CWE-93: Improper Neutralization of CRLF Sequences ('CRLF… | Glexia
CWE-93 (Improper Neutralization of CRLF Sequences ('CRLF Injection')) weakness overview with consequences, detection methods, mitigations, related CVEs and MITRE…
Glexia's Take · Automated analysis
CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')
Improper Neutralization of CRLF Sequences ('CRLF Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Integrity: Modify Application Data
Developer Pattern
CWE-93 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Automation confidence
high confidence from CWE-93, 4.20.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Official CWE Definition
CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- If user input data that eventually makes it to a log message isn't checked for CRLF characters, it may be possible for an attacker to forge entries in a log file.
Remediation
- Implementation: Avoid using CRLF as a special sequence.
- Implementation: Appropriately filter or quote CRLF sequences in user-controlled input.
Detection
- Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
- CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
- CWE-144: Improper Neutralization of Line Delimiters
- CWE-145: Improper Neutralization of Section Delimiters
- CWE-117: Improper Output Neutralization for Logs
- CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.