Other methods to the Anti-virus

A command-line virus scanner, Clam AV 0.95.2, running a virus signature definition update, scanning a file and identifying a Trojan

Installed antivirus software running on an individual computer is only one method of guarding against viruses. Other methods are also used, including cloud-based antivirus, firewalls and on-line scanners.

Cloud antivirus

Cloud antivirus is a technology that uses lightweight agent software on the protected computer, while offloading the majority of data analysis to the provider's infrastructure.^[56]
One approach to implementing cloud antivirus involves scanning suspicious files using multiple antivirus engines. This approach was proposed by an early implementation of the cloud antivirus concept called CloudAV. CloudAV was designed to send programs or documents to a network cloud where multiple antivirus and behavioral detection programs are used simultaneously in order to improve detection rates. Parallel scanning of files using potentially incompatible antivirus scanners is achieved by spawning a virtual machine per detection engine and therefore eliminating any possible issues. CloudAV can also perform "retrospective detection," whereby the cloud detection engine rescans all files in its file access history when a new threat is identified thus improving new threat detection speed. Finally, CloudAV is a solution for effective virus scanning on devices that lack the computing power to perform the scans themselves.^[57]

[edit] Network firewall

Network firewalls prevent unknown programs and processes from accessing the system. However, they are not antivirus systems and make no attempt to identify or remove anything. They may protect against infection from outside the protected computer or network, and limit the activity of any malicious software which is present by blocking incoming or outgoing requests on certain TCP/IP ports. A firewall is designed to deal with broader system threats that come from network connections into the system and is not an alternative to a virus protection system.

Online scanning

Some antivirus vendors maintain websites with free online scanning capability of the entire computer, critical areas only, local disks, folders or files. Periodic online scanning is a good idea for those that run antivirus applications on their computers because those applications are frequently slow to catch threats. One of the first things that malicious software does in an attack is disable any existing antivirus software and sometimes the only way to know of an attack is by turning to an online resource that isn't already installed on the infected computer.^[58]

Specialist tools

Using rkhunter to scan for rootkits on an Ubuntu Linux computer.

Virus removal tools are available to help remove stubborn infections or certain types of infection. Examples include Trend Micro's Rootkit Buster,^[59] and rkhunter for the detection of rootkits, Avira's AntiVir Removal Tool,^[60] PCTools Threat Removal Tool,^[61] and AVG's Anti-Virus Free 2011.^[62]
A rescue disk that is bootable, such as a CD or USB storage device, can be used to run antivirus software outside of the installed operating system, in order to remove infections while they are dormant. A bootable antivirus disk can be useful when, for example, the installed operating system is no longer bootable or has malware that is resisting all attempts to be removed by the installed antivirus software. Examples of some of these bootable disks include the Avira AntiVir Rescue System,^[60] PCTools Alternate Operating System Scanner,^[63] and AVG Rescue CD.^[64] The AVG Rescue CD software can also be installed onto a USB storage device, that is bootable on newer computers.^[64]

Popularity

According to an FBI survey, major businesses lose $12 million annually dealing with virus incidents.^[65] A survey by Symantec in 2009 found that a third of small to medium sized business did not use antivirus protection at that time, whereas more than 80% of home users had some kind of antivirus installed.