Weakness · High
CWE-625: Permissive Regular Expression
What it is
The product uses a regular expression that does not sufficiently restrict the set of allowed values.
- Severity (our rating)
- High
- Likelihood of exploit
- Not rated by MITRE
- Introduced during
- Implementation
- Exploited in the wild
- No CVE in CISA's catalog
In more detail
This effectively causes the regexp to accept substrings that match the pattern, which produces a partial comparison to the target. In some cases, this can lead to other weaknesses. Common errors include: not identifying the beginning and end of the target string using wildcards instead of acceptable character ranges others
What an attacker can do
- Bypass Protection Mechanism (Access Control)
How to prevent it
Implementation
- When applicable, ensure that the regular expression marks beginning and ending string patterns, such as "/^string$/" for Perl.
How to find it
- 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.)
H2 Security
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Start freeSource: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.