Antivirus software was originally developed to detect and remove computer viruses, hence the name. However, with the proliferation of other kinds of malware, antivirus software started to provide protection from other computer threats. In particular, modern antivirus software can protect users from: malicious browser helper objects (BHOs), browser hijackers, ransomware, keyloggers, backdoors, rootkits, trojan horses, worms, malicious LSPs, dialers, fraudtools, adware and spyware. Some products also include protection from other computer threats, such as infected and malicious URLs, spam, scam and phishing attacks, online identity (privacy), online banking attacks, social engineering techniques, advanced persistent threat (APT) and botnet DDoS attacks.
1949–1980 period (pre-antivirus days)Edit
Although the roots of the computer virus date back as early as 1949, when the Hungarian scientist John von Neumann published the "Theory of self-reproducing automata", the first known computer virus appeared in 1971 and was dubbed the "Creeper virus". This computer virus infected Digital Equipment Corporation's (DEC) PDP-10 mainframe computers running the TENEX operating system.
The Creeper virus was eventually deleted by a program created by Ray Tomlinson and known as "The Reaper". Some people consider "The Reaper" the first antivirus software ever written – it may be the case, but it is important to note that the Reaper was actually a virus itself specifically designed to remove the Creeper virus.
In 1983, the term "computer virus" was coined by Fred Cohen in one of the first ever published academic papers on computer viruses. Cohen used the term "computer virus" to describe a program that: "affect other computer programs by modifying them in such a way as to include a (possibly evolved) copy of itself." (note that a more recent, and precise, definition of computer virus has been given by the Hungarian security researcher Péter Szőr: "a code that recursively replicates a possibly evolved copy of itself")
The first IBM PC compatible "in the wild" computer virus, and one of the first real widespread infections, was "Brain" in 1986. From then, the number of viruses has grown exponentially. Most of the computer viruses written in the early and mid-1980s were limited to self-reproduction and had no specific damage routine built into the code. That changed when more and more programmers became acquainted with computer virus programming and created viruses that manipulated or even destroyed data on infected computers.
Before internet connectivity was widespread, computer viruses were typically spread by infected floppy disks. Antivirus software came into use, but was updated relatively infrequently. During this time, virus checkers essentially had to check executable files and the boot sectors of floppy disks and hard disks. However, as internet usage became common, viruses began to spread online.
1980–1990 period (early days)Edit
There are competing claims for the innovator of the first antivirus product. Possibly, the first publicly documented removal of an "in the wild" computer virus (i.e. the "Vienna virus") was performed by Bernd Fix in 1987.
In 1987, Andreas Lüning and Kai Figge, who founded G Data Software in 1985, released their first antivirus product for the Atari ST platform. In 1987, the Ultimate Virus Killer (UVK) was also released. This was the de facto industry standard virus killer for the Atari ST and Atari Falcon, the last version of which (version 9.0) was released in April 2004. In 1987, in the United States, John McAfee founded the McAfee company (was part of Intel Security) and, at the end of that year, he released the first version of VirusScan. Also in 1987 (in Czechoslovakia), Peter Paško, Rudolf Hrubý, and Miroslav Trnka created the first version of NOD antivirus.
In 1987, Fred Cohen wrote that there is no algorithm that can perfectly detect all possible computer viruses.
Finally, at the end of 1987, the first two heuristic antivirus utilities were released: Flushot Plus by Ross Greenberg and Anti4us by Erwin Lanting. In his O'Reilly book, Malicious Mobile Code: Virus Protection for Windows, Roger Grimes described Flushot Plus as "the first holistic program to fight malicious mobile code (MMC)."
However, the kind of heuristic used by early AV engines was totally different from those used today. The first product with a heuristic engine resembling modern ones was F-PROT in 1991. Early heuristic engines were based on dividing the binary in different sections: data section, code section (in a legitimate binary, it usually starts always from the same location). Indeed, the initial viruses re-organized the layout of the sections, or overrode the initial portion of section in order to jump to the very end of the file where malicious code was located—only going back to resume execution of the original code. This was a very specific pattern, not used at the time by any legitimate software, which represented an elegant heuristic to catch suspicious code. Other kinds of more advanced heuristics were later added, such as suspicious section names, incorrect header size, regular expressions, and partial pattern in-memory matching.
In 1988, the growth of antivirus companies continued. In Germany, Tjark Auerbach founded Avira (H+BEDV at the time) and released the first version of AntiVir (named "Luke Filewalker" at the time). In Bulgaria, Dr. Vesselin Bontchev released his first freeware antivirus program (he later joined FRISK Software). Also Frans Veldman released the first version of ThunderByte Antivirus, also known as TBAV (he sold his company to Norman Safeground in 1998). In Czechoslovakia, Pavel Baudiš and Eduard Kučera started avast! (at the time ALWIL Software) and released their first version of avast! antivirus. In June 1988, in South Korea, Dr. Ahn Cheol-Soo released its first antivirus software, called V1 (he founded AhnLab later in 1995). Finally, in the Autumn 1988, in United Kingdom, Alan Solomon founded S&S International and created his Dr. Solomon's Anti-Virus Toolkit (although he launched it commercially only in 1991 – in 1998 Dr. Solomon’s company was acquired by McAfee). In November 1988 a professor at the Panamerican University in Mexico City named Alejandro E. Carriles copyrighted the first antivirus software in Mexico under the name "Byte Matabichos" (Byte Bugkiller) to help solve the rampant virus infestation among students.
Also in 1988, a mailing list named VIRUS-L was started on the BITNET/EARN network where new viruses and the possibilities of detecting and eliminating viruses were discussed. Some members of this mailing list were: Alan Solomon, Eugene Kaspersky (Kaspersky Lab), Friðrik Skúlason (FRISK Software), John McAfee (McAfee), Luis Corrons (Panda Security), Mikko Hyppönen (F-Secure), Péter Szőr, Tjark Auerbach (Avira) and Dr. Vesselin Bontchev (FRISK Software).
In 1989, in Iceland, Friðrik Skúlason created the first version of F-PROT Anti-Virus back in 1989 (he founded FRISK Software only in 1993). In the meanwhile, in United States, Symantec (founded by Gary Hendrix in 1982) launched its first Symantec antivirus for Macintosh (SAM). SAM 2.0, released March 1990, incorporated technology allowing users to easily update SAM to intercept and eliminate new viruses, including many that didn't exist at the time of the program's release.
In the end of the 1980s, in United Kingdom, Jan Hruska and Peter Lammer founded the security firm Sophos and began producing their first antivirus and encryption products. In the same period, in Hungary, also VirusBuster was founded (which has recently being incorporated by Sophos).
1990–2000 period (emergence of the antivirus industry)Edit
In 1990, in Spain, Mikel Urizarbarrena founded Panda Security (Panda Software at the time). In Hungary, the security researcher Péter Szőr released the first version of Pasteur antivirus. In Italy, Gianfranco Tonello created the first version of VirIT eXplorer antivirus (he founded TG Soft one year later).
In 1990, the Computer Antivirus Research Organization (CARO) was founded. In 1991, CARO released the "Virus Naming Scheme", originally written by Friðrik Skúlason and Vesselin Bontchev. Although this naming scheme is now outdated, it remains the only existing standard that most computer security companies and researchers ever attempted to adopt. CARO members includes: Alan Solomon, Costin Raiu, Dmitry Gryaznov, Eugene Kaspersky, Friðrik Skúlason, Igor Muttik, Mikko Hyppönen, Morton Swimmer, Nick FitzGerald, Padgett Peterson, Peter Ferrie, Righard Zwienenberg and Dr. Vesselin Bontchev.
In 1991, in the United States, Symantec released the first version of Norton AntiVirus. In the same year, in the Czech Republic, Jan Gritzbach and Tomáš Hofer founded AVG Technologies (Grisoft at the time), although they released the first version of their Anti-Virus Guard (AVG) only in 1992. On the other hand, in Finland, F-Secure (founded in 1988 by Petri Allas and Risto Siilasmaa – with the name of Data Fellows) released the first version of their antivirus product. F-Secure claims to be the first antivirus firm to establish a presence on the World Wide Web.
In 1991, the European Institute for Computer Antivirus Research (EICAR) was founded to further antivirus research and improve development of antivirus software.
Over time other companies were founded. In 1996, in Romania, Bitdefender was founded and released the first version of Anti-Virus eXpert (AVX). In 1997, in Russia, Eugene Kaspersky and Natalya Kaspersky co-founded security firm Kaspersky Lab.
In 2000, Rainer Link and Howard Fuhs started the first open source antivirus engine, called OpenAntivirus Project.
In 2001, Tomasz Kojm released the first version of ClamAV, the first ever open source antivirus engine to be commercialised. In 2007, ClamAV was bought by Sourcefire, which in turn was acquired by Cisco Systems in 2013.
In 2007, AV-TEST reported a number of 5,490,960 new unique malware samples (based on MD5) only for that year. In 2012 and 2013, antivirus firms reported a new malware samples range from 300,000 to over 500,000 per day.
Over the years it has become necessary for antivirus software to use several different strategies (e.g. specific email and network protection or low level modules) and detection algorithms, as well as to check an increasing variety of files, rather than just executables, for several reasons:
- Powerful macros used in word processor applications, such as Microsoft Word, presented a risk. Virus writers could use the macros to write viruses embedded within documents. This meant that computers could now also be at risk from infection by opening documents with hidden attached macros.
- The possibility of embedding executable objects inside otherwise non-executable file formats can make opening those files a risk.
- Later email programs, in particular Microsoft's Outlook Express and Outlook, were vulnerable to viruses embedded in the email body itself. A user's computer could be infected by just opening or previewing a message.
In 2005, F-Secure was the first security firm that developed an Anti-Rootkit technology, called BlackLight.
In February 2008 McAfee Labs added the industry-first cloud-based anti-malware functionality to VirusScan under Artemis name. It was tested by AV-Comparatives in February 2008 and officially unveiled in August 2008 in McAfee VirusScan.
Cloud AV created problems for comparative testing of security software – part of the AV definitions was out of testers control (on constantly updated AV company servers) thus making results non-repeatable. As a result, Anti-Malware Testing Standards Organisation (AMTSO) started working on methodology of testing cloud products which was adopted on May 7, 2009.
2014–present (rise of next-gen)Edit
Following the 2014 release of the APT 1 report from Mandiant, the industry has seen a shift towards signature-less approaches to the problem capable of detecting and mitigating zero-day attacks. Numerous approaches to address these new forms of threats have appeared, including behavioral detection, artificial intelligence, machine learning, and cloud-based file detonation. According to Gartner, it is expected the rise of new entrants, such Carbon Black, Cylance and Crowdstrike will force EPP incumbents into a new phase of innovation and acquisition. One method from Bromium involves micro-virtualization to protect desktops from malicious code execution initiated by the end user. Another approach from SentinelOne and Carbon Black focuses on behavioral detection by building a full context around every process execution path in real time, while Cylance leverages an artificial intelligence model based on machine learning. Increasingly, these signature-less approaches have been defined by the media and analyst firms as "next-generation" antivirus and are seeing rapid market adoption as certified antivirus replacement technologies by firms such as Coalfire and DirectDefense. In response, traditional antivirus vendors such as Trend Micro, Symantec and Sophos have responded by incorporating "next-gen" offerings into their portfolios as analyst firms such as Forrester and Gartner have called traditional signature-based antivirus "ineffective" and "outdated".
One of the few solid theoretical results in the study of computer viruses is Frederick B. Cohen's 1987 demonstration that there is no algorithm that can perfectly detect all possible viruses. However, using different layers of defense, a good detection rate may be achieved.
There are several methods which antivirus engine can use to identify malware:
- Sandbox detection: a particular behavioural-based detection technique that, instead of detecting the behavioural fingerprint at run time, it executes the programs in a virtual environment, logging what actions the program performs. Depending on the actions logged, the antivirus engine can determine if the program is malicious or not. If not, then, the program is executed in the real environment. Albeit this technique has shown to be quite effective, given its heaviness and slowness, it is rarely used in end-user antivirus solutions.
- Data mining techniques: one of the latest approach applied in malware detection. Data mining and machine learning algorithms are used to try to classify the behaviour of a file (as either malicious or benign) given a series of file features, that are extracted from the file itself.
Traditional antivirus software relies heavily upon signatures to identify malware.
Substantially, when a malware arrives in the hands of an antivirus firm, it is analysed by malware researchers or by dynamic analysis systems. Then, once it is determined to be a malware, a proper signature of the file is extracted and added to the signatures database of the antivirus software.
Although the signature-based approach can effectively contain malware outbreaks, malware authors have tried to stay a step ahead of such software by writing "oligomorphic", "polymorphic" and, more recently, "metamorphic" viruses, which encrypt parts of themselves or otherwise modify themselves as a method of disguise, so as to not match virus signatures in the dictionary.
Many viruses start as a single infection and through either mutation or refinements by other attackers, can grow into dozens of slightly different strains, called variants. Generic detection refers to the detection and removal of multiple threats using a single virus definition.
For example, the Vundo trojan has several family members, depending on the antivirus vendor's classification. Symantec classifies members of the Vundo family into two distinct categories, Trojan.Vundo and Trojan.Vundo.B.
While it may be advantageous to identify a specific virus, it can be quicker to detect a virus family through a generic signature or through an inexact match to an existing signature. Virus researchers find common areas that all viruses in a family share uniquely and can thus create a single generic signature. These signatures often contain non-contiguous code, using wildcard characters where differences lie. These wildcards allow the scanner to detect viruses even if they are padded with extra, meaningless code. A detection that uses this method is said to be "heuristic detection."
Anti-virus software can attempt to scan for rootkits. A rootkit is a type of malware designed to gain administrative-level control over a computer system without being detected. Rootkits can change how the operating system functions and in some cases can tamper with the anti-virus program and render it ineffective. Rootkits are also difficult to remove, in some cases requiring a complete re-installation of the operating system.
Real-time protection, on-access scanning, background guard, resident shield, autoprotect, and other synonyms refer to the automatic protection provided by most antivirus, anti-spyware, and other anti-malware programs. This monitors computer systems for suspicious activity such as computer viruses, spyware, adware, and other malicious objects in 'real-time', in other words while data loaded into the computer's active memory: when inserting a CD, opening an email, or browsing the web, or when a file already on the computer is opened or executed.
Issues of concernEdit
Unexpected renewal costsEdit
Some commercial antivirus software end-user license agreements include a clause that the subscription will be automatically renewed, and the purchaser's credit card automatically billed, at the renewal time without explicit approval. For example, McAfee requires users to unsubscribe at least 60 days before the expiration of the present subscription while BitDefender sends notifications to unsubscribe 30 days before the renewal. Norton AntiVirus also renews subscriptions automatically by default.
Rogue security applicationsEdit
Problems caused by false positives,Edit
A "false positive" or "false alarm" is when antivirus software identifies a non-malicious file as malware. When this happens, it can cause serious problems. For example, if an antivirus program is configured to immediately delete or quarantine infected files, as is common on Microsoft Windows antivirus applications, a false positive in an essential file can render the Windows operating system or some applications unusable. Recovering from such damage to critical software infrastructure incurs technical support costs and businesses can be forced to close whilst remedial action is undertaken. For example, in May 2007 a faulty virus signature issued by Symantec mistakenly removed essential operating system files, leaving thousands of PCs unable to boot.
Also in May 2007, the executable file required by Pegasus Mail on Windows was falsely detected by Norton AntiVirus as being a Trojan and it was automatically removed, preventing Pegasus Mail from running. Norton AntiVirus had falsely identified three releases of Pegasus Mail as malware, and would delete the Pegasus Mail installer file when that happened. In response to this Pegasus Mail stated:
|“||On the basis that Norton/Symantec has done this for every one of the last three releases of Pegasus Mail, we can only condemn this product as too flawed to use, and recommend in the strongest terms that our users cease using it in favour of alternative, less buggy anti-virus packages.||”|
In April 2010, McAfee VirusScan detected svchost.exe, a normal Windows binary, as a virus on machines running Windows XP with Service Pack 3, causing a reboot loop and loss of all network access.
In September 2012, Sophos' anti-virus suite identified various update-mechanisms, including its own, as malware. If it was configured to automatically delete detected files, Sophos Antivirus could render itself unable to update, required manual intervention to fix the problem.
Running (the real-time protection of) multiple antivirus programs concurrently can degrade performance and create conflicts. However, using a concept called multiscanning, several companies (including G Data Software and Microsoft) have created applications which can run multiple engines concurrently.
It is sometimes necessary to temporarily disable virus protection when installing major updates such as Windows Service Packs or updating graphics card drivers. Active antivirus protection may partially or completely prevent the installation of a major update. Anti-virus software can cause problems during the installation of an operating system upgrade, e.g. when upgrading to a newer version of Windows "in place" — without erasing the previous version of Windows. Microsoft recommends that anti-virus software be disabled to avoid conflicts with the upgrade installation process. Active anti-virus software can also interfere with a firmware update process.
The functionality of a few computer programs can be hampered by active anti-virus software. For example, TrueCrypt, a disk encryption program, states on its troubleshooting page that anti-virus programs can conflict with TrueCrypt and cause it to malfunction or operate very slowly. Anti-virus software can impair the performance and stability of games running in the Steam platform.
Support issues also exist around antivirus application interoperability with common solutions like SSL VPN remote access and network access control products. These technology solutions often have policy assessment applications that require an up-to-date antivirus to be installed and running. If the antivirus application is not recognized by the policy assessment, whether because the antivirus application has been updated or because it is not part of the policy assessment library, the user will be unable to connect.
Studies in December 2007 showed that the effectiveness of antivirus software had decreased in the previous year, particularly against unknown or zero day attacks. The computer magazine c't found that detection rates for these threats had dropped from 40–50% in 2006 to 20–30% in 2007. At that time, the only exception was the NOD32 antivirus, which managed a detection rate of 68%. According to the ZeuS tracker website the average detection rate for all variants of the well-known ZeuS trojan is as low as 40%.
The problem is magnified by the changing intent of virus authors. Some years ago it was obvious when a virus infection was present. The viruses of the day, written by amateurs, exhibited destructive behavior or pop-ups. Modern viruses are often written by professionals, financed by criminal organizations.
Independent testing on all the major virus scanners consistently shows that none provide 100% virus detection. The best ones provided as high as 99.9% detection for simulated real-world situations, while the lowest provided 91.1% in tests conducted in August 2013. Many virus scanners produce false positive results as well, identifying benign files as malware.
Although methodologies may differ, some notable independent quality testing agencies include AV-Comparatives, ICSA Labs, West Coast Labs, Virus Bulletin, AV-TEST and other members of the Anti-Malware Testing Standards Organization.
Anti-virus programs are not always effective against new viruses, even those that use non-signature-based methods that should detect new viruses. The reason for this is that the virus designers test their new viruses on the major anti-virus applications to make sure that they are not detected before releasing them into the wild.
|“||It's something that they miss a lot of the time because this type of [ransomware virus] comes from sites that use a polymorphism, which means they basically randomize the file they send you and it gets by well-known antivirus products very easily. I've seen people firsthand getting infected, having all the pop-ups and yet they have antivirus software running and it's not detecting anything. It actually can be pretty hard to get rid of, as well, and you're never really sure if it's really gone. When we see something like that usually we advise to reinstall the operating system or reinstall backups.||”|
A proof of concept virus has used the Graphics Processing Unit (GPU) to avoid detection from anti-virus software. The potential success of this involves bypassing the CPU in order to make it much harder for security researchers to analyse the inner workings of such malware.
Detecting rootkits is a major challenge for anti-virus programs. Rootkits have full administrative access to the computer and are invisible to users and hidden from the list of running processes in the task manager. Rootkits can modify the inner workings of the operating system and tamper with antivirus programs.
If a file has been infected by a computer virus, anti-virus software will attempt to remove the virus code from the file during disinfection, but it is not always able to restore the file to its undamaged state. In such circumstances, damaged files can only be restored from existing backups or shadow copies (this is also true for ransomware); installed software that is damaged requires re-installation (however, see System File Checker).
Any writeable firmware in the computer can be infected by malicious code. This is a major concern, as an infected BIOS could require the actual BIOS chip to be replaced to ensure the malicious code is completely removed. Anti-virus software is not effective at protecting firmware and the motherboard BIOS from infection. In 2014, security researchers discovered that USB devices contain writeable firmware which can be modified with malicious code (dubbed "BadUSB"), which anti-virus software cannot detect or prevent. The malicious code can run undetected on the computer and could even infect the operating system prior to it booting up.
Performance and other drawbacksEdit
Furthermore, inexperienced users can be lulled into a false sense of security when using the computer, considering themselves to be invulnerable, and may have problems understanding the prompts and decisions that antivirus software presents them with. An incorrect decision may lead to a security breach. If the antivirus software employs heuristic detection, it must be fine-tuned to minimize misidentifying harmless software as malicious (false positive).
Antivirus software itself usually runs at the highly trusted kernel level of the operating system to allow it access to all the potential malicious process and files, creating a potential avenue of attack. The US National Security Agency (NSA) and the UK Government Communications Headquarters (GCHQ) intelligence agencies, respectively, have been exploiting anti-virus software to spy on users. Anti-virus software has highly privileged and trusted access to the underlying operating system, which makes it a much more appealing target for remote attacks. Additionally anti-virus software is "years behind security-conscious client-side applications like browsers or document readers", according to Joxean Koret, a researcher with Coseinc, a Singapore-based information security consultancy.
Antivirus software running on individual computers is the most common method employed of guarding against malware, but it is not the only solution. Other solutions can also be employed by users, including Unified Threat Management (UTM), hardware and network firewalls, Cloud-based antivirus and online scanners.
Hardware and network firewallEdit
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.
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.
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.
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 is not installed on the infected computer.
Virus removal tools are available to help remove stubborn infections or certain types of infection. Examples include Avast Free Anti- Malware, AVG Free Malware Removal Tools, and Avira AntiVir Removal Tool. It is also worth noting that sometimes antivirus software can produce a false positive result, indicating an infection where there is none.
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 Bitdefender Rescue CD, Kaspersky Rescue Disk 2018, and Windows Defender Offline (integrated into Windows 10 since the Anniversary Update). Most of the Rescue CD software can also be installed onto a USB storage device, that is bootable on newer computers.
Usage and risksEdit
According to an FBI survey, major businesses lose $12 million annually dealing with virus incidents. 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. According to a sociological survey conducted by G Data Software in 2010 49% of women did not use any antivirus program at all.
- Anti-virus and anti-malware software
- CARO, the Computer Antivirus Research Organization
- Comparison of antivirus software
- Comparison of computer viruses
- EICAR, the European Institute for Computer Antivirus Research
- Firewall software
- Internet security
- Linux malware
- Quarantine (computing)
- Sandbox (computer security)
- Timeline of computer viruses and worms
- Virus hoax
- Henry, Alan. "The Difference Between Antivirus and Anti-Malware (and Which to Use)". Archived from the original on November 22, 2013.
- "What is antivirus software?". Microsoft. Archived from the original on April 11, 2011.
- von Neumann, John (1966) Theory of self-reproducing automata Archived June 13, 2010, at the Wayback Machine. University of Illinois Press.
- Thomas Chen, Jean-Marc Robert (2004). "The Evolution of Viruses and Worms". Archived from the original on May 17, 2009. Retrieved February 16, 2009.
- From the first email to the first YouTube video: a definitive internet history Archived December 31, 2016, at the Wayback Machine. Tom Meltzer and Sarah Phillips. The Guardian. October 23, 2009
- IEEE Annals of the History of Computing, Volumes 27–28. IEEE Computer Society, 2005. 74 Archived May 13, 2016, at the Wayback Machine: "[...]from one machine to another led to experimentation with the Creeper program, which became the world's first computer worm: a computation that used the network to recreate itself on another node, and spread from node to node."
- John Metcalf (2014). "Core War: Creeper & Reaper". Archived from the original on May 2, 2014. Retrieved May 1, 2014.
- "Creeper – The Virus Encyclopedia". Archived from the original on September 20, 2015.
- "Elk Cloner". Archived from the original on January 7, 2011. Retrieved December 10, 2010.
- "Top 10 Computer Viruses: No. 10 – Elk Cloner". Archived from the original on February 7, 2011. Retrieved December 10, 2010.
- "List of Computer Viruses Developed in 1980s". Archived from the original on July 24, 2011. Retrieved December 10, 2010.
- Fred Cohen: "Computer Viruses – Theory and Experiments" (1983) Archived June 8, 2011, at the Wayback Machine. Eecs.umich.edu (November 3, 1983). Retrieved on 2017-01-03.
- Cohen, Fred (April 1, 1988). "Invited Paper: On the Implications of Computer Viruses and Methods of Defense". Computers & Security. 7 (2): 167–184. doi:10.1016/0167-4048(88)90334-3.
- Szor, Peter (February 13, 2005). The Art of Computer Virus Research and Defense. Addison-Wesley Professional. ISBN 978-0321304544 – via Amazon.
- "Virus Bulletin :: In memoriam: Péter Ször 1970–2013". Archived from the original on August 26, 2014.
- "History of Viruses". October 1992. Archived from the original on April 23, 2011.
- Leyden, John (January 19, 2006). "PC virus celebrates 20th birthday". The Register. Archived from the original on September 6, 2010. Retrieved March 21, 2011.
- Panda Security (April 2004). "(II) Evolution of computer viruses". Archived from the original on August 2, 2009. Retrieved June 20, 2009.
- Kaspersky Lab Virus list. viruslist.com
- Wells, Joe (August 30, 1996). "Virus timeline". IBM. Archived from the original on June 4, 2008. Retrieved June 6, 2008.
- G Data Software AG (2017). "G Data presents first Antivirus solution in 1987". Archived from the original on March 15, 2017. Retrieved December 13, 2017.
- Karsmakers, Richard (January 2010). "The ultimate Virus Killer Book and Software". Archived from the original on July 29, 2016. Retrieved July 6, 2016.
- "McAfee Becomes Intel Security". McAfee Inc. Retrieved January 15, 2014.
- Cavendish, Marshall (2007). Inventors and Inventions, Volume 4. Paul Bernabeo. p. 1033. ISBN 978-0761477679.
- "About ESET Company". Archived from the original on October 28, 2016.
- "ESET NOD32 Antivirus". Vision Square. February 16, 2016. Archived from the original on February 24, 2016.
- Cohen, Fred, An Undetectable Computer Virus (Archived), 1987, IBM
- Yevics, Patricia A. "Flu Shot for Computer Viruses". americanbar.org. Archived from the original on August 26, 2014.
- Strom, David (April 1, 2010). "How friends help friends on the Internet: The Ross Greenberg Story". wordpress.com. Archived from the original on August 26, 2014.
- "Anti-virus is 30 years old". spgedwards.com. April 2012. Archived from the original on April 27, 2015.
- "A Brief History of Antivirus Software". techlineinfo.com. Archived from the original on August 26, 2014.
- Grimes, Roger A. (June 1, 2001). Malicious Mobile Code: Virus Protection for Windows. O'Reilly Media, Inc. p. 522. ISBN 9781565926820. Archived from the original on March 21, 2017.
- "F-PROT Tækniþjónusta – CYREN Iceland". frisk.is. Archived from the original on June 17, 2006.
- Direccion General del Derecho de Autor, SEP, Mexico D.F. Registry 20709/88 Book 8, page 40, dated November 24, 1988.
- "The 'Security Digest' Archives (TM) : www.phreak.org-virus_l". Archived from the original on January 5, 2010.
- "Symantec Softwares and Internet Security at PCM". Archived from the original on July 1, 2014.
- SAM Identifies Virus-Infected Files, Repairs Applications, InfoWorld, May 22, 1989
- SAM Update Lets Users Program for New Viruses, InfoWorld, February 19, 1990
- Naveen, Sharanya. "Panda Security". Archived from the original on June 30, 2016. Retrieved May 31, 2016.
- "Who we are – TG Soft Software House". www.tgsoft.it. Archived from the original on October 13, 2014.
- "A New Virus Naming Convention (1991) – CARO – Computer Antivirus Research Organization". Archived from the original on August 13, 2011.
- "CARO Members". CARO. Archived from the original on July 18, 2011. Retrieved June 6, 2011.
- CAROids, Hamburg 2003 Archived November 7, 2014, at the Wayback Machine
- "F-Secure Weblog : News from the Lab". F-secure.com. Archived from the original on September 23, 2012. Retrieved September 23, 2012.
- "About EICAR". EICAR official website. Archived from the original on January 23, 2018. Retrieved October 28, 2013.
- David Harley, Lysa Myers & Eddy Willems. "Test Files and Product Evaluation: the Case for and against Malware Simulation" (PDF). AVAR2010 13th Association of anti Virus Asia Researchers International Conference. Archived from the original (PDF) on September 29, 2011. Retrieved June 30, 2011.
- "Dr. Web LTD Doctor Web / Dr. Web Reviews, Best AntiVirus Software Reviews, Review Centre". Reviewcentre.com. Archived from the original on February 23, 2014. Retrieved February 17, 2014.
- [In 1994, AV-Test.org reported 28,613 unique malware samples (based on MD5). "A Brief History of Malware; The First 25 Years"]
- "BitDefender Product History". Archived from the original on March 17, 2012.
- "InfoWatch Management". InfoWatch. Archived from the original on August 21, 2013. Retrieved August 12, 2013.
- "Linuxvirus – Community Help Wiki". Archived from the original on March 24, 2017.
- "Sorry – recovering..." Archived from the original on August 26, 2014.
- "Sourcefire acquires ClamAV". ClamAV. August 17, 2007. Archived from the original on December 15, 2007. Retrieved February 12, 2008.
- "Cisco Completes Acquisition of Sourcefire". cisco.com. October 7, 2013. Archived from the original on January 13, 2015. Retrieved June 18, 2014.
- Der Unternehmer – brand eins online Archived November 22, 2012, at the Wayback Machine. Brandeins.de (July 2009). Retrieved on January 3, 2017.
- Williams, Greg (April 2012). "The digital detective: Mikko Hypponen's war on malware is escalating". Wired. Archived from the original on March 15, 2016.
- "Everyday cybercrime – and what you can do about it". Archived from the original on February 20, 2014.
- Szor 2005, pp. 66–67
- "New virus travels in PDF files". August 7, 2001. Archived from the original on June 16, 2011. Retrieved October 29, 2011.
- Slipstick Systems (February 2009). "Protecting Microsoft Outlook against Viruses". Archived from the original on June 2, 2009. Retrieved June 18, 2009.
- "CloudAV: N-Version Antivirus in the Network Cloud". usenix.org. Archived from the original on August 26, 2014.
- McAfee Artemis Preview Report Archived April 3, 2016, at the Wayback Machine. av-comparatives.org
- McAfee Third Quarter 2008 Archived April 3, 2016, at the Wayback Machine. corporate-ir.net
- "AMTSO Best Practices for Testing In-the-Cloud Security Products » AMTSO". Archived from the original on April 14, 2016.
- "TECHNOLOGY OVERVIEW". AVG Security. Archived from the original on June 2, 2015. Retrieved February 16, 2015.
- "Magic Quadrant Endpoint Protection Platforms 2016". Gartner Research.
- Messmer, Ellen (August 20, 2014). "Start-up offers up endpoint detection and response for behavior-based malware detection". networkworld.com. Archived from the original on February 5, 2015.
- "Homeland Security Today: Bromium Research Reveals Insecurity in Existing Endpoint Malware Protection Deployments". Archived from the original on September 24, 2015.
- "Duelling Unicorns: CrowdStrike Vs. Cylance In Brutal Battle To Knock Hackers Out". Forbes. July 6, 2016. Archived from the original on September 11, 2016.
- Potter, Davitt (June 9, 2016). "Is Anti-virus Dead? The Shift Toward Next-Gen Endpoints". Archived from the original on December 20, 2016.
- "CylancePROTECT® Achieves HIPAA Security Rule Compliance Certification". Cylance. Archived from the original on October 22, 2016.
- "Trend Micro-XGen". Trend Micro. October 18, 2016. Archived from the original on December 21, 2016.
- "Next-Gen Endpoint". Sophos. Archived from the original on November 6, 2016.
- The Forrester Wave™: Endpoint Security Suites, Q4 2016 Archived October 22, 2016, at the Wayback Machine. Forrester.com (October 19, 2016). Retrieved on 2017-01-03.
- Sandboxing Protects Endpoints | Stay Ahead Of Zero Day Threats Archived April 2, 2015, at the Wayback Machine. Enterprise.comodo.com (June 20, 2014). Retrieved on 2017-01-03.
- Szor 2005, pp. 474–481
- Kiem, Hoang; Thuy, Nguyen Yhanh and Quang, Truong Minh Nhat (December 2004) "A Machine Learning Approach to Anti-virus System", Joint Workshop of Vietnamese Society of AI, SIGKBS-JSAI, ICS-IPSJ and IEICE-SIGAI on Active Mining ; Session 3: Artificial Intelligence, Vol. 67, pp. 61–65
- Data Mining Methods for Malware Detection. ProQuest. 2008. pp. 15–. ISBN 978-0-549-88885-7. Archived from the original on March 20, 2017.
- Dua, Sumeet; Du, Xian (April 19, 2016). Data Mining and Machine Learning in Cybersecurity. CRC Press. pp. 1–. ISBN 978-1-4398-3943-0. Archived from the original on March 20, 2017.
- Firdausi, Ivan; Lim, Charles; Erwin, Alva; Nugroho, Anto Satriyo (2010). "Analysis of Machine learning Techniques Used in Behavior-Based Malware Detection". 2010 Second International Conference on Advances in Computing, Control, and Telecommunication Technologies. p. 201. doi:10.1109/ACT.2010.33. ISBN 978-1-4244-8746-2.
- Siddiqui, Muazzam; Wang, Morgan C.; Lee, Joohan (2008). "A survey of data mining techniques for malware detection using file features". Proceedings of the 46th Annual Southeast Regional Conference on XX – ACM-SE 46. p. 509. doi:10.1145/1593105.1593239. ISBN 9781605581057.
- Deng, P.S.; Jau-Hwang Wang; Wen-Gong Shieh; Chih-Pin Yen; Cheng-Tan Tung (2003). "Intelligent automatic malicious code signatures extraction". IEEE 37th Annual 2003 International Carnahan Conference on Security Technology, 2003. Proceedings. p. 600. doi:10.1109/CCST.2003.1297626. ISBN 978-0-7803-7882-7.
- Komashinskiy, Dmitriy; Kotenko, Igor (2010). "Malware Detection by Data Mining Techniques Based on Positionally Dependent Features". 2010 18th Euromicro Conference on Parallel, Distributed and Network-based Processing. p. 617. doi:10.1109/PDP.2010.30. ISBN 978-1-4244-5672-7.
- Schultz, M.G.; Eskin, E.; Zadok, F.; Stolfo, S.J. (2001). "Data mining methods for detection of new malicious executables". Proceedings 2001 IEEE Symposium on Security and Privacy. S&P 2001. p. 38. CiteSeerX 10.1.1.408.5676. doi:10.1109/SECPRI.2001.924286. ISBN 978-0-7695-1046-0.
- Ye, Yanfang; Wang, Dingding; Li, Tao; Ye, Dongyi (2007). "IMDS". Proceedings of the 13th ACM SIGKDD international conference on Knowledge discovery and data mining – KDD '07. p. 1043. doi:10.1145/1281192.1281308. ISBN 9781595936097.
- Kolter, J. Zico; Maloof, Marcus A. (December 1, 2006). "Learning to Detect and Classify Malicious Executables in the Wild". J. Mach. Learn. Res. 7: 2721–2744.
- Tabish, S. Momina; Shafiq, M. Zubair; Farooq, Muddassar (2009). "Malware detection using statistical analysis of byte-level file content". Proceedings of the ACM SIGKDD Workshop on Cyber Security and Intelligence Informatics – CSI-KDD '09. p. 23. CiteSeerX 10.1.1.466.5074. doi:10.1145/1599272.1599278. ISBN 9781605586694.
- Ye, Yanfang; Wang, Dingding; Li, Tao; Ye, Dongyi; Jiang, Qingshan (2008). "An intelligent PE-malware detection system based on association mining". Journal in Computer Virology. 4 (4): 323. CiteSeerX 10.1.1.172.4316. doi:10.1007/s11416-008-0082-4.
- Sami, Ashkan; Yadegari, Babak; Peiravian, Naser; Hashemi, Sattar; Hamze, Ali (2010). "Malware detection based on mining API calls". Proceedings of the 2010 ACM Symposium on Applied Computing – SAC '10. p. 1020. doi:10.1145/1774088.1774303. ISBN 9781605586397.
- Shabtai, Asaf; Kanonov, Uri; Elovici, Yuval; Glezer, Chanan; Weiss, Yael (2011). ""Andromaly": A behavioral malware detection framework for android devices". Journal of Intelligent Information Systems. 38: 161. doi:10.1007/s10844-010-0148-x.
- Fox-Brewster, Thomas. "Netflix Is Dumping Anti-Virus, Presages Death Of An Industry". Forbes. Archived from the original on September 6, 2015. Retrieved September 4, 2015.
- Automatic Malware Signature Generation Archived September 21, 2015, at the Wayback Machine. (PDF) . Retrieved on January 3, 2017.
- Szor 2005, pp. 252–288
- "Generic detection". Kaspersky. Archived from the original on December 3, 2013. Retrieved July 11, 2013.
- Symantec Corporation (February 2009). "Trojan.Vundo". Archived from the original on April 9, 2009. Retrieved April 14, 2009.
- Symantec Corporation (February 2007). "Trojan.Vundo.B". Archived from the original on April 27, 2009. Retrieved April 14, 2009.
- "Antivirus Research and Detection Techniques". ExtremeTech. Archived from the original on February 27, 2009. Retrieved February 24, 2009.
- "Terminology – F-Secure Labs". Archived from the original on August 24, 2010.
- Kaspersky Lab Technical Support Portal Archived February 14, 2011, at WebCite
- Kelly, Michael (October 2006). "Buying Dangerously". Archived from the original on July 15, 2010. Retrieved November 29, 2009.
- Bitdefender (2009). "Automatic Renewal". Archived from the original on October 6, 2009. Retrieved November 29, 2009.
- Symantec (2014). "Norton Automatic Renewal Service FAQ". Archived from the original on April 13, 2014. Retrieved April 9, 2014.
- SpywareWarrior (2007). "Rogue/Suspect Anti-Spyware Products & Web Sites". Retrieved November 29, 2009.
- Protalinski, Emil (November 11, 2008). "AVG incorrectly flags user32.dll in Windows XP SP2/SP3". Ars Technica. Archived from the original on April 30, 2011. Retrieved February 24, 2011.
- McAfee to compensate businesses for buggy update, archived from the original on September 4, 2010, retrieved December 2, 2010
- Buggy McAfee update whacks Windows XP PCs, archived from the original on January 13, 2011, retrieved December 2, 2010
- Tan, Aaron (May 24, 2007). "Flawed Symantec update cripples Chinese PCs". CNET Networks. Archived from the original on April 26, 2011. Retrieved April 5, 2009.
- Harris, David (June 29, 2009). "January 2010 – Pegasus Mail v4.52 Release". Pegasus Mail. Archived from the original on May 28, 2010. Retrieved May 21, 2010.
- "McAfee DAT 5958 Update Issues". April 21, 2010. Archived from the original on April 24, 2010. Retrieved April 22, 2010.
- "Botched McAfee update shutting down corporate XP machines worldwide". April 21, 2010. Archived from the original on April 22, 2010. Retrieved April 22, 2010.
- Leyden, John (December 2, 2010). "Horror AVG update ballsup bricks Windows 7". The Register. Archived from the original on December 5, 2010. Retrieved December 2, 2010.
- MSE false positive detection forces Google to update Chrome, October 3, 2011, archived from the original on October 4, 2011, retrieved October 3, 2011
- Sophos Antivirus Detects Itself as Malware, Deletes Key Binaries, The Next Web, September 20, 2012, archived from the original on January 17, 2014, retrieved March 5, 2014
- Shh/Updater-B false positive by Sophos anti-virus products, Sophos, September 19, 2012, archived from the original on April 21, 2014, retrieved March 5, 2014
- If Google Play Protect is breaking bluetooth on your Moto G4 Plus, don't worry because there's a fix, Android Police, September 11, 2017, archived from the original on November 7, 2017, retrieved November 1, 2017
- "Plus! 98: How to Remove McAfee VirusScan". Microsoft. January 2007. Archived from the original on April 8, 2010. Retrieved September 27, 2014.
- Vamosi, Robert (May 28, 2009). "G-Data Internet Security 2010". PC World. Archived from the original on February 11, 2011. Retrieved February 24, 2011.
- Higgins, Kelly Jackson (May 5, 2010). "New Microsoft Forefront Software Runs Five Antivirus Vendors' Engines". Darkreading. Archived from the original on May 12, 2010. Retrieved February 24, 2011.
- "Steps to take before you install Windows XP Service Pack 3". Microsoft. April 2009. Archived from the original on December 8, 2009. Retrieved November 29, 2009.
- "Upgrading from Windows Vista to Windows 7". Archived from the original on November 30, 2011. Retrieved March 24, 2012. Mentioned within "Before you begin".
- "Upgrading to Microsoft Windows Vista recommended steps". Archived from the original on March 8, 2012. Retrieved March 24, 2012.
- "How to troubleshoot problems during installation when you upgrade from Windows 98 or Windows Millennium Edition to Windows XP". May 7, 2007. Archived from the original on March 9, 2012. Retrieved March 24, 2012. Mentioned within "General troubleshooting".
- "BT Home Hub Firmware Upgrade Procedure". Archived from the original on May 12, 2011. Retrieved March 6, 2011.
- "Troubleshooting". Retrieved February 17, 2011.
- "Spyware, Adware, and Viruses Interfering with Steam". Archived from the original on July 1, 2013. Retrieved April 11, 2013. Steam support page.
- "Field Notice: FN – 63204 – Cisco Clean Access has Interoperability issue with Symantec Anti-virus – delays Agent start-up". Archived from the original on September 24, 2009.
- Goodin, Dan (December 21, 2007). "Anti-virus protection gets worse". Channel Register. Archived from the original on May 11, 2011. Retrieved February 24, 2011.
- "ZeuS Tracker :: Home". Archived from the original on November 3, 2010.
- Illett, Dan (July 13, 2007). "Hacking poses threats to business". Computer Weekly. Archived from the original on January 12, 2010. Retrieved November 15, 2009.
- Espiner, Tom (June 30, 2008). "Trend Micro: Antivirus industry lied for 20 years". ZDNet. Archived from the original on October 6, 2014. Retrieved September 27, 2014.
- AV Comparatives (December 2013). "Whole Product Dynamic "Real World" Production Test" (PDF). Archived (PDF) from the original on January 2, 2014. Retrieved January 2, 2014.
- Kirk, Jeremy (June 14, 2010). "Guidelines released for antivirus software tests". Archived from the original on April 22, 2011.
- Harley, David (2011). AVIEN Malware Defense Guide for the Enterprise. Elsevier. p. 487. ISBN 9780080558660. Archived from the original on January 3, 2014.
- Kotadia, Munir (July 2006). "Why popular antivirus apps 'do not work'". Archived from the original on April 30, 2011. Retrieved April 14, 2010.
- The Canadian Press (April 2010). "Internet scam uses adult game to extort cash". CBC News. Archived from the original on April 18, 2010. Retrieved April 17, 2010.
- Exploit Code; Data Theft; Information Security; Privacy; Hackers; system, Security mandates aim to shore up shattered SSL; Reader, Adobe kills two actively exploited bugs in; stalker, Judge dismisses charges against accused Twitter. "Researchers up evilness ante with GPU-assisted malware". Archived from the original on August 10, 2017.
- Iresh, Gina (April 10, 2010). "Review of Bitdefender Antivirus Security Software 2017 edition". www.digitalgrog.com.au. Digital Grog. Archived from the original on November 21, 2016. Retrieved November 20, 2016.
- "Why F-PROT Antivirus fails to disinfect the virus on my computer?". Archived from the original on September 17, 2015. Retrieved August 20, 2015.
- "Actions to be performed on infected objects". Archived from the original on August 9, 2015. Retrieved August 20, 2015.
- "Cryptolocker Ransomware: What You Need To Know". October 8, 2013. Archived from the original on February 9, 2014. Retrieved March 28, 2014.
- "How Anti-Virus Software Works". Archived from the original on March 2, 2011. Retrieved February 16, 2011.
- "The 10 faces of computer malware". July 17, 2009. Archived from the original on February 9, 2011. Retrieved March 6, 2011.
- "New BIOS Virus Withstands HDD Wipes". March 27, 2009. Archived from the original on April 1, 2011. Retrieved March 6, 2011.
- "Phrack Inc. Persistent BIOS Infection". June 1, 2009. Archived from the original on April 30, 2011. Retrieved March 6, 2011.
- "Turning USB peripherals into BadUSB". Archived from the original on April 18, 2016. Retrieved October 11, 2014.
- "Why the Security of USB Is Fundamentally Broken". Wired. July 31, 2014. Archived from the original on August 3, 2014. Retrieved October 11, 2014.
- "How Antivirus Software Can Slow Down Your Computer". Support.com Blog. Archived from the original on September 29, 2012. Retrieved July 26, 2010.
- "Softpedia Exclusive Interview: Avira 10". Ionut Ilascu. Softpedia. April 14, 2010. Archived from the original on August 26, 2011. Retrieved September 11, 2011.
- "Norton AntiVirus ignores malicious WMI instructions". Munir Kotadia. CBS Interactive. October 21, 2004. Archived from the original on September 12, 2009. Retrieved April 5, 2009.
- "NSA and GCHQ attacked antivirus software so that they could spy on people, leaks indicate". June 24, 2015. Retrieved October 30, 2016.
- "Popular security software came under relentless NSA and GCHQ attacks". Andrew Fishman, Morgan Marquis-Boire. June 22, 2015. Archived from the original on October 31, 2016. Retrieved October 30, 2016.
- Zeltser, Lenny (October 2010). "What Is Cloud Anti-Virus and How Does It Work?". Archived from the original on October 10, 2010. Retrieved October 26, 2010.
- Erickson, Jon (August 6, 2008). "Antivirus Software Heads for the Clouds". Information Week. Archived from the original on April 26, 2011. Retrieved February 24, 2010.
- "Comodo Cloud Antivirus released". wikipost.org. Archived from the original on May 17, 2016. Retrieved May 30, 2016.
- "Comodo Cloud Antivirus User Guideline PDF" (PDF). help.comodo.com. Archived (PDF) from the original on June 4, 2016. Retrieved May 30, 2016.
- Krebs, Brian (March 9, 2007). "Online Anti-Virus Scans: A Free Second Opinion". Washington Post. Retrieved February 24, 2011.
- "Avast Free Anti-Malware". AVAST Software. Retrieved May 1, 2018.
- "Free Virus Scanner & Malware Removal Tools". AVG Technologies. Retrieved May 1, 2018.
- "Download Avira AntiVir Removal Tool". Avira Operations GmbH & Co. KG. Retrieved May 1, 2018.
- "How To Tell If a Virus Is Actually a False Positive". How To Geek. Retrieved October 2, 2018.
- "How to create a Bitdefender Rescue CD". Bitdefender. Retrieved June 1, 2018.
- "Disinfect the operating system". Kaspersky Lab. Retrieved June 1, 2018.
- "Help protect my PC with Windows Defender Offline". Microsoft Corporation. Retrieved June 1, 2018.
- "FBI estimates major companies lose $12m annually from viruses". January 30, 2007. Retrieved February 20, 2011.
- Kaiser, Michael (April 17, 2009). "Small and Medium Size Businesses are Vulnerable". National Cyber Security Alliance. Archived from the original on April 22, 2011. Retrieved February 24, 2011.
- Nearly 50% Women Don’t Use Anti-virus Software Archived May 13, 2013, at the Wayback Machine. Spamfighter.com (September 2, 2010). Retrieved on January 3, 2017.