Incomplete Denylist to Cross-Site Scripting
Draft Compound
Structure: Chain
Description
The product uses a denylist-based protection mechanism to defend against XSS attacks, but the denylist is incomplete, allowing XSS variants to succeed.
While XSS might seem simple to prevent, web browsers vary so widely in how they parse web pages, that a denylist cannot keep track of all the variations. The "XSS Cheat Sheet" [REF-714] contains a large number of attacks that are intended to bypass incomplete denylists.
Common Consequences 1
Scope: ConfidentialityIntegrityAvailability
Impact: Execute Unauthorized Code or Commands
Observed Examples 3
CVE-2007-5727Denylist only removes <SCRIPT> tag.
CVE-2006-3617Denylist only removes <SCRIPT> tag.
CVE-2006-4308Denylist only checks "javascript:" tag
References 1
Applicable Platforms
Languages:
Not Language-Specific : Undetermined
Related Weaknesses