CWE-625: Permissive Regular Expression
The product uses a regular expression that does not sufficiently restrict the set of allowed values.
How it's found
Permissive Regular Expression is typically found by tracing untrusted input from where it enters the system to the point where it is used without the check or neutralization this weakness describes, combining manual code review with dynamic testing.
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
Consequences
- Bypass Protection Mechanism
Mitigations
- Implementation: When applicable, ensure that the regular expression marks beginning and ending string patterns, such as "/^string$/" for Perl.
Where this fits in a TurboPentest engagement
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Frequently asked questions
What is CWE-625?
The product uses a regular expression that does not sufficiently restrict the set of allowed values.
How do you find Permissive Regular Expression?
Permissive Regular Expression is typically found by tracing untrusted input from where it enters the system to the point where it is used without the check or neutralization this weakness describes, combining manual code review with dynamic testing.
What is the impact of CWE-625?
Bypass Protection Mechanism
Does TurboPentest test for Permissive Regular Expression?
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Related CWEs
Written and reviewed by
Michel Chamberland - Founder & CEO, IntegSec
CISSP, OSCP, OSCE, CEH, GIAC, CCSK · 20+ years in offensive security
Michel has spent 20+ years on offensive security teams including IBM X-Force Red and Trustwave SpiderLabs, leading penetration tests, red team engagements, and breach response for Fortune 500 customers. He is the founder of IntegSec and the architect of TurboPentest.
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