Exploit (computer security)
Encyclopedia
An exploit is a piece of software, a chunk of data, or sequence of commands that takes advantage of a bug
, glitch
or vulnerability in order to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic (usually computerised). This frequently includes such things as gaining control of a computer system or allowing privilege escalation
or a denial-of-service attack
.
. Exploits against client applications also exist, usually consisting of modified servers that send an exploit if accessed with client application. Exploits against client applications may also require some interaction with the user and thus may be used in combination with social engineering method. This is the hacker way of getting into computers and websites for stealing data.
Another classification is by the action against vulnerable system: unauthorized
data access
, arbitrary code execution, denial of service.
Many exploits are designed to provide superuser
-level access to a computer system. However, it is also possible to use several exploits, first to gain low-level access, then to escalate privileges repeatedly until one reaches root.
Normally a single exploit can only take advantage of a specific software vulnerability. Often, when an exploit is published, the vulnerability is fixed through a patch
and the exploit becomes obsolete for newer versions of the software. This is the reason why some blackhat hackers
do not publish their exploits but keep them private to themselves or other hackers. Such exploits are referred to as 'zero day exploits' and to obtain access to such exploits is the primary desire of unskilled attackers, often nicknamed script kiddie
s.
ers that uses compromised system to attack other systems on the same network to avoid restrictions such as firewall configurations, which may prohibit direct access to all machines. For example, an attacker compromises a web server on a corporate network, the attacker can then use the compromised web server to attack other systems on the network. These types of attacks are often called multi-layered attacks. Pivoting is also known as island hopping.
Pivoting can further be distinguished into proxy pivoting and VPN pivoting:
Typically, the proxy or VPN applications enabling pivoting are executed on the target computer as the payload (software)
of an exploit.
Software bug
A software bug is the common term used to describe an error, flaw, mistake, failure, or fault in a computer program or system that produces an incorrect or unexpected result, or causes it to behave in unintended ways. Most bugs arise from mistakes and errors made by people in either a program's...
, glitch
Glitch
A glitch is a short-lived fault in a system. It is often used to describe a transient fault that corrects itself, and is therefore difficult to troubleshoot...
or vulnerability in order to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic (usually computerised). This frequently includes such things as gaining control of a computer system or allowing privilege escalation
Privilege escalation
Privilege escalation is the act of exploiting a bug, design flaw or configuration oversight in an operating system or software application to gain elevated access to resources that are normally protected from an application or user...
or a denial-of-service attack
Denial-of-service attack
A denial-of-service attack or distributed denial-of-service attack is an attempt to make a computer resource unavailable to its intended users...
.
Classification
There are several methods of classifying exploits. The most common is by how the exploit contacts the vulnerable software. A 'remote exploit' works over a network and exploits the security vulnerability without any prior access to the vulnerable system. A 'local exploit' requires prior access to the vulnerable system and usually increases the privileges of the person running the exploit past those granted by the system administratorSystem administrator
A system administrator, IT systems administrator, systems administrator, or sysadmin is a person employed to maintain and operate a computer system and/or network...
. Exploits against client applications also exist, usually consisting of modified servers that send an exploit if accessed with client application. Exploits against client applications may also require some interaction with the user and thus may be used in combination with social engineering method. This is the hacker way of getting into computers and websites for stealing data.
Another classification is by the action against vulnerable system: unauthorized
Authorization
Authorization is the function of specifying access rights to resources, which is related to information security and computer security in general and to access control in particular. More formally, "to authorize" is to define access policy...
data access
Data access
Data access typically refers to software and activities related to storing, retrieving, or acting on data housed in a database or other repository...
, arbitrary code execution, denial of service.
Many exploits are designed to provide superuser
Superuser
On many computer operating systems, the superuser is a special user account used for system administration. Depending on the operating system, the actual name of this account might be: root, administrator or supervisor....
-level access to a computer system. However, it is also possible to use several exploits, first to gain low-level access, then to escalate privileges repeatedly until one reaches root.
Normally a single exploit can only take advantage of a specific software vulnerability. Often, when an exploit is published, the vulnerability is fixed through a patch
Patch (computing)
A patch is a piece of software designed to fix problems with, or update a computer program or its supporting data. This includes fixing security vulnerabilities and other bugs, and improving the usability or performance...
and the exploit becomes obsolete for newer versions of the software. This is the reason why some blackhat hackers
Black hat
A black hat is the villain or bad guy, especially in a western movie in which such a character would stereotypically wear a black hat in contrast to the hero's white hat, especially in black and white movies....
do not publish their exploits but keep them private to themselves or other hackers. Such exploits are referred to as 'zero day exploits' and to obtain access to such exploits is the primary desire of unskilled attackers, often nicknamed script kiddie
Script kiddie
A script kiddie or skiddie, occasionally skid, script bunny, script kitty, script-running juvenile or similar, is a derogatory term used to describe those who use scripts or programs developed by others to attack computer systems and networks and deface websites.-Characteristics:In a Carnegie...
s.
Types
Exploits are commonly categorized and named by these criteria:- The type of vulnerability they exploit (See the article on vulnerabilitiesVulnerability (computing)In computer security, a vulnerability is a weakness which allows an attacker to reduce a system's information assurance.Vulnerability is the intersection of three elements: a system susceptibility or flaw, attacker access to the flaw, and attacker capability to exploit the flaw...
for a list) - Whether they need to be run on the same machine as the program that has the vulnerability (local) or can be run on one machine to attack a program running on another machine (remote).
- The result of running the exploit (EoP, DoS, SpoofingSpoofing attackIn the context of network security, a spoofing attack is a situation in which one person or program successfully masquerades as another by falsifying data and thereby gaining an illegitimate advantage.- Spoofing and TCP/IP :...
, etc.)
Pivoting
Pivoting refers to method used by penetration testPenetration test
A penetration test, occasionally pentest, is a method of evaluating the security of a computer system or network by simulating an attack from malicious outsiders and malicious insiders...
ers that uses compromised system to attack other systems on the same network to avoid restrictions such as firewall configurations, which may prohibit direct access to all machines. For example, an attacker compromises a web server on a corporate network, the attacker can then use the compromised web server to attack other systems on the network. These types of attacks are often called multi-layered attacks. Pivoting is also known as island hopping.
Pivoting can further be distinguished into proxy pivoting and VPN pivoting:
- Proxy pivoting generally describes the practice channeling traffic through a compromised target using a proxy payload on the machine and launching attacks from this computer. This type of pivoting is restricted to certain TCP and UDP ports that are supported by the proxy.
- VPN pivoting enables the attacker to create an encrypted layer 2 tunnel into the compromised machine to route any network traffic through that target machine, for example to run a vulnerability scan on the internal network through the compromised machine, effectively giving the attacker full network access as if they were behind the firewall.
Typically, the proxy or VPN applications enabling pivoting are executed on the target computer as the payload (software)
Payload (software)
Payload in computing is the cargo of a data transmission. It is the part of the transmitted data which is the fundamental purpose of the transmission, to the exclusion of information sent with it solely to facilitate delivery.In computer security, payload refers to the...
of an exploit.
See also
- Computer insecurityComputer insecurityComputer insecurity refers to the concept that a computer system is always vulnerable to attack, and that this fact creates a constant battle between those looking to improve security, and those looking to circumvent security.-Security and systems design:...
- Computer securityComputer securityComputer security is a branch of computer technology known as information security as applied to computers and networks. The objective of computer security includes protection of information and property from theft, corruption, or natural disaster, while allowing the information and property to...
- Computer virusComputer virusA computer virus is a computer program that can replicate itself and spread from one computer to another. The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability...
- CrimewareCrimewareCrimeware is a class of malware designed specifically to automate cybercrime. The term was coined by Peter Cassidy, Secretary General of the Anti-Phishing Working Group to distinguish it from other kinds of malevolent programs...
- Hacking: The Art of Exploitation Second EditionHacking: The Art of Exploitation Second Edition-Author and background information:This book is written by Jon Erickson and was published in 2008. Jon Erickson is a computer security expert, with a background in computer science. He currently works as a vulnerability researcher and computer security specialist in California. He also wrote...
- IT riskIT riskInformation technology risk, or IT risk, IT-related risk, is a risk related to information technology. This relatively new term due to an increasing awareness that information security is simply one facet of a multitude of risks that are relevant to IT and the real world processes it...
- MetasploitMetasploit ProjectThe Metasploit Project is an open-source computer security project which provides information about security vulnerabilities and aids in penetration testing and IDS signature development....
- ShellcodeShellcodeIn computer security, a shellcode is a small piece of code used as the payload in the exploitation of a software vulnerability. It is called "shellcode" because it typically starts a command shell from which the attacker can control the compromised machine. Shellcode is commonly written in...
- w3afW3afw3af is an open-source web application security scanner. The project provides a vulnerability scanner and exploitation tool for Web applications...