper) or fully (programs falling under the class of Hips such as BillP's WinPatrol) on historical observation. They watch certain configuration parameters (such as certain portions of the Windows registry or browser configuration) and report any change to the user, without judgment or recommendation. While they do not rely on updated definitions, which may allow them to spot newer spyware, they can offer no guidance. The user is left to determine "what did I just do, and is this configuration change appropriate?"

Windows Defender's Spynet attempts to alleviate this through offering a community to share information, which helps guide both users, who can look at decisions made by others, and analysts, who can spot fast-spreading spyware. A popular generic spyware removal tool used by those with a certain degree of expertise is HijackThis, which scans certain areas of the Windows OS where spyware often resides and presents a list with items to delete manually. As most of the items are legitimate windows files/registry entries it is advised for those who are less knowledgeable on this subject to post a HijackThis log on the numerous antispyware sites and let the experts decide what to delete.

If a spyware program is not blocked and manages to get itself installed, it may resist attempts to terminate or uninstall it. Some programs work in pairs: when an anti-spyware scanner (or the user) terminates one running process, the other one respawns the killed program. Likewise, some spyware will detect attempts to remove registry keys and immediately add them again. Usually, booting the infected computer in safe mode allows an anti-spyware program a better chance of removing persistent spyware. Killing the process tree can also work.

A new breed of spyware (Look2Me spyware by NicTechNetworks is a good example) is starting to hide inside system-critical processes and start up even in safe mode. With no process to terminate they are harder to detect and remove. Sometimes they do not even leave any on-disk signatures. Rootkit technology is also seeing increasing use, as is the use of NTFS alternate data streams. Newer spyware programs also have specific countermeasures against well known anti-malware products and may prevent them from running or being installed, or even uninstall them. An example of one that uses all three methods is Gromozon, a new breed of malware. It uses alternate data streams to hide. A rootkit hides it even from alternate data streams scanners and actively stops popular rootkit scanners from running.

Fake anti-spyware programs

Malicious programmers have released a large number of fake anti-spyware programs, and widely distributed Web banner ads now spuriously warn users that their computers have been infected with spyware, directing them to purchase programs which do not actually remove spyware?or worse, may add more spyware of their own.

The recent proliferation of fake or spoofed antivirus products has occasioned some concern. Such products often bill themselves as antispyware, antivirus, or registry cleaners, and sometimes feature popups prompting users to install them. This software is called rogue software.

It recommended that users do not install any free software claiming to be anti-spyware unless it is verified to be legitimate. Some known offenders include:

AntiVirus Gold
ContraVirus
Errorsafe (AKA system doctor)
MacSweeper
PAL Spyware Remover
Pest Trap
PSGuard
SpywareStrike
Spyware Quake
Spydawn
Spylocked
SpyShredder
Spy Sheriff
Spy Wiper
UltimateCleaner
WinAntiVirus Pro 2006
WinFixer
WorldAntiSpy

On January 26, 2006, Microsoft and the Washington state attorney general filed suit against Secure Computer for its Spyware Cleaner product. On December 4, 2006, the Washington attorney general announced that Secure Computer had paid $1 million to settle with the state. As of that date, Microsoft's case against Secure Computer remained pending.

Security practices

To deter spyware, computer users have found several practices useful in addition to installing anti-spyware programs.

Many system operators install a web browser other than IE, such as Opera or Mozilla Firefox.Though no browser is completely safe, Internet Explorer is at a greater risk for spyware infection due to its large user base as well as vulnerabilities such as ActiveX.

Some ISPs, particularly colleges and universities, have taken a different approach to blocking spyware: they use their network firewalls and web proxies to block access to Web sites known to install spyware. On March 31, 2005, Cornell University's Information Technology department released a report detailing the behavior of one particular piece of proxy-based spyware, Marketscore, and the steps the university took to intercept it. Other educational institutions have taken similar steps. Spyware programs which redirect network traffic cause greater technical-support problems than programs which merely display ads or monitor users' behavior, and so may more readily attract institutional attention.

Some users install a large hosts file which prevents the user's computer from connecting to known spyware related web addresses. However, by connecting to the numeric IP address, rather than the domain name, spyware may bypass this sort of protection.

Spyware may get installed via certain shareware programs offered for download. Downloading programs only from reputable sources can provide some protection from this source of attack. Recently, CNet revamped its download directory: it has stated that it will only keep files that pass inspection by Ad-Aware and Spyware Doctor.