CAPEC-146

Detailed Abstraction Level
Meta — Very abstract, high-level category
Standard — Specific enough to understand
Detailed — Tied to specific technique Stable MITRE CAPEC Status
Stable — Fully reviewed and complete
Draft — Under development
Incomplete — Partially defined
Deprecated — No longer recommended
Obsolete — Replaced by another CAPEC Likelihood: Low Severity: High
XML Schema Poisoning

Description

An adversary corrupts or modifies the content of XML schema information passed between a client and server for the purpose of undermining the security of the target. XML Schemas provide the structure and content definitions for XML documents. Schema poisoning is the ability to manipulate a schema either by replacing or modifying it to compromise the programs that process documents that use this schema.

Prerequisites

Some level of access to modify the target schema.

The schema used by the target application must be improperly secured against unauthorized modification and manipulation.

Mitigations

Design: Protect the schema against unauthorized modification.

Implementation: For applications that use a known schema, use a local copy or a known good repository instead of the schema reference supplied in the XML document. Additionally, ensure that the proper permissions are set on local files to avoid unauthorized modification.

Implementation: For applications that leverage remote schemas, use the HTTPS protocol to prevent modification of traffic in transit and to avoid unauthorized modification.