owasp-modsecurity / owasp-modsecurity/ModSecurity
Operator validateurlencoding does not handle IIS url encoding "%uXXXX"
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- Dominant language
- C++
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Description
The operator validateurlencoding does not handle IIS url encoding "%uXXXX" creating false positives with core ruleset 2.2.9 rule id 950107.
The issue is identified on re_operators.c in the function "static int validate_url_encoding(const char *input, long int input_length)" which does not handle IIS url encoding.
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- Read the whole issue, then the project's contributing guide.
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- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in re_operators.c at static int validate_url_encoding(const char *input, long int input_length), then inspect how rule 950107 and core ruleset 2.2.9 use the operator. Reproduce the IIS "%uXXXX" case and verify that the operator handles it without creating the reported false positives.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- security
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100