Exploit (computer security): Difference between revisions

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{{Short description|Method of attack on computer systems}}

{{Lead too long|date=August 2024}}

An '''exploit''' is a method or piece of code that takes advantage of [[Vulnerability (computer security)|vulnerabilities]] in [[software]], [[Application software|applications]], [[Computer network|networks]], [[operating systems]], or [[Computer hardware|hardware]], typically for malicious purposes.

The term "exploit" derives from the English verb "to exploit," meaning "to use something to one’s own advantage."

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{{cite web | title = OWASP Secure Coding Practices | website = OWASP Foundation | url = https://owasp.org/www-project-secure-coding-practices-quick-reference-guide/stable-en/03-appendices/05-glossary | access-date = 2024-08-12 | archiveurl = https://web.archive.org/web/20240106035619/https://owasp.org/www-project-secure-coding-practices-quick-reference-guide/stable-en/03-appendices/05-glossary | archivedate = 2024-01-06 | url-status = live | quote = To take advantage of a vulnerability. Typically this is an intentional action designed to compromise the software's security controls by leveraging a vulnerability.}}</ref>

Researchers estimate that malicious exploits cost the [[global economy]] over US$450 billion annually.

In response to this threat, organizations are increasingly utilizing [[cyber threat intelligence]] to identify vulnerabilities and prevent hacks before they occur.<ref>{{Cite journal | last1 = Indiana University, Bloomington | last2 = Samtani | first2 = Sagar | last3 = Chai | first3 = Yidong | last4 = Hefei University of Technology | last5 = Chen | first5 = Hsinchun | last6 = University of Arizona | date = 2022-05-24 | title = Linking Exploits from the Dark Web to Known Vulnerabilities for Proactive Cyber Threat Intelligence: An Attention-Based Deep Structured Semantic Model | url = https://misq.umn.edu/linking-exploits-from-the-dark-web-to-known-vulnerabilities-for-proactive-cyber-threat-intelligence-an-attention-based-deep-structured-semantic-model.html | journal = MIS Quarterly | volume = 46 | issue = 2 | pages = 911–946 | doi = 10.25300/MISQ/2022/15392|url-access=subscription }}</ref>

== Description ==

Exploits target vulnerabilities, which are essentially flaws or weaknesses in a system's defenses.

Common targets for exploits include [[operating systems]], [[web browsers]], and various [[Application software|applications]], where hidden vulnerabilities can compromise the integrity and [[Computer security|security]] of [[computer systems]].

Exploits can cause unintended or unanticipated behavior in systems, potentially leading to severe [[security breaches]].<ref name="MWB-2024-04-15">

{{cite web | title = Exploit Definition | website = Malwarebytes | date = 2024-04-15 | url = https://www.malwarebytes.com/exploits | access-date = 2024-08-12 | archiveurl = https://web.archive.org/web/20240516063544/https://www.malwarebytes.com/exploits | archivedate = 2024-05-16 | url-status = live | quote = A computer exploit is a type of malware that takes advantage of bugs or vulnerabilities, which cybercriminals use to gain illicit access to a system. These vulnerabilities are hidden in the code of the operating system and its applications just waiting to be discovered and put to use by cybercriminals. Commonly exploited software includes the operating system itself, browsers, Microsoft Office, and third-party applications. }}</ref><ref name="mitre-2020-10-15">

{{cite web | title = Obtain Capabilities: Exploits, Sub-technique T1588.005 | website = MITRE ATT&CK® | date = 2020-10-15 | url = https://attack.mitre.org/techniques/T1588/005/ | access-date = 2024-08-12 | archiveurl = https://web.archive.org/web/20240524110426/https://attack.mitre.org/techniques/T1588/005/ | archivedate = 2024-05-24 | url-status = live | quote = Adversaries may buy, steal, or download exploits that can be used during targeting. An exploit takes advantage of a bug or vulnerability in order to cause unintended or unanticipated behavior to occur on computer hardware or software. }}</ref>

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After an exploit is disclosed to the authors of the affected software, the associated vulnerability is often fixed through a [[Patch (computing)|patch]], rendering the exploit unusable.

This is why some [[Black hat (computer security)|black hat hackers]], as well as military or intelligence agency hackers, do not publish their exploits but keep them private.

One scheme that offers zero-day exploits is known as [[exploit as a service]].<ref name=EAA_1>{{cite web| title=Exploit-as-a-service: Cybercriminals exploring potential of leasing out zero-day vulnerabilities| author=Leyden, J.| work=The Daily Swig &#124; Cybersecurity news and views| url=https://portswigger.net/daily-swig/exploit-as-a-service-cybercriminals-exploring-potential-of-leasing-out-zero-day-vulnerabilities| publisher=PortSwigger Ltd| date=16 November 2021| access-date=18 December 2023}}</ref>

Researchers estimate that malicious exploits cost the [[global economy]] over US$450 billion annually.

In response to this threat, organizations are increasingly utilizing [[cyber threat intelligence]] to identify vulnerabilities and prevent hacks before they occur.<ref>{{Cite journal | last1 = Indiana University, Bloomington | last2 = Samtani | first2 = Sagar | last3 = Chai | first3 = Yidong | last4 = Hefei University of Technology | last5 = Chen | first5 = Hsinchun | last6 = University of Arizona | date = 2022-05-24 | title = Linking Exploits from the Dark Web to Known Vulnerabilities for Proactive Cyber Threat Intelligence: An Attention-Based Deep Structured Semantic Model | url = https://misq.umn.edu/linking-exploits-from-the-dark-web-to-known-vulnerabilities-for-proactive-cyber-threat-intelligence-an-attention-based-deep-structured-semantic-model.html | journal = MIS Quarterly | volume = 46 | issue = 2 | pages = 911–946 | doi = 10.25300/MISQ/2022/15392}}</ref>

==Classification==

There are several methods of classifying exploits. The most common is by how the exploit communicates to the vulnerable software.

''By Method of Communication:''<ref name=":0">{{Cite web |date=2024-06-18 |title=What Is An Exploit? |url=https://www.ituonline.com/tech-definitions/what-is-an-exploit/ |access-date=2025-03-15 |language=en-US}}</ref>

A ''remote exploit'' works over a network and exploits the security vulnerability without any prior access to the vulnerable system.

A* ''remote'Remote exploitExploits''': worksWorks over a network and exploits the security vulnerability without any prior access to the vulnerable system.

A ''local exploit'' requires prior access or physical access to the vulnerable system, and usually increases the privileges of the person running the exploit past those granted by the system administrator. Exploits against client applications also exist, usually consisting of modified servers that send an exploit if accessed with a client application. A common form of exploits against client applications are [[browser exploit]]s. Exploits against client applications may also require some interaction with the user and thus may be used in combination with the [[social engineering (security)|social engineering]] method.

* '''Local Exploits:''' Requires prior access or physical access to the vulnerable system, and usually increases the privileges of the person running the exploit past those granted by the system administrator.

''By Targeted Component:''<ref name=":0" />

* '''Server-Side Exploits''': Target vulnerabilities in server applications, such as web servers or database servers, often by sending maliciously crafted requests to exploit security flaws.

* '''Client-Side Exploits''': Target vulnerabilities in client applications, such as web browsers ([[browser exploit]]s) or media players. These exploits often require user interaction, like visiting a malicious website or opening a compromised file. Exploits against client applications may also require some interaction with the user and thus may be used in combination with the [[social engineering (security)|social engineering]] method.

The classification of exploits based<ref>{{cite web |title=Exploits Database by Offensive Security |url=https://www.exploit-db.com/ |website=www.exploit-db.com}}</ref><ref>{{cite web |title=Exploit Database {{!}} Rapid7 |url=https://www.rapid7.com/db/modules/ |website=www.rapid7.com}}</ref> on the type of vulnerability they exploit and the result of running the exploit (e.g., Elevation of Privilege ([[Elevation of Privilege (computing)|EoP]]), Denial of Service ([[Denial of Service (computing)|DoS]]), [[Spoofing attack|spoofing]]) is a common practice in cybersecurity. This approach helps in systematically identifying and addressing security threats. For instance, the STRIDE threat model categorizes threats into six types, including Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege.<ref>{{Cite web |title=What Is the STRIDE Threat Model? |url=https://www.purestorage.com/knowledge/stride-threat-model.html |access-date=2025-03-15 |website=www.purestorage.com |language=en-US}}</ref> Similarly, the National Vulnerability Database (NVD) categorizes vulnerabilities by types such as Authentication Bypass by Spoofing and Authorization Bypass.<ref>{{Cite web |title=National Vulnerability Database - Vulnerabilities |url=https://nvd.nist.gov/vuln/categories |access-date=2025-03-15 |website=nvd.nist.gov}}</ref>

''By Type of [[Vulnerability (computer security)|Vulnerability]]:''

* '''Code Execution Exploits:''' Allow attackers to execute arbitrary code on the target system, potentially leading to full system compromise.

* '''Denial-of-Service (DoS) Exploits''': Aim to disrupt the normal functioning of a system or service, making it unavailable to legitimate users.

* '''Privilege Escalation Exploits''': Enable attackers to gain higher privileges on a system than initially granted, potentially leading to unauthorized actions.

* '''Information Disclosure Exploits:''' Lead to unauthorized access to sensitive information due to vulnerabilities in the system.

Another classification is by the action against the vulnerable system; unauthorized data access, arbitrary code execution, and denial of service are examples.

== Exploitation Techniques ==

Exploitations are commonly categorized and named<ref>{{cite web|title=Exploits Database by Offensive Security|url=https://www.exploit-db.com/|website=www.exploit-db.com}}</ref><ref>{{cite web|title=Exploit Database {{!}} Rapid7|url=https://www.rapid7.com/db/modules/|website=www.rapid7.com}}</ref> by the type of vulnerability they exploit {{Clarify | text = (see [[Vulnerability (computing)|vulnerabilities]] for a list)| date = August 2024 | reason = This should link to the section where there is supposed to be a 'list.' Which list this is talking about isn't obvious.}}, whether they are local/remote and the result of running the exploit (e.g. [[Elevation of Privilege (computing)|EoP]], [[Denial of Service (computing)|DoS]], [[Spoofing attack|spoofing]]).

Attackers employ various techniques to exploit vulnerabilities and achieve their objectives. Some common methods include:<ref name=":0" />

* '''[[Buffer overflow|Buffer Overflow]]:''' Attackers send more data to a buffer than it can handle, causing it to overflow and overwrite adjacent memory, potentially allowing arbitrary code execution.

* '''SQL Injection:''' Malicious [[SQL]] code is inserted into input fields of web applications, enabling attackers to access or manipulate databases.

* '''Cross-Site Scripting (XSS):''' Attackers inject malicious scripts into web pages viewed by other users, potentially leading to session hijacking or data theft.

* '''Cross-Site Request Forgery (CSRF):''' Attackers trick users into performing actions they did not intend, such as changing account settings, by exploiting the user's authenticated session.

=== Zero-click ===

A zero-click attack is an exploit that requires no [[user interaction]] to operate – that is to say, no key-presses or mouse clicks.<ref>{{Cite magazine|title=Sneaky Zero-Click Attacks Are a Hidden Menace|language=en-US|magazine=Wired|url=https://www.wired.com/story/sneaky-zero-click-attacks-hidden-menace/|access-date=2021-09-14|issn=1059-1028}}</ref> [[FORCEDENTRY]],These discoveredexploits inare 2021,commonly isthe anmost examplesought ofafter aexploits zero-click(specifically attack.<ref>{{Citeon magazine|title=Thethe Stealthyunderground iPhoneexploit Hacksmarket) Thatbecause Applethe Stilltarget Can'ttypically Stop|language=en-US|magazine=Wired|url=https://www.wired.com/story/apple-imessage-zero-click-hacks/|access-date=2021-09-14|issn=1059-1028}}</ref><ref>{{Citehas web|title=Ano newway NSOof zero-clickknowing attackthey evadeshave Apple'sbeen iPhonecompromised securityat protections,the saystime Citizenof Lab|url=https://techcrunchexploitation.com/2021/08/24/nso-pegasus-bahrain-iphone-security/|access-date=2021-09-14|website=TechCrunch|date=24 August 2021|language=en-US|archive-date=2021-08-24|archive-url=https://web.archive.org/web/20210824124718/https://social.techcrunch.com/2021/08/24/nso-pegasus-bahrain-iphone-security/|url-status=live}}</ref>

[[FORCEDENTRY]], discovered in 2021, is an example of a zero-click attack.<ref>{{Cite magazine|title=The Stealthy iPhone Hacks That Apple Still Can't Stop|magazine=Wired|url=https://www.wired.com/story/apple-imessage-zero-click-hacks/|access-date=2021-09-14|issn=1059-1028}}</ref><ref>{{cite web |last=Whittaker |first=Zack |title=A new NSO zero-click attack evades Apple's iPhone security protections, says Citizen Lab |url=https://techcrunch.com/2021/08/24/nso-pegasus-bahrain-iphone-security/ |access-date=2025-05-25 |work=[[TechCrunch]] |date=24 August 2021 |archive-date=2021-08-24 |archive-url=https://web.archive.org/web/20210824103937/https://techcrunch.com/2021/08/24/nso-pegasus-bahrain-iphone-security/ |url-status=live}}</ref>

These exploits are commonly the most sought after exploits (specifically on the underground exploit market) because the target typically has no way of knowing they have been compromised at the time of exploitation.

In 2022, [[NSO Group]] was reportedly selling zero-click exploits to governments for breaking into individuals' phones.<ref>{{cite news |journal=Insurance Journal |url=https://www.insurancejournal.com/news/international/2022/02/18/654917.htm |title=Beware of 'Zero-Click' Hacks That Exploit Security Flaws in Phones' Operating Systems |author=Ryan Gallagher |date=February 18, 2022}}</ref>

For mobile devices, the [[National Security Agency]] (NSA) points out that timely updating of software and applications, avoiding public network connections, and turnturning the device Off and On at least once a week can mitigate the threat of zero-click attacks. <ref>{{Cite web |title=Why you should power off your phone once a week - according to the NSA |url=https://www.zdnet.com/article/why-you-should-power-off-your-phone-once-a-week-according-to-the-nsa/ |access-date=2025-03-01 |website=ZDNET |language=en}}</ref><ref>{{Cite web |title=Telework and Mobile Security Guidance |url=https://www.nsa.gov/Press-Room/Telework-and-Mobile-Security-Guidance/ |access-date=2025-03-01 |website=www.nsa.gov}}</ref><ref>{{Cite web |last=Winder |first=Davey |title=NSA Warns iPhone And Android Users To Turn It Off And On Again |url=https://www.forbes.com/sites/daveywinder/2024/06/01/nsa-warns-iphone--android-users-to-turn-it-off-and-on-again/ |access-date=2025-03-01 |website=Forbes |language=en}}</ref> Experts say that protection practices for traditional endpoints are also applicable to mobile devices;. manyMany exploits exist only in [[Computer memory|memory]], not in files. Theoretically, restarting the device can wipe malware payloads from memory, forcing attackers back to the beginning of the attackexploit chain. <ref name="zdnet25021801">{{Cite web |title=Why rebooting your phone daily is your best defense against zero-click attacks |url=https://www.zdnet.com/article/why-rebooting-your-phone-daily-is-your-best-defense-against-zero-click-attacks/ |access-date=2025-03-01 |website=ZDNET |language=en}}</ref><ref>{{Cite web |last=Taylor |first=Craig |date=2020-01-10 |title=Exploit Chain - CyberHoot Cyber Library |url=https://cyberhoot.com/cybrary/exploit-chain/ |access-date=2025-03-01 |website=CyberHoot |language=en-US}}</ref>

=== Pivoting ===

{{Off topic|date=August 2024|Pivoting (computer security)|Pivoting is a follow-on to an exploit}}

Pivoting is a technique employed by both hackers and [[penetration test]]ers to expand their access within a target network. By compromising a system, attackers can leverage it as a platform to target other systems that are typically shielded from direct external access by [[Firewall (computing)|firewalls]]. Internal networks often contain a broader range of accessible machines compared to those exposed to the internet. For example, an attacker might compromise a web server on a corporate network and then utilize it to target other systems within the same network. This approach is often referred to as a multi-layered attack. Pivoting is also known as ''island hopping''.