A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. It often uses a computer network to spread itself, relying on security failures on the target computer to access it. It will use this machine as a host to scan and infect other computers. When these new worm-invaded computers are controlled, the worm will continue to scan and infect other computers using these computers as hosts, and this behaviour will continue. Computer worms use recursive methods to copy themselves without host programs and distribute themselves based on exploiting the advantages of exponential growth, thus controlling and infecting more and more computers in a short time. Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.
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.
In computing, a Trojan horse is any malware that misleads users of its true intent by disguising itself as a standard program. The term is derived from the ancient Greek story of the deceptive Trojan Horse that led to the fall of the city of Troy.
Blaster was a computer worm that spread on computers running operating systems Windows XP and Windows 2000 during August 2003.
Linux malware includes viruses, Trojans, worms and other types of malware that affect the Linux family of operating systems. Linux, Unix and other Unix-like computer operating systems are generally regarded as very well-protected against, but not immune to, computer viruses.
In computing, Download.ject is a malware program for Microsoft Windows servers. When installed on an insecure website running on Microsoft Internet Information Services (IIS), it appends malicious JavaScript to all pages served by the site.
Ransomware is a type of cryptovirological malware that permanently blocks access to the victim's personal data 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.
Mobile malware is malicious software that targets mobile phones or wireless-enabled Personal digital assistants (PDA), by causing the collapse of the system and loss or leakage of confidential information. As wireless phones and PDA networks have become more and more common and have grown in complexity, it has become increasingly difficult to ensure their safety and security against electronic attacks in the form of viruses or other malware.
WinFixer was a family of scareware rogue security programs developed by Winsoftware which claimed to repair computer system problems on Microsoft Windows computers if a user purchased the full version of the software. The software was mainly installed without the user's consent. McAfee claimed that "the primary function of the free version appears to be to alarm the user into paying for registration, at least partially based on false or erroneous detections." The program prompted the user to purchase a paid copy of the program.
The Vundo Trojan is either a Trojan horse or a computer worm that is known to cause popups and advertising for rogue antispyware programs, and sporadically other misbehavior including performance degradation and denial of service with some websites including Google and Facebook. It also is used to deliver other malware to its host computers. Later versions include rootkits and ransomware.
Man-in-the-browser, a form of Internet threat related to man-in-the-middle (MITM), is a proxy Trojan horse that infects a web browser by taking advantage of vulnerabilities in browser security to modify web pages, modify transaction content or insert additional transactions, all in a covert fashion invisible to both the user and host web application. A MitB attack will be successful irrespective of whether security mechanisms such as SSL/PKI and/or two- or three-factor authentication solutions are in place. A MitB attack may be countered by using out-of-band transaction verification, although SMS verification can be defeated by man-in-the-mobile (MitMo) malware infection on the mobile phone. Trojans may be detected and removed by antivirus software;, but a 2011 report concluded that additional measures on top of antivirus software were needed.
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.
Koobface is a network worm that attacks Microsoft Windows, Mac OS X, and Linux platforms. This worm originally targeted users of networking websites like Facebook, Skype, Yahoo Messenger, and email websites such as GMail, Yahoo Mail, and AOL Mail. It also targets other networking websites, such as MySpace, Twitter, and it can infect other devices on the same local network. Technical support scammers also fraudulently claim to their intended victims that they have a Koobface infection on their computer by using fake popups and using built-in Windows programs.
Duqu is a collection of computer malware discovered on 1 September 2011, thought by Kaspersky Labs to be related to the Stuxnet worm and to have been created by Unit 8200. Duqu has exploited Microsoft Windows's zero-day vulnerability. The Laboratory of Cryptography and System Security of the Budapest University of Technology and Economics in Hungary discovered the threat, analysed the malware, and wrote a 60-page report naming the threat Duqu. Duqu got its name from the prefix "~DQ" it gives to the names of files it creates.
Slenfbot is the classification for a family of malicious software (malware), which infects files on Microsoft Windows systems. Slenfbot was first discovered in 2007 and, since then, numerous variants have followed; each with slightly different characteristics and new additions to the worm's payload, such as the ability to provide the attacker with unauthorized access to the compromised host. Slenfbot primarily spreads by luring users to follow links to websites, which contain a malicious payload. Slenfbot propagates via instant messaging applications, removable drives and/or the local network via network shares. The code for Slenfbot appears to be closely managed, which may provide attribution to a single group and/or indicate that a large portion of the code is shared amongst multiple groups. The inclusion of other malware families and variants as well as its own continuous evolution, makes Slenfbot a highly effective downloader with a propensity to cause even more damage to compromised systems.
macOS malware includes viruses, trojan horses, worms and other types of malware that affect macOS, Apple's current operating system for Macintosh computers. macOS is said to rarely suffer malware or virus attacks, and has been considered less vulnerable than Windows. There is a frequent release of system software updates to resolve vulnerabilities. Utilities are also available to find and remove malware.
The WannaCry ransomware attack was a worldwide cyberattack in May 2017 by the WannaCry ransomware cryptoworm, which targeted computers running the Microsoft Windows operating system by encrypting data and demanding ransom payments in the Bitcoin cryptocurrency. It propagated by using EternalBlue, an exploit developed by the United States National Security Agency (NSA) for Windows systems. EternalBlue was stolen and leaked by a group called The Shadow Brokers a month prior to the attack. While Microsoft had released patches previously to close the exploit, much of WannaCry's spread was from organizations that had not applied these, or were using older Windows systems that were past their end-of-life. These patches were imperative to cyber security, but many organizations did not apply them, citing a need for 24/7 operation, the risk of formerly working applications breaking because of the changes, lack of personnel or time to install them, or other reasons.
EternalBlue is computer exploit software developed by the U.S. National Security Agency (NSA). It is based on a vulnerability in Microsoft Windows that, at the time, allowed users to gain access to any number of computers connected to a network. The NSA had known about this vulnerability for several years but had not disclosed it to Microsoft yet, since they planned to use it as a defense mechanism against cyber attacks. In 2017, the NSA discovered that the software was stolen by a group of hackers known as the Shadow Brokers. Microsoft was informed of this and released security updates in March 2017 patching the vulnerability. While this was happening, the hacker group attempted to auction off the software, but did not succeed in finding a buyer. EternalBlue was then publicly released on April 14, 2017.
DoublePulsar is a backdoor implant tool developed by the U.S. National Security Agency's (NSA) Equation Group that was leaked by The Shadow Brokers in early 2017. The tool infected more than 200,000 Microsoft Windows computers in only a few weeks, and was used alongside EternalBlue in the May 2017 WannaCry ransomware attack. A variant of DoublePulsar was first seen in the wild in March 2016, as discovered by Symantec.
