Regular Expression Security Cheatsheet

Regular Expression Security Cheatsheet

Introduction

This cheatsheet can be effectively used by security specialists and programmers to reveal unwanted constructions in regular expressions, which can cause bypass of their rules.
Despite original work was focused on finding "weak places" in regular expressions of Intrusion Detection Systems (WAFs), it can be effectively applied to any other code.

Cheatsheet

Due to the fact, that OWASP's MediaWiki styling could not compete to Markdown, I decided not to include full table here, but provide a link to GitHub repository instead:

SAST

In order to save time for security practitioners, Static Application Security Testing tool was written. You can use the following code to analyse all regular expressions from your PHP project:
grep -iorP "reg_\w+\s*\((\s*['\"](.*?)['\"])," * > regexp.txt && php index.php --file="./regexp.txt"

SAST can be downloaded from here:

Authors and Primary Editors

Vladimir Ivanov
@httpsonly