CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

Description

The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.

[object Object]

Common consequences

• Integrity,Access Control→Modify Application Data,Gain Privileges or Assume Identity
  CR and LF characters in an HTTP header may give attackers control of the remaining headers and body of the message that the application intends to send/receive, as well as allowing them to create additional messages entirely under their con

Potential mitigations

• Implementation
  Construct HTTP headers very carefully, avoiding the use of non-validated input data.
• Implementation
  [object Object]
• 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 i
• 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 CWEs

Recent CVEs classified under this CWE