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Home > CAPEC List > CAPEC-460: HTTP Parameter Pollution (HPP) (Version 3.5)  

CAPEC-460: HTTP Parameter Pollution (HPP)

Attack Pattern ID: 460
Abstraction: Detailed
Status: Draft
Presentation Filter:
+ Description
An attacker overrides or adds HTTP GET/POST parameters by injecting query string delimiters. Via HPP it may be possible to override existing hardcoded HTTP parameters, modify the application behaviors, access and, potentially exploit, uncontrollable variables, and bypass input validation checkpoints and WAF rules.
+ Typical Severity


+ Relationships
Section HelpThis table shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.
ChildOfStandard Attack PatternStandard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.15Command Delimiters
Section HelpThis table shows the views that this attack pattern belongs to and top level categories within that view.
+ Prerequisites
HTTP protocol is used with some GET/POST parameters passed
+ Resources Required
Any tool that enables intercepting and tampering with HTTP requests
+ Mitigations
Configuration: If using a Web Application Firewall (WAF), filters should be carefully configured to detect abnormal HTTP requests
Design: Perform URL encoding
Implementation: Use strict regular expressions in URL rewriting
Implementation: Beware of multiple occurrences of a parameter in a Query String
+ Taxonomy Mappings
Relevant to the OWASP taxonomy mapping
Entry Name
Web Parameter Tampering
+ References
[REF-397] Luca Carettoni and Stefano di Paola. "HTTP Parameter Pollution". OWASP EU09 Poland. The Open Web Application Security Project (OWASP). 2008. <>.
[REF-606] "OWASP Web Security Testing Guide". Testing for HTTP Parameter Pollution. The Open Web Application Security Project (OWASP). <>.
+ Content History
Submission DateSubmitterOrganization
2014-06-23CAPEC Content TeamThe MITRE Corporation
Modification DateModifierOrganization
2020-12-17CAPEC Content TeamThe MITRE Corporation
Updated Mitigations, References, Taxonomy_Mappings
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Page Last Updated or Reviewed: December 17, 2020