Scope | Impact | Likelihood |
---|---|---|
Confidentiality Integrity Availability | Read Application Data, Execute Unauthorized Code or Commands |
References | Description |
---|---|
CVE-2002-0738 | XSS using "&={script}". |
Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.
CAPEC-ID | Attack Pattern Name |
---|---|
CAPEC-199 | XSS Using Alternate Syntax An adversary uses alternate forms of keywords or commands that result in the same action as the primary form but which may not be caught by filters. For example, many keywords are processed in a case insensitive manner. If the site's web filtering algorithm does not convert all tags into a consistent case before the comparison with forbidden keywords it is possible to bypass filters (e.g., incomplete black lists) by using an alternate case structure. For example, the "script" tag using the alternate forms of "Script" or "ScRiPt" may bypass filters where "script" is the only form tested. Other variants using different syntax representations are also possible as well as using pollution meta-characters or entities that are eventually ignored by the rendering engine. The attack can result in the execution of otherwise prohibited functionality. |
Name | Organization | Date | Date release | Version |
---|---|---|---|---|
PLOVER | Draft 3 |
Name | Organization | Date | Comment |
---|---|---|---|
Sean Eidemiller | Cigital | added/updated demonstrative examples | |
Eric Dalci | Cigital | updated Time_of_Introduction | |
CWE Content Team | MITRE | updated Name, Relationships, Taxonomy_Mappings | |
CWE Content Team | MITRE | updated Related_Attack_Patterns | |
CWE Content Team | MITRE | updated Demonstrative_Examples, Description, Name, Potential_Mitigations | |
CWE Content Team | MITRE | updated Demonstrative_Examples | |
CWE Content Team | MITRE | updated Potential_Mitigations | |
CWE Content Team | MITRE | updated Common_Consequences | |
CWE Content Team | MITRE | updated Relationships | |
CWE Content Team | MITRE | updated Potential_Mitigations | |
CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings | |
CWE Content Team | MITRE | updated Potential_Mitigations | |
CWE Content Team | MITRE | updated Applicable_Platforms | |
CWE Content Team | MITRE | updated Relationships | |
CWE Content Team | MITRE | updated Potential_Mitigations | |
CWE Content Team | MITRE | updated Demonstrative_Examples | |
CWE Content Team | MITRE | updated Relationships | |
CWE Content Team | MITRE | updated Description | |
CWE Content Team | MITRE | updated Relationships | |
CWE Content Team | MITRE | updated Mapping_Notes |