Description
The software receives data from an upstream component, but does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.
Modes of Introduction:
– Implementation
Related Weaknesses
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 response the application intends to send, as well as allowing them to create additional responses entirely under their control.
Potential Mitigations
Phase: Implementation
Description:
Construct HTTP headers very carefully, avoiding the use of non-validated input data.
Phase: Implementation
Description:
Phase: Implementation
Description:
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.
Phase: Implementation
Description:
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.
CVE References
- CVE-2004-2146
- Application accepts CRLF in an object ID, allowing HTTP response splitting.
- CVE-2004-1620
- HTTP response splitting via CRLF in parameter related to URL.
- CVE-2004-1656
- HTTP response splitting via CRLF in parameter related to URL.
- CVE-2005-2060
- Bulletin board allows response splitting via CRLF in parameter.
- CVE-2005-2065
- Bulletin board allows response splitting via CRLF in parameter.
- CVE-2004-2512
- Response splitting via CRLF in PHPSESSID.
- CVE-2005-1951
- Chain: Application accepts CRLF in an object ID, allowing HTTP response splitting.
- CVE-2004-1687
- Chain: HTTP response splitting via CRLF in parameter related to URL.