CVE-2025-53461

Executive Summary

CVE-2025-53461 is a Server-Side Request Forgery (SSRF) vulnerability discovered in the Beaf image-compare-block WordPress plugin by Binsaifullah. This flaw allows an authenticated attacker with low privileges to make the server send crafted HTTP requests to internal or external resources, potentially leading to information disclosure or internal network reconnaissance. The vulnerability affects all versions of the plugin up to and including 1.6.2. As of this report, no official patch has been released, and the vendor's patch status remains unknown.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin ecosystem. The plugin is distributed via the official WordPress plugin repository and can be installed directly from the WordPress admin dashboard. Since no patch is available, users are advised to consider disabling or removing the plugin until a fix is released. The lack of a patch increases the risk of supply chain attacks, as malicious actors could exploit this SSRF to pivot into internal networks or exfiltrate sensitive data.

CVSS Breakdown & Threat Level

• CVSS Score: 4.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: None
• Availability Impact: None

The low EPSS score (0.0%) suggests that exploitation is not currently widespread, but the vulnerability's simplicity and the lack of a patch make it a potential target for automated scanning.

Deep Dive & Mechanics

The SSRF vulnerability in the Beaf image-compare-block plugin arises from improper validation of user-supplied URLs when fetching external images or resources. The plugin likely uses a server-side function (e.g., wp_remote_get() or file_get_contents()) to retrieve images based on user input without adequately restricting the target host or protocol. An attacker can manipulate this input to make the server send requests to internal IP addresses (e.g., 127.0.0.1, 10.0.0.1) or cloud metadata endpoints (e.g., http://169.254.169.254/latest/meta-data/).

The vulnerability is triggered via the plugin's block editor interface, where a user can specify a URL for an image comparison. By crafting a malicious URL, the attacker can force the server to interact with internal services, potentially leaking sensitive information such as cloud instance metadata, internal API keys, or database credentials.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison cannot be provided. However, based on common SSRF patterns, the vulnerable code likely resembles:

// Vulnerable code (hypothetical)
$image_url = $_POST['image_url'];
$image_data = file_get_contents($image_url);

A patched version would include validation such as:

// Patched code (hypothetical)
$image_url = $_POST['image_url'];
if (filter_var($image_url, FILTER_VALIDATE_URL) && 
    preg_match('/^https?:\/\/([a-zA-Z0-9.-]+\.)?(trusted-domain\.com|cdn\.example\.com)/', $image_url)) {
    $image_data = file_get_contents($image_url);
} else {
    // Reject request
}

Exploitation & Lab Setup

Red Team

To exploit this vulnerability in a controlled lab environment:

1. Setup: Install WordPress with the Beaf plugin version 1.6.2 on a local server (e.g., using Docker).
2. Craft Payload: Use a tool like Burp Suite or cURL to send a POST request to the plugin's AJAX endpoint with a malicious URL.
3. Example Request:

   POST /wp-admin/admin-ajax.php HTTP/1.1
   Host: target-site.com
   Content-Type: application/x-www-form-urlencoded
   
   action=beaf_fetch_image&image_url=http://169.254.169.254/latest/meta-data/
   

4. Observe Response: The server will return the content of the internal metadata endpoint, revealing cloud instance information.

Blue Team

To detect and defend against this exploit:

1. Monitor Outbound Requests: Use network monitoring tools to detect unusual outbound HTTP requests from the WordPress server to internal IPs or cloud metadata endpoints.
2. Web Application Firewall (WAF): Deploy rules to block requests containing internal IP addresses (e.g., 127.0.0.1, 10.0.0.0/8, 169.254.169.254) in URL parameters.
3. Log Analysis: Review web server logs for patterns like image_url=http:// followed by private IP ranges.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound HTTP requests to internal IP addresses (e.g., 10.x.x.x, 172.16.x.x, 192.168.x.x)
  • Requests to 169.254.169.254 (cloud metadata endpoint)
  • Requests to 127.0.0.1 or localhost
• File IOCs:
  • Modified plugin files in /wp-content/plugins/beaf/
  • Suspicious entries in WordPress debug logs
• Behavioral IOCs:
  • Unusual server load due to repeated SSRF attempts
  • Unexpected data in HTTP response bodies (e.g., cloud metadata JSON)

Detection Engineering

YARA Rule

rule CVE_2025_53461_SSRF_Beaf {
    meta:
        description = "Detects SSRF exploitation attempts against Beaf image-compare-block plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-53461"
    strings:
        $ssrf_payload = /image_url=http:\/\/(127\.0\.0\.1|localhost|169\.254\.169\.254|10\.\d{1,3}\.\d{1,3}\.\d{1,3}|172\.(1[6-9]|2\d|3[01])\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3})/ nocase
        $plugin_path = "wp-content/plugins/beaf"
    condition:
        $ssrf_payload and $plugin_path
}

Sigma Rule

title: CVE-2025-53461 SSRF Exploitation Attempt
id: 8a3f7c2e-5b1d-4a9f-8c6e-2d1f3a4b5c6d
status: experimental
description: Detects HTTP requests targeting internal IPs via the Beaf plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=beaf_fetch_image'
        cs-uri-query|contains|all:
            - 'image_url=http://'
            - '127.0.0.1'
    condition: selection
falsepositives:
    - Legitimate use of internal image URLs (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-53461 SSRF Exploitation Attempt"; flow:to_server,established; content:"POST"; http_method; content:"action=beaf_fetch_image"; http_client_body; content:"image_url=http://"; http_client_body; pcre:"/image_url=http:\/\/(127\.0\.0\.1|localhost|169\.254\.169\.254|10\.\d{1,3}\.\d{1,3}\.\d{1,3}|172\.(1[6-9]|2\d|3[01])\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3})/Ri"; sid:1000001; rev:1;)

Remediation & Mitigation

Since no official patch is available, the following mitigations are recommended:

1. Disable the Plugin: Immediately deactivate and remove the Beaf image-compare-block plugin from all WordPress installations.
2. Web Application Firewall (WAF): Deploy WAF rules to block SSRF payloads targeting internal IPs.
3. Network Segmentation: Restrict outbound HTTP access from the WordPress server to only trusted external hosts.
4. Monitor Logs: Enable detailed logging and monitor for SSRF patterns.
5. Alternative Plugin: Replace with a similar, actively maintained plugin that does not have SSRF vulnerabilities.

Valters IT
Securing Digital Frontiers