Attack Chain

1. An attacker authenticates to the WordPress application.
2. The attacker crafts a malicious HTTP POST request targeting the admin-ajax.php endpoint.
3. The POST request includes the action parameter set to ufbl_get_entry_detail_action.
4. The attacker injects SQL code into the entry_id POST parameter.
5. The vulnerable plugin processes the entry_id parameter without proper sanitization, incorporating the injected SQL code into a database query.
6. The crafted SQL query is executed against the WordPress database.
7. Depending on the injected SQL code, the attacker can extract sensitive data, modify database entries, or create new administrative accounts.
8. The attacker leverages the gained access to compromise the entire WordPress installation.

Impact

Successful exploitation of this SQL injection vulnerability allows attackers to read, modify, or delete arbitrary data within the WordPress database. This can lead to sensitive data leakage, defacement of the website, or complete takeover of the WordPress installation. Depending on the attacker’s goals, they may escalate privileges to create new administrative accounts, inject malicious code into the website, or use the compromised server as a staging point for further attacks.

Recommendation

• Deploy the Sigma rule Detect CVE-2018-25352 Exploitation Attempt — WordPress Ultimate Form Builder SQLi to identify potentially malicious requests targeting the vulnerable endpoint and parameter.
• Upgrade the Ultimate Form Builder Lite plugin to a version greater than 1.3.7 to patch the CVE-2018-25352 vulnerability.
• Monitor web server logs for suspicious POST requests to admin-ajax.php with the ufbl_get_entry_detail_action action and SQL-like syntax in the entry_id parameter.