In programming and information security, a buffer overflow or buffer overrun is an anomaly whereby a program writes data to a buffer beyond the buffer's allocated memory, overwriting adjacent memory locations.
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.
The Morris worm or Internet worm of November 2, 1988, is one of the oldest computer worms distributed via the Internet, and the first to gain significant mainstream media attention. It resulted in the first felony conviction in the US under the 1986 Computer Fraud and Abuse Act. It was written by a graduate student at Cornell University, Robert Tappan Morris, and launched on 8:30 pm November 2, 1988, from the Massachusetts Institute of Technology network.
SQL Slammer is a 2003 computer worm that caused a denial of service on some Internet hosts and dramatically slowed general Internet traffic. It also crashed routers around the world, causing even more slowdowns. It spread rapidly, infecting most of its 75,000 victims within 10 minutes.
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.
Blaster was a computer worm that spread on computers running operating systems Windows XP and Windows 2000 during August 2003.
Mydoom was a computer worm that targeted computers running Microsoft Windows. It was first sighted on January 26, 2004. It became the fastest-spreading e-mail worm ever, exceeding previous records set by the Sobig worm and ILOVEYOU, a record which as of 2024 has yet to be surpassed.
Code Red II is a computer worm similar to the Code Red worm. Released two weeks after Code Red on August 4, 2001, it is similar in behavior to the original, but analysis showed it to be a new worm instead of a variant. Unlike the first, the second has no function for attack; instead it has a backdoor that allows attacks. The worm was designed to exploit a security hole in the indexing software included as part of Microsoft's Internet Information Server (IIS) web server software.
Sasser is a computer worm that affects computers running vulnerable versions of the Microsoft operating systems Windows XP and Windows 2000. Sasser spreads by exploiting the system through a vulnerable port. Thus it is particularly virulent in that it can spread without user intervention, but it is also easily stopped by a properly configured firewall or by downloading system updates from Windows Update. The specific hole Sasser exploits is documented by Microsoft in its MS04-011 bulletin, for which a patch had been released seventeen days earlier. The most characteristic experience of the worm is the shutdown timer that appears due to the worm crashing LSASS.
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.
Agobot, also frequently known as Gaobot, is a family of computer worms. Axel "Ago" Gembe, a German programmer also known for leaking Half-Life 2 a year before release, was responsible for writing the first version. The Agobot source code describes it as: “a modular IRC bot for Win32 / Linux”. Agobot was released under version 2 of the GNU General Public License. Agobot is a multi-threaded and mostly object oriented program written in C++ as well as a small amount of assembly. Agobot is an example of a Botnet that requires little or no programming knowledge to use.
Welchia, also known as the "Nachi worm", is a computer worm that exploits a vulnerability in the Microsoft remote procedure call (RPC) service similar to the Blaster worm. However, unlike Blaster, it first searches for and deletes Blaster if it exists, then tries to download and install security patches from Microsoft that would prevent further infection by Blaster, so it is classified as a helpful worm. Welchia was successful in deleting Blaster, but Microsoft claimed that it was not always successful in applying their security patch.
Zotob is a computer worm which exploits security vulnerabilities in Microsoft operating systems like Windows 2000, including the MS05-039 plug-and-play vulnerability. This worm has been known to spread on Microsoft-ds or TCP port 445.
The Sadmind worm was a computer worm which exploited vulnerabilities in both Sun Microsystems' Solaris and Microsoft's Internet Information Services, for which a patch had been made available seven months earlier. It was discovered on May 8, 2001.
The Witty worm was a computer worm that attacked the firewall and other computer security products written by a particular company, the Internet Security Systems (ISS) now IBM Internet Security Systems. It was the first worm to take advantage of vulnerabilities in the very pieces of software designed to enhance network security, and carried a destructive payload, unlike previous worms. It is so named because the phrase "(^.^) insert witty message here (^.^)" appears in the worm's payload.
The Nimda virus is a malicious file-infecting computer worm. It quickly spread, surpassing the economic damage caused by previous outbreaks such as Code Red.
In computer science, attack patterns are a group of rigorous methods for finding bugs or errors in code related to computer security.
In software, a stack buffer overflow or stack buffer overrun occurs when a program writes to a memory address on the program's call stack outside of the intended data structure, which is usually a fixed-length buffer. Stack buffer overflow bugs are caused when a program writes more data to a buffer located on the stack than what is actually allocated for that buffer. This almost always results in corruption of adjacent data on the stack, and in cases where the overflow was triggered by mistake, will often cause the program to crash or operate incorrectly. Stack buffer overflow is a type of the more general programming malfunction known as buffer overflow. Overfilling a buffer on the stack is more likely to derail program execution than overfilling a buffer on the heap because the stack contains the return addresses for all active function calls.
Conficker, also known as Downup, Downadup and Kido, is a computer worm targeting the Microsoft Windows operating system that was first detected in November 2008. It uses flaws in Windows OS software and dictionary attacks on administrator passwords to propagate while forming a botnet, and has been unusually difficult to counter because of its combined use of many advanced malware techniques. The Conficker worm infected millions of computers including government, business and home computers in over 190 countries, making it the largest known computer worm infection since the 2003 SQL Slammer worm.
