Detalle CWE-79

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Alto
Stable
2006-07-19
00h00 +00:00
2025-12-11
00h00 +00:00
CWE Mitre.org
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Nombre: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Informaciones generales

Detalles de contexto

Modos de introducción

Implementation : REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Plataformas aplicables

Lenguaje

Class: Not Language-Specific (Undetermined)

Tecnologías

Name: AI/ML (Undetermined)
Class: Web Based (Often)
Name: Web Server (Undetermined)

Consecuencias comunes

Alcance Impacto Probabilidad
Access Control
Confidentiality		Bypass Protection Mechanism, Read Application Data

Note: The most common attack performed with cross-site scripting involves the disclosure of private information stored in user cookies, such as session information. Typically, a malicious user will craft a client-side script, which -- when parsed by a web browser -- performs some activity on behalf of the victim to an attacker-controlled system (such as sending all site cookies to a given E-mail address). This could be especially dangerous to the site if the victim has administrator privileges to manage that site. This script will be loaded and run by each user visiting the web site. Since the site requesting to run the script has access to the cookies in question, the malicious script does also.
Integrity
Confidentiality
Availability		Execute Unauthorized Code or Commands

Note: In some circumstances it may be possible to run arbitrary code on a victim's computer when cross-site scripting is combined with other flaws, for example, "drive-by hacking."
Confidentiality
Integrity
Availability
Access Control		Execute Unauthorized Code or Commands, Bypass Protection Mechanism, Read Application Data

Note: The consequence of an XSS attack is the same regardless of whether it is stored or reflected. The difference is in how the payload arrives at the server. XSS can cause a variety of problems for the end user that range in severity from an annoyance to complete account compromise. Some cross-site scripting vulnerabilities can be exploited to manipulate or steal cookies, create requests that can be mistaken for those of a valid user, compromise confidential information, or execute malicious code on the end user systems for a variety of nefarious purposes. Other damaging attacks include the disclosure of end user files, installation of Trojan horse programs, redirecting the user to some other page or site, running "Active X" controls (under Microsoft Internet Explorer) from sites that a user perceives as trustworthy, and modifying presentation of content.

Ejemplos observados

Referencias Descripción

CVE-2024-49038

XSS in AI assistant

CVE-2024-54142

Plugin that enables AI features allows input with html entities, leading to XSS

CVE-2021-25926

Python Library Manager did not sufficiently neutralize a user-supplied search term, allowing reflected XSS.

CVE-2021-25963

Python-based e-commerce platform did not escape returned content on error pages, allowing for reflected Cross-Site Scripting attacks.

CVE-2021-1879

Universal XSS in mobile operating system, as exploited in the wild per CISA KEV.

CVE-2020-3580

Chain: improper input validation (CWE-20) in firewall product leads to XSS (CWE-79), as exploited in the wild per CISA KEV.

CVE-2014-8958

Admin GUI allows XSS through cookie.

CVE-2017-9764

Web stats program allows XSS through crafted HTTP header.

CVE-2014-5198

Web log analysis product allows XSS through crafted HTTP Referer header.

CVE-2008-5080

Chain: protection mechanism failure allows XSS

CVE-2006-4308

Chain: incomplete denylist (CWE-184) only checks "javascript:" tag, allowing XSS (CWE-79) using other tags

CVE-2007-5727

Chain: incomplete denylist (CWE-184) only removes SCRIPT tags, enabling XSS (CWE-79)

CVE-2008-5770

Reflected XSS using the PATH_INFO in a URL

CVE-2008-4730

Reflected XSS not properly handled when generating an error message

CVE-2008-5734

Reflected XSS sent through email message.

CVE-2008-0971

Stored XSS in a security product.

CVE-2008-5249

Stored XSS using a wiki page.

CVE-2006-3568

Stored XSS in a guestbook application.

CVE-2006-3211

Stored XSS in a guestbook application using a javascript: URI in a bbcode img tag.

CVE-2006-3295

Chain: library file is not protected against a direct request (CWE-425), leading to reflected XSS (CWE-79).

Mitigaciones potenciales

Phases : Architecture and Design
Phases : Implementation // Architecture and Design
Phases : Architecture and Design // Implementation
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
Phases : Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Phases : Architecture and Design
If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.
Phases : Implementation
Phases : Implementation
With Struts, write all data from form beans with the bean's filter attribute set to true.
Phases : Implementation
To help mitigate XSS attacks against the user's session cookie, set the session cookie to be HttpOnly. In browsers that support the HttpOnly feature (such as more recent versions of Internet Explorer and Firefox), this attribute can prevent the user's session cookie from being accessible to malicious client-side scripts that use document.cookie. This is not a complete solution, since HttpOnly is not supported by all browsers. More importantly, XMLHTTPRequest and other powerful browser technologies provide read access to HTTP headers, including the Set-Cookie header in which the HttpOnly flag is set.
Phases : Implementation
Phases : Architecture and Design
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
Phases : Operation
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
Phases : Operation // Implementation
When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

Métodos de detección

Automated Static Analysis

Use automated static analysis tools that target this type of weakness. Many modern techniques use data flow analysis to minimize the number of false positives. This is not a perfect solution, since 100% accuracy and coverage are not feasible, especially when multiple components are involved.
Efectividad : Moderate

Black Box

Use the XSS Cheat Sheet [REF-714] or automated test-generation tools to help launch a wide variety of attacks against your web application. The Cheat Sheet contains many subtle XSS variations that are specifically targeted against weak XSS defenses.
Efectividad : Moderate

Notas de mapeo de vulnerabilidades

Justificación : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comentario : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Patrones de ataque relacionados

CAPEC-ID Nombre del patrón de ataque
CAPEC-209 XSS Using MIME Type Mismatch
An adversary creates a file with scripting content but where the specified MIME type of the file is such that scripting is not expected. The adversary tricks the victim into accessing a URL that responds with the script file. Some browsers will detect that the specified MIME type of the file does not match the actual type of its content and will automatically switch to using an interpreter for the real content type. If the browser does not invoke script filters before doing this, the adversary's script may run on the target unsanitized, possibly revealing the victim's cookies or executing arbitrary script in their browser.
CAPEC-588 DOM-Based XSS
This type of attack is a form of Cross-Site Scripting (XSS) where a malicious script is inserted into the client-side HTML being parsed by a web browser. Content served by a vulnerable web application includes script code used to manipulate the Document Object Model (DOM). This script code either does not properly validate input, or does not perform proper output encoding, thus creating an opportunity for an adversary to inject a malicious script launch a XSS attack. A key distinction between other XSS attacks and DOM-based attacks is that in other XSS attacks, the malicious script runs when the vulnerable web page is initially loaded, while a DOM-based attack executes sometime after the page loads. Another distinction of DOM-based attacks is that in some cases, the malicious script is never sent to the vulnerable web server at all. An attack like this is guaranteed to bypass any server-side filtering attempts to protect users.
CAPEC-591 Reflected XSS
This type of attack is a form of Cross-Site Scripting (XSS) where a malicious script is "reflected" off a vulnerable web application and then executed by a victim's browser. The process starts with an adversary delivering a malicious script to a victim and convincing the victim to send the script to the vulnerable web application.
CAPEC-592 Stored XSS
An adversary utilizes a form of Cross-site Scripting (XSS) where a malicious script is persistently "stored" within the data storage of a vulnerable web application as valid input.
CAPEC-63 Cross-Site Scripting (XSS)
An adversary embeds malicious scripts in content that will be served to web browsers. The goal of the attack is for the target software, the client-side browser, to execute the script with the users' privilege level. An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute code and scripts. Web browsers, for example, have some simple security controls in place, but if a remote attacker is allowed to execute scripts (through injecting them in to user-generated content like bulletin boards) then these controls may be bypassed. Further, these attacks are very difficult for an end user to detect.
CAPEC-85 AJAX Footprinting
This attack utilizes the frequent client-server roundtrips in Ajax conversation to scan a system. While Ajax does not open up new vulnerabilities per se, it does optimize them from an attacker point of view. A common first step for an attacker is to footprint the target environment to understand what attacks will work. Since footprinting relies on enumeration, the conversational pattern of rapid, multiple requests and responses that are typical in Ajax applications enable an attacker to look for many vulnerabilities, well-known ports, network locations and so on. The knowledge gained through Ajax fingerprinting can be used to support other attacks, such as XSS.

Notas






Referencias

REF-709

XSS Attacks
Jeremiah Grossman, Robert "RSnake" Hansen, Petko "pdp" D. Petkov, Anton Rager, Seth Fogie.

REF-44

24 Deadly Sins of Software Security
Michael Howard, David LeBlanc, John Viega.

REF-44

24 Deadly Sins of Software Security
Michael Howard, David LeBlanc, John Viega.

REF-712

Cross-site scripting
https://en.wikipedia.org/wiki/Cross-site_scripting

REF-7

Writing Secure Code
Michael Howard, David LeBlanc.
https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223

REF-714

XSS (Cross Site Scripting) Cheat Sheet
RSnake.
http://ha.ckers.org/xss.html

REF-715

Mitigating Cross-site Scripting With HTTP-only Cookies
Microsoft.
https://learn.microsoft.com/en-us/previous-versions//ms533046(v=vs.85)?redirectedfrom=MSDN

REF-716

Anti-XSS 3.0 Beta and CAT.NET Community Technology Preview now Live!
Mark Curphey, Microsoft.
https://learn.microsoft.com/en-us/archive/blogs/cisg/anti-xss-3-0-beta-and-cat-net-community-technology-preview-now-live

REF-45

OWASP Enterprise Security API (ESAPI) Project
OWASP.
https://owasp.org/www-project-enterprise-security-api/

REF-718

XSS Defense HOWTO
Ivan Ristic.
https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/xss-defense-howto/

REF-719

Web Application Firewall
OWASP.
http://www.owasp.org/index.php/Web_Application_Firewall

REF-720

Web Application Firewall Evaluation Criteria
Web Application Security Consortium.
http://projects.webappsec.org/w/page/13246985/Web%20Application%20Firewall%20Evaluation%20Criteria

REF-721

Firefox Implements httpOnly And is Vulnerable to XMLHTTPRequest
RSnake.

REF-722

XMLHttpRequest allows reading HTTPOnly cookies
https://bugzilla.mozilla.org/show_bug.cgi?id=380418

REF-723

Apache Wicket
http://wicket.apache.org/

REF-724

XSS (Cross Site Scripting) Prevention Cheat Sheet
OWASP.
http://www.owasp.org/index.php/XSS_(Cross_Site_Scripting)_Prevention_Cheat_Sheet

REF-725

DOM based XSS Prevention Cheat Sheet
OWASP.
http://www.owasp.org/index.php/DOM_based_XSS_Prevention_Cheat_Sheet

REF-726

Top 25 series - Rank 1 - Cross Site Scripting
Jason Lam.
https://www.sans.org/blog/top-25-series-rank-1-cross-site-scripting/

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

REF-956

Samy (computer worm)
Wikipedia.
https://en.wikipedia.org/wiki/Samy_(computer_worm)

REF-962

Automated Source Code Security Measure (ASCSM)
Object Management Group (OMG).
http://www.omg.org/spec/ASCSM/1.0/

REF-1481

D3FEND: Application Layer Firewall
D3FEND.
https://d3fend.mitre.org/dao/artifact/d3f:ApplicationLayerFirewall/

REF-1482

D3FEND: D3-TL Trusted Library
D3FEND.
https://d3fend.mitre.org/technique/d3f:TrustedLibrary/

Envío

Nombre Organización Fecha Fecha de lanzamiento Version
PLOVER 2006-07-19 +00:00 2006-07-19 +00:00 Draft 3

Modificaciones

Nombre Organización Fecha Comentario
Eric Dalci Cigital 2008-07-01 +00:00 updated Time_of_Introduction
Veracode 2008-08-15 +00:00 Suggested OWASP Top Ten 2004 mapping
CWE Content Team MITRE 2008-09-08 +00:00 updated Alternate_Terms, Applicable_Platforms, Background_Details, Common_Consequences, Description, Relationships, Other_Notes, References, Taxonomy_Mappings, Weakness_Ordinalities
CWE Content Team MITRE 2009-01-12 +00:00 updated Alternate_Terms, Applicable_Platforms, Background_Details, Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Enabling_Factors_for_Exploitation, Name, Observed_Examples, Other_Notes, Potential_Mitigations, References, Relationships
CWE Content Team MITRE 2009-03-10 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2009-05-27 +00:00 updated Name
CWE Content Team MITRE 2009-07-27 +00:00 updated Description
CWE Content Team MITRE 2009-10-29 +00:00 updated Observed_Examples, Relationships
CWE Content Team MITRE 2009-12-28 +00:00 updated Demonstrative_Examples, Description, Detection_Factors, Enabling_Factors_for_Exploitation, Observed_Examples
CWE Content Team MITRE 2010-02-16 +00:00 updated Applicable_Platforms, Detection_Factors, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2010-04-05 +00:00 updated Description, Potential_Mitigations, Related_Attack_Patterns
CWE Content Team MITRE 2010-06-21 +00:00 updated Common_Consequences, Description, Name, Potential_Mitigations, References, Relationships
CWE Content Team MITRE 2010-09-27 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2011-03-29 +00:00 updated Demonstrative_Examples, References
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2011-06-27 +00:00 updated Relationships
CWE Content Team MITRE 2011-09-13 +00:00 updated Detection_Factors, Potential_Mitigations
CWE Content Team MITRE 2012-05-11 +00:00 updated References, Relationships
CWE Content Team MITRE 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2013-07-17 +00:00 updated Relationships
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2015-12-07 +00:00 updated Relationships
CWE Content Team MITRE 2017-01-19 +00:00 updated Related_Attack_Patterns
CWE Content Team MITRE 2017-05-03 +00:00 updated Related_Attack_Patterns, Relationships
CWE Content Team MITRE 2017-11-08 +00:00 updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples, Enabling_Factors_for_Exploitation, Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships
CWE Content Team MITRE 2018-03-27 +00:00 updated Alternate_Terms, Demonstrative_Examples, Description, Observed_Examples, References, Relationship_Notes, Relationships
CWE Content Team MITRE 2019-01-03 +00:00 updated References, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2019-09-19 +00:00 updated Relationships
CWE Content Team MITRE 2020-02-24 +00:00 updated Applicable_Platforms, Potential_Mitigations, Relationships
CWE Content Team MITRE 2020-06-25 +00:00 updated Observed_Examples, Potential_Mitigations
CWE Content Team MITRE 2020-08-20 +00:00 updated Relationships
CWE Content Team MITRE 2020-12-10 +00:00 updated Relationships
CWE Content Team MITRE 2021-03-15 +00:00 updated Demonstrative_Examples, Description
CWE Content Team MITRE 2021-07-20 +00:00 updated Relationships
CWE Content Team MITRE 2021-10-28 +00:00 updated Relationships
CWE Content Team MITRE 2022-06-28 +00:00 updated Observed_Examples, Relationships
CWE Content Team MITRE 2022-10-13 +00:00 updated Background_Details, Observed_Examples
CWE Content Team MITRE 2023-01-31 +00:00 updated Alternate_Terms, Demonstrative_Examples, Description
CWE Content Team MITRE 2023-04-27 +00:00 updated References, Relationships, Time_of_Introduction
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes, Relationships
CWE Content Team MITRE 2024-02-29 +00:00 updated Relationships
CWE Content Team MITRE 2024-11-19 +00:00 updated Relationships
CWE Content Team MITRE 2025-04-03 +00:00 updated Alternate_Terms, Common_Consequences, Description, Diagram, Other_Notes
CWE Content Team MITRE 2025-09-09 +00:00 updated Applicable_Platforms, Observed_Examples, Potential_Mitigations, References
CWE Content Team MITRE 2025-12-11 +00:00 updated Applicable_Platforms, Demonstrative_Examples, Relationships
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