CVE-2025-24701

Executive Summary

CVE-2025-24701 is a Server-Side Request Forgery (SSRF) vulnerability in the WordPress plugin Chained Quiz, affecting versions from n/a through 1.3.2.9. 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 is classified as SSRF (CWE-918) and has a CVSS score of 4.4 (Medium). No public exploit code or patch details are currently available, and the EPSS score is 0.0%, indicating low exploitation activity at this time.

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 vendor (Bob) and apply patches as soon as they become available. Since the patch status is unknown, manual mitigation is required.

CVSS Breakdown & Threat Level

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

The threat level is medium due to the low complexity and network attack vector, but the impact is limited to low confidentiality loss. The vulnerability requires authentication, reducing the attack surface.

Deep Dive & Mechanics

The SSRF vulnerability in Chained Quiz arises from insufficient validation of user-supplied URLs or endpoints within the plugin's functionality. When the plugin processes requests that involve fetching external resources (e.g., quiz data, images, or API calls), it does not properly restrict the target host or protocol. An attacker with low-level access (e.g., subscriber or contributor) can craft a request that forces the server to make HTTP requests to arbitrary destinations, including internal IP addresses (e.g., 127.0.0.1, 10.0.0.0/8) or cloud metadata endpoints (e.g., 169.254.169.254).

The vulnerability likely exists in a function that handles URL parameters or redirects without checking if the target is internal. For example, a parameter like quiz_url might be passed to wp_remote_get() or file_get_contents() without proper sanitization.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is presumed to be in the plugin's core logic. A typical vulnerable pattern in PHP would be:

// Vulnerable code (example)
$url = $_GET['quiz_url'];
$response = wp_remote_get($url); // No validation

A patched version would include validation:

// Patched code (example)
$url = $_GET['quiz_url'];
if (filter_var($url, FILTER_VALIDATE_URL) && !is_internal_ip($url)) {
    $response = wp_remote_get($url);
} else {
    // Reject request
}

Exploitation & Lab Setup

Red Team

1. Setup: Install WordPress with Chained Quiz plugin version 1.3.2.9 on a local server (e.g., using Docker).
2. Authentication: Obtain low-privilege credentials (e.g., subscriber).
3. Exploit: Send a crafted HTTP request to the vulnerable endpoint, e.g.:

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

4. Verify: Check server logs or response for internal data.

Blue Team

1. Monitor: Look for outbound HTTP requests to internal IP ranges (127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) from the web server.
2. Log Analysis: Review web server logs for unusual url parameters or wp_remote_get calls.
3. Network Segmentation: Ensure the web server cannot reach sensitive internal services.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP requests to internal IP addresses (e.g., 10.x.x.x, 192.168.x.x, 127.0.0.1).
• Logs: Web server logs containing url parameters pointing to internal hosts.
• File: Modified plugin files or unexpected files in /wp-content/plugins/chained-quiz/.
• Process: Unusual curl or wget processes spawned by the web server user.

Detection Engineering

YARA Rule

rule CVE_2025_24701_SSRF_ChainedQuiz {
    meta:
        description = "Detects SSRF exploitation attempts against Chained Quiz plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-24701"
    strings:
        $url_param = "url=" nocase
        $internal_ip = /(127\.0\.0\.1|10\.\d{1,3}\.\d{1,3}\.\d{1,3}|172\.(1[6-9]|2[0-9]|3[0-1])\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|169\.254\.\d{1,3}\.\d{1,3})/
        $metadata = "169.254.169.254"
    condition:
        $url_param and ($internal_ip or $metadata)
}

Sigma Rule

title: CVE-2025-24701 SSRF Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects SSRF attempts against Chained Quiz plugin via URL parameter
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=chained_quiz_fetch'
        cs-uri-query|contains: 'url='
    filter:
        cs-uri-query|contains:
            - '127.0.0.1'
            - '10.'
            - '172.16.'
            - '192.168.'
            - '169.254.'
    condition: selection and filter
falsepositives:
    - Legitimate use of internal URLs by administrators
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-24701 SSRF Exploitation Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=chained_quiz_fetch"; http_client_body; content:"url="; http_client_body; pcre:"/(127\.0\.0\.1|10\.\d{1,3}\.\d{1,3}\.\d{1,3}|172\.(1[6-9]|2[0-9]|3[0-1])\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|169\.254\.\d{1,3}\.\d{1,3})/Ri"; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Disable the Chained Quiz plugin until a patch is available.
2. Network: Implement egress filtering to block outbound requests to internal IP ranges from the web server.
3. WAF: Deploy a Web Application Firewall rule to block requests containing url= parameters pointing to internal IPs.
4. Monitoring: Enable logging for all outbound HTTP requests and alert on anomalies.
5. Update: Monitor the WordPress plugin repository for updates and apply patches immediately.

Valters IT
Securing Digital Frontiers