CVE-2023-2636 Overview
CVE-2023-2636 is a SQL injection vulnerability in the AN_GradeBook WordPress plugin through version 5.0.1. The plugin fails to properly sanitize and escape a user-supplied parameter before using it in a SQL statement. Authenticated users with a role as low as subscriber can exploit this flaw to inject arbitrary SQL queries. The weakness is classified under CWE-89, Improper Neutralization of Special Elements used in an SQL Command.
Critical Impact
Authenticated subscribers can extract database contents, modify records, and compromise the integrity of WordPress sites running AN_GradeBook 5.0.1 or earlier.
Affected Products
- AN_GradeBook WordPress plugin versions through 5.0.1
- WordPress sites with subscriber-level registration enabled
- Any WordPress installation that has installed and activated the AN_GradeBook plugin
Discovery Timeline
- 2023-07-17 - CVE-2023-2636 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2023-2636
Vulnerability Analysis
The AN_GradeBook plugin accepts a parameter from authenticated requests and concatenates it directly into a SQL statement. The plugin neither sanitizes the input nor uses parameterized queries. Attackers can break out of the intended SQL context by supplying crafted input containing SQL metacharacters. The vulnerability is reachable by users holding the lowest WordPress privilege tier, the subscriber role, which is commonly granted automatically when open registration is enabled.
Exploitation grants attackers read and write access to the underlying WordPress database. Successful attacks can disclose wp_users password hashes, session tokens stored in wp_usermeta, and arbitrary post or option data. Attackers can also use UPDATE-style payloads to escalate privileges by modifying their own user record.
Root Cause
The defect stems from string concatenation of untrusted input into a SQL query without applying $wpdb->prepare() or equivalent escaping. WordPress provides safe query APIs, but the affected plugin code path bypasses them. This pattern matches CWE-89 and is the standard signature of classic SQL injection in PHP web applications.
Attack Vector
The attack is delivered over the network against the vulnerable WordPress endpoint exposed by the plugin. The attacker must hold valid subscriber credentials, which are trivial to obtain on sites permitting self-registration. After authenticating, the attacker submits a request containing SQL injection syntax in the vulnerable parameter. Public exploitation details are documented in the Packet Storm advisory and the WPScan vulnerability report. An EPSS score of 4.6% places this CVE in the 89th percentile for exploitation likelihood.
No verified proof-of-concept code is included here. Refer to the linked Packet Storm advisory for the technical request structure used by published exploits.
Detection Methods for CVE-2023-2636
Indicators of Compromise
- HTTP requests to AN_GradeBook plugin endpoints containing SQL metacharacters such as UNION SELECT, SLEEP(, --, or 0x hex sequences in parameter values
- Unexpected new administrator accounts in wp_users or role changes in wp_usermeta
- WordPress database error messages in web server logs originating from AN_GradeBook PHP files
- Outbound DNS or HTTP callbacks from the database server consistent with out-of-band SQLi exfiltration
Detection Strategies
- Inspect web access logs for requests targeting AN_GradeBook plugin paths under /wp-content/plugins/an-gradebook/ with anomalous query parameters
- Deploy a web application firewall rule set such as OWASP CRS to flag SQL injection signatures against WordPress endpoints
- Correlate subscriber-tier authentication events with subsequent database error responses to surface low-privilege exploitation attempts
Monitoring Recommendations
- Enable WordPress debug logging and forward wp-content/debug.log to a central log platform for SQL error detection
- Monitor MySQL slow query and error logs for malformed queries originating from the WordPress application user
- Alert on creation of new WordPress administrator accounts and on modifications to the wp_options table outside of change windows
How to Mitigate CVE-2023-2636
Immediate Actions Required
- Deactivate and remove the AN_GradeBook plugin from all WordPress installations until a fixed release is confirmed
- Disable open user registration or restrict the default role to prevent attackers from obtaining subscriber accounts
- Rotate WordPress administrator passwords and invalidate active sessions if exploitation is suspected
- Audit the wp_users and wp_usermeta tables for unauthorized accounts or role escalations
Patch Information
No vendor patch is referenced in the NVD entry for CVE-2023-2636. The vulnerability affects AN_GradeBook through version 5.0.1, and the plugin appears to have limited active maintenance. Site operators should treat removal of the plugin as the primary remediation path. Consult the WPScan vulnerability report for any updates on a fixed version.
Workarounds
- Block external access to AN_GradeBook plugin endpoints at the reverse proxy or WAF layer
- Restrict WordPress login and registration pages by IP allowlist where feasible
- Apply database-level least privilege so the WordPress MySQL user cannot perform FILE, CREATE USER, or cross-database operations
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
