Malware is any software intentionally designed to cause disruption to a computer, server, client, or computer network, leak private information, gain unauthorized access to information or systems, deprive access to information, or which unknowingly interferes with the user's computer security and privacy. Researchers tend to classify malware into one or more sub-types.
In computing terminology, a macro virus is a virus that is written in a macro language: a programming language which is embedded inside a software application. Some applications, such as Microsoft Office, Excel, PowerPoint allow macro programs to be embedded in documents such that the macros are run automatically when the document is opened, and this provides a distinct mechanism by which malicious computer instructions can spread. This is one reason it can be dangerous to open unexpected attachments in e-mails. Many antivirus programs can detect macro viruses; however, the macro virus' behavior can still be difficult to detect.
This timeline of computer viruses and worms presents a chronological timeline of noteworthy computer viruses, computer worms, Trojan horses, similar malware, related research and events.
ESET, s.r.o., is a Slovak software company specializing in cybersecurity. ESET's security products are made in Europe and provide security software in over 200 countries and territories worldwide, and its software is localized into more than 30 languages.
Ransomware is a type of cryptovirological malware that threatens to publish the victim's personal data or permanently block access to it unless a ransom is paid. While some simple ransomware may lock the system without damaging any files, more advanced malware uses a technique called cryptoviral extortion. It encrypts the victim's files, making them inaccessible, and demands a ransom payment to decrypt them. In a properly implemented cryptoviral extortion attack, recovering the files without the decryption key is an intractable problem, and difficult to trace digital currencies such as paysafecard or Bitcoin and other cryptocurrencies are used for the ransoms, making tracing and prosecuting the perpetrators difficult.
Cryptovirology refers to the use of cryptography to devise particularly powerful malware, such as ransomware and asymmetric backdoors. Traditionally, cryptography and its applications are defensive in nature, and provide privacy, authentication, and security to users. Cryptovirology employs a twist on cryptography, showing that it can also be used offensively. It can be used to mount extortion based attacks that cause loss of access to information, loss of confidentiality, and information leakage, tasks which cryptography typically prevents.
A computer virus is a type of malware that, when executed, replicates itself by modifying other computer programs and inserting its own code into those programs. If this replication succeeds, the affected areas are then said to be "infected" with a computer virus, a metaphor derived from biological viruses.
Malvertising is the use of online advertising to spread malware. It typically involves injecting malicious or malware-laden advertisements into legitimate online advertising networks and webpages. Because advertising content can be inserted into high-profile and reputable websites, malvertising provides malefactors an opportunity to push their attacks to web users who might not otherwise see the ads, due to firewalls, more safety precautions, or the like. Malvertising is "attractive to attackers because they 'can be easily spread across a large number of legitimate websites without directly compromising those websites'."
The CryptoLocker ransomware attack was a cyberattack using the CryptoLocker ransomware that occurred from 5 September 2013 to late May 2014. The attack utilized a trojan that targeted computers running Microsoft Windows, and was believed to have first been posted to the Internet on 5 September 2013. It propagated via infected email attachments, and via an existing Gameover ZeuS botnet. When activated, the malware encrypted certain types of files stored on local and mounted network drives using RSA public-key cryptography, with the private key stored only on the malware's control servers. The malware then displayed a message which offered to decrypt the data if a payment was made by a stated deadline, and it threatened to delete the private key if the deadline passes. If the deadline was not met, the malware offered to decrypt data via an online service provided by the malware's operators, for a significantly higher price in bitcoin. There was no guarantee that payment would release the encrypted content.
TeslaCrypt was a ransomware trojan. It is now defunct, and its master key was released by the developers.
Linux.Encoder is considered to be the first ransomware Trojan targeting computers running Linux. There are additional variants of this Trojan that target other Unix and Unix-like systems. Discovered on November 5, 2015, by Dr. Web, this malware affected at least tens of Linux users.
KeRanger is a ransomware trojan horse targeting computers running macOS. Discovered on March 4, 2016, by Palo Alto Networks, it affected more than 7,000 Mac users.
Dridex, also known as Bugat and Cridex, is a form of malware that specializes in stealing bank credentials via a system that utilizes macros from Microsoft Word.
The Necurs botnet is a distributor of many pieces of malware, most notably Locky.
Numbered Panda is a cyber espionage group believed to be linked with the Chinese military. The group typically targets organizations in East Asia. These organizations include, but are not limited to, media outlets, high-tech companies, and governments. Numbered Panda is believed to have been operating since 2009. However, the group is also credited with a 2012 data breach at the New York Times. One of the group's typical techniques is to send PDF files loaded with malware via spear phishing campaigns. The decoy documents are typically written in traditional Chinese, which is widely used in Taiwan, and the targets are largely associated with Taiwanese interests. Numbered Panda appears to be actively seeking out cybersecurity research relating to the malware they use. After an Arbor Networks report on the group, FireEye noticed a change in the group's techniques to avoid future detection.
Emotet is a malware strain and a cybercrime operation believed to be based in Ukraine. The malware, also known as Heodo, was first detected in 2014 and deemed one of the most prevalent threats of the decade. In 2021, the servers used for Emotet were disrupted through global police action in Germany and Ukraine and brought under the control of law enforcement.
Hitler-Ransomware, or Hitler-Ransonware [sic], is a form of ransomware created in 2016 originating in Germany. It requests payment within one hour; otherwise, it will delete files from the infected computer.
Jigsaw is a form of encrypting ransomware malware created in 2016. It was initially titled "BitcoinBlackmailer", but later came to be known as "Jigsaw" due to featuring an image of Billy the Puppet from the Saw film franchise. The malware encrypts computer files and gradually deletes them, demanding payment of a ransom to decrypt the files and halt the deletion.
Ryuk is a type of ransomware known for targeting large, public-entity Microsoft Windows cybersystems. It typically encrypts data on an infected system, rendering the data inaccessible until a ransom is paid in untraceable bitcoin. Ryuk is believed to be used by two or more criminal groups, most likely Russian, who target organizations rather than individual consumers.
Clop is a cybercriminal organization known for its multilevel extortion techniques and global malware distribution. It has extorted more than $500 million in ransom payments, targeting major organizations worldwide. Clop gained notoriety in 2019 and has since conducted high-profile attacks, using large-scale phishing campaigns and sophisticated malware to infiltrate networks and demand ransom, threatening to expose data if demands are not met.
