GHSA-gcp9-5jc8-976x phpMyFAQ has a LIKE Wildcard Injection in Search.php — Unescaped % and _ Metacharacters Enable Broad Content Disclosure

• Packagist thorsten/phpmyfaq: < 4.1.1 → fixed in 4.1.1

Summary The `searchCustomPages()` method in `phpmyfaq/src/phpMyFAQ/Search.php` uses `real_escape_string()` (via `escape()`) to sanitize the search term before embedding it in LIKE clauses. However, `real_escape_string()` does not escape SQL LIKE metacharacters `%` (match any sequence) and `_` (match any single character). An unauthenticated attacker can inject these wildcards into search queries, causing them to match unintended records — including content that was not meant to be surfaced — resulting in information disclosure. Details File: `phpmyfaq/src/phpMyFAQ/Search.php`, lines 226–240 Vulnerable code: ```php $escapedSearchTerm = $this->configuration->getDb()->escape($searchTerm); $searchWords = explode(' ', $escapedSearchTerm); $searchConditions = []; foreach ($searchWords as $word) { if (strlen($word) <= 2) { continue; } $searchConditions[] = sprintf( "(page_title LIKE '%%%s%%' OR content LIKE '%%%s%%')", $word, $word ); } ``` `escape()` calls `mysqli::real_escape_string()`, which escapes characters like `'`, `\`, `NULL`, etc. — but explicitly does not escape `%` or `_`, as these are not SQL string delimiters. They are, however, LIKE pattern wildcards. Attack vector: A user submits a search term containing `_` or `%` as part of a 3+ character word (to bypass the `strlen <= 2` filter). Examples: • Search for `a_b` → LIKE becomes `'%a_b%'` → `_` matches any single character, e.g. matches `"aXb"`, `"a1b"`, `"azb"` — broader than the literal string `a_b` • Search for `te%t` → LIKE becomes `'%te%t%'` → matches `test`, `text`, `te12t`, etc. • Search for `_%_` → LIKE becomes `'%_%_%'` → matches any record with at least one character, effectively dumping all custom pages This allows an attacker to retrieve custom page content that would not appear in normal exact searches, bypassing intended search scope restrictions. PoC 1. Navigate to the phpMyFAQ search page (accessible to unauthenticated users by default). 2. Submit a search query: `_%_` (underscore, percent, underscore — length 3, bypasses the `<= 2` filter). 3. The backend executes: `WHERE (page_title LIKE '%_%_%' OR content LIKE '%_%_%')` 4. This matches all custom pages with at least one character in title or content — returning content that would not appear for a specific search term. Impact • Authentication required: None — search is publicly accessible • Affected component: `searchCustomPages()` in `Search.php`; custom pages (faqcustompages table) • Impact: Unauthenticated users can enumerate/disclose all custom page content regardless of the intended search term filter • Fix: Escape `%` and `_` in LIKE search terms before interpolation: ```php $word = str_replace(['\\', '%', '_'], ['\\\\', '\\%', '\\_'], $word); ``` Or use parameterized queries with properly escaped LIKE values.