CWE-173Improper Handling of Alternate Encoding

Description

Common consequences· 1

• Access Control — Bypass Protection Mechanism

Potential mitigations· 4

• [Architecture and Design]Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
• [Implementation]
• [Implementation]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.
• [Implementation]Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.

Related CAPEC attack patterns· 12

Exploits (incoming)12

Related by meaning· 6

Nearest entities by semantic similarity across the cs-graph corpus.