Timeline of notable computer viruses and worms — period pre-antivirus days [ edit ] Although the roots of the computer virus date back as early as , when the Hungarian scientist John von Neumann published the "Theory of self-reproducing automata",  the first known computer virus appeared in and was dubbed the " Creeper virus ".
The first known that appeared "in the wild" was " Elk Cloner ", in , which infected Apple II computers. From then, the number of viruses has grown exponentially. 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.
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. Possibly, the first publicly documented removal of an "in the wild" computer virus i. 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 , the growth of antivirus companies continued.
In Bulgaria , Dr. In June , in South Korea , Dr. Solomon's Anti-Virus Toolkit although he launched it commercially only in — in Dr. Carriles copyrighted the first antivirus software in Mexico under the name "Byte Matabichos" Byte Bugkiller to help solve the rampant virus infestation among students.
Some members of this mailing list were: In the same period, in Hungary, also VirusBuster was founded which has recently being incorporated by Sophos. On the other hand, in Finland , F-Secure founded in 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. 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. A user's computer could be infected by just opening or previewing a message. Given the consideration that most of the people is nowadays connected to the Internet round-the-clock, in , Jon Oberheide first proposed a Cloud-based antivirus design. 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. 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. Cohen's demonstration that there is no algorithm that can perfectly detect all possible viruses.
There are several methods which antivirus engine can use to identify malware: Depending on the actions logged, the antivirus engine can determine if the program is malicious or not. 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 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.
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. Generic detection refers to the detection and removal of multiple threats using a single virus definition. Symantec classifies members of the Vundo family into two distinct categories, Trojan.
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. Rootkit 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. 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: 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.
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. Norton AntiVirus had falsely identified three releases of Pegasus Mail as malware, and would delete the Pegasus Mail installer file when that happened.
MSE flagged Chrome as a Zbot banking trojan. If it was configured to automatically delete detected files, Sophos Antivirus could render itself unable to update, required manual intervention to fix the problem. It is sometimes necessary to temporarily disable virus protection when installing major updates such as Windows Service Packs or updating graphics card drivers.
Anti-virus software can cause problems during the installation of an operating system upgrade, e. Microsoft recommends that anti-virus software be disabled to avoid conflicts with the upgrade installation process. 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. 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.
Effectiveness[ edit ] Studies in December showed that the effectiveness of antivirus software had decreased in the previous year, particularly against unknown or zero day attacks. 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. The best ones provided as high as Many virus scanners produce false positive results as well, identifying benign files as malware. 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.
Jerome Segura, a security analyst with ParetoLogic, explained: 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. 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. 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. Firmware infections[ edit ] Any writeable firmware in the computer can be infected by malicious code.
The malicious code can run undetected on the computer and could even infect the operating system prior to it booting up. 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. Although installed antivirus solutions running on individual computers are the most common, this is only one method of guarding against malware. Other solutions are also used, including Unified Threat Management UTM , hardware and network firewalls, Cloud-based antivirus, and online scanners.
Hardware and network firewall[ edit ] 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. 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[ edit ] 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. 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. 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. 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.