Security: Potential Regular Expression Denial of Service (ReDoS)#2095
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Multiple recognizers use complex regular expressions that could be vulnerable to ReDoS attacks if an attacker can provide crafted input. The EmailRecognizer in particular has a complex regex pattern that could exhibit catastrophic backtracking. Affected files: email_recognizer.py Signed-off-by: tuanaiseo <221258316+tuanaiseo@users.noreply.github.com>
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Pull request overview
This PR addresses a potential Regular Expression Denial of Service (ReDoS) risk in Presidio Analyzer’s EmailRecognizer by simplifying the email detection regex used by the generic predefined recognizers.
Changes:
- Replaced the previous complex email-matching regex with a simpler, more ReDoS-resistant pattern.
- Kept the recognizer structure and
tldextract-basedvalidate_result()behavior unchanged.
| Pattern( | ||
| "Email (Medium)", | ||
| r"\b((([!#$%&'*+\-/=?^_`{|}~\w])|([!#$%&'*+\-/=?^_`{|}~\w][!#$%&'*+\-/=?^_`{|}~\.\w]{0,}[!#$%&'*+\-/=?^_`{|}~\w]))[@]\w+([-.]\w+)*\.\w+([-.]\w+)*)\b", | ||
| r"\b[A-Za-z0-9!#$%&'*+\-/=?^_`{|}~]+@[A-Za-z0-9]+([-.][A-Za-z0-9]+)*\.[A-Za-z]{2,}\b", |
| Pattern( | ||
| "Email (Medium)", | ||
| r"\b((([!#$%&'*+\-/=?^_`{|}~\w])|([!#$%&'*+\-/=?^_`{|}~\w][!#$%&'*+\-/=?^_`{|}~\.\w]{0,}[!#$%&'*+\-/=?^_`{|}~\w]))[@]\w+([-.]\w+)*\.\w+([-.]\w+)*)\b", | ||
| r"\b[A-Za-z0-9!#$%&'*+\-/=?^_`{|}~]+@[A-Za-z0-9]+([-.][A-Za-z0-9]+)*\.[A-Za-z]{2,}\b", |
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Problem
Multiple recognizers use complex regular expressions that could be vulnerable to ReDoS attacks if an attacker can provide crafted input. The EmailRecognizer in particular has a complex regex pattern that could exhibit catastrophic backtracking.
Severity:
mediumFile:
presidio-analyzer/presidio_analyzer/predefined_recognizers/generic/email_recognizer.pySolution
Review and optimize regex patterns to prevent catastrophic backtracking. Consider using a regex timeout or implementing pattern complexity limits. Use more specific character classes and avoid nested quantifiers where possible.
Changes
presidio-analyzer/presidio_analyzer/predefined_recognizers/generic/email_recognizer.py(modified)Testing