LDAP Injection Pattern Regex for PHP

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching ldap injection pattern, ported and verified for PHP. In security-sensitive code, using an unverified regex can open the door to both false positives and denial-of-service attacks. The snippet below is ready to drop into your PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

<?php
// LDAP Injection Pattern
// ReDoS-safe | RegexVault — Security > Injection Patterns

define('LDAP_INJECTION_PATTERN_PATTERN', '/[)(|*\\\x00]|(?:objectclass|objectCategory|objectGUID|samAccountName|userPrincipalName|memberOf)\s*=|(?:\(uid=)|(?:cn=)(?:[^,)]*\*)/');

function validate_ldap_injection_pattern(string $input): bool {
    return (bool) preg_match(LDAP_INJECTION_PATTERN_PATTERN, $input);
}

// Example
var_dump(validate_ldap_injection_pattern("*)(uid=*))(|(uid=*")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Security > Injection Patterns category and carries a ReDoS-safe certification. That matters for PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

LDAP special characters: ( ) * \ and null byte. Classic injection: *(|(mail=*)) returns all records when injected into a filter. Defense: use LDAP parameter encoding to escape special characters in search filters. RFC 4515 defines the escape sequences.