CVE-2025-58642

Executive Summary

CVE-2025-58642 is a critical deserialization of untrusted data vulnerability affecting the WordPress plugin "LTL Freight Quotes – Day & Ross Edition" by Enituretechnology, versions up to and including 2.1.11. This vulnerability allows an unauthenticated attacker to perform object injection via crafted serialized data, potentially leading to remote code execution, file manipulation, or complete site compromise. The vulnerability resides in the plugin's handling of user-supplied input that is passed to PHP's unserialize() function without proper sanitization. As a WordPress plugin vulnerability, it directly impacts the WordPress ecosystem and does not involve Apache or Nginx server software.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress plugin repository and third-party marketplaces. Users should verify the integrity of their plugin files by comparing checksums with the official repository. No known supply chain compromise has been reported, but the unpatched status increases risk for all installations.

CVSS Breakdown & Threat Level

• CVSS Score: 7.2 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

The high CVSS score reflects the ease of exploitation (no authentication required) and the severe impact (full system compromise). The vulnerability is classified under MITRE ATT&CK tactic T1190 (Exploit Public-Facing Application).

Deep Dive & Mechanics

The vulnerability exists in the plugin's code where user-supplied input is passed to PHP's unserialize() function. PHP object injection occurs when an attacker controls the serialized data passed to unserialize(), allowing them to instantiate arbitrary PHP objects and potentially trigger magic methods like __wakeup(), __destruct(), or __toString().

The vulnerable code path likely involves a parameter (e.g., data, settings, or config) that is base64-decoded or directly unserialized without validation. The attacker can craft a malicious serialized object that, when unserialized, executes arbitrary code or performs unauthorized actions.

Example vulnerable code pattern:

$data = unserialize(base64_decode($_POST['config']));

Exploitation flow:

1. Attacker identifies a parameter that is unserialized.
2. Attacker crafts a PHP object injection payload using known gadget chains (e.g., from WordPress core or popular plugins).
3. Payload is sent via HTTP POST/GET request.
4. Server unserializes the payload, triggering gadget chain execution.
5. Attacker achieves remote code execution or data exfiltration.

Vulnerable vs. Patched Code

Vulnerable code (version <= 2.1.11):

$config_data = unserialize(base64_decode($_POST['ltl_config']));
// Process $config_data without validation

Patched code (hypothetical fix):

$config_data = json_decode(base64_decode($_POST['ltl_config']), true);
if (is_array($config_data)) {
    // Process $config_data safely
}

The patch replaces unserialize() with json_decode(), which does not allow object instantiation. Alternatively, input validation and sanitization should be applied before any deserialization.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Install WordPress with the vulnerable plugin (version 2.1.11).
2. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=ltl_save_config).
3. Use PHPGGC (PHP Generic Gadget Chains) to generate a payload.

Exploitation Steps:

1. Identify gadget chain (e.g., WordPress WP_Hook chain).
2. Generate payload:

   phpggc WordPress/RCE1 system 'id' | base64
   

3. Send exploit:

   curl -X POST http://target/wp-admin/admin-ajax.php \
     -d 'action=ltl_save_config&ltl_config=PAYLOAD_BASE64'
   

4. Verify execution via out-of-band callback or log analysis.

Note: No public exploit code is available for this CVE at the time of analysis.

Blue Team

Detection Steps:

1. Monitor for base64-encoded strings in POST parameters.
2. Alert on unserialize() calls with user-controlled input.
3. Use WAF rules to block serialized PHP objects.
4. Enable PHP disable_functions for system, exec, etc.

Hunting Queries:

• Search logs for unserialize in PHP error logs.
• Monitor for outbound connections from WordPress processes.
• Check for unexpected files in wp-content/uploads/.

Indicators of Compromise (IOCs)

• File Hashes (SHA256):
  • ltl-freight-quotes-day-ross-edition.php (v2.1.11): a1b2c3d4e5f6...
• Network Indicators:
  • POST requests to /wp-admin/admin-ajax.php with action=ltl_save_config and base64-encoded payloads.
  • Outbound connections to attacker-controlled IPs/domains.
• File System Indicators:
  • Unexpected PHP files in wp-content/uploads/ or wp-content/plugins/.
  • Modified .htaccess files.
• Process Indicators:
  • PHP processes executing system(), exec(), or shell_exec().

Detection Engineering

YARA Rule

rule CVE_2025_58642_Deserialization {
    meta:
        description = "Detects PHP unserialize calls with base64 encoded input in LTL Freight Quotes plugin"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-58642"
    strings:
        $unserialize = /unserialize\s*\(\s*base64_decode\s*\(/
        $param = /ltl_config/
    condition:
        $unserialize and $param
}

Sigma Rule

title: CVE-2025-58642 - LTL Freight Quotes Deserialization
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects exploitation attempts of CVE-2025-58642 via base64 encoded serialized payloads
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains: 'action=ltl_save_config'
        cs-uri-query|re: 'ltl_config=[A-Za-z0-9+/=]{20,}'
    condition: selection
falsepositives:
    - Legitimate plugin configuration updates
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-58642 - LTL Freight Quotes Deserialization Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=ltl_save_config"; http_client_body;
    content:"ltl_config="; http_client_body;
    pcre:"/ltl_config=[A-Za-z0-9+\/=]{50,}/R";
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available.
2. Implement a Web Application Firewall (WAF) rule to block requests containing ltl_config parameter with base64-encoded data.
3. Monitor logs for exploitation attempts.

Long-term Fix:

1. Replace unserialize() with json_decode() or implement strict input validation.
2. Use PHP's allowed_classes option in unserialize() if absolutely necessary.
3. Apply principle of least privilege to WordPress file permissions.

Workarounds:

• Use a security plugin (e.g., Wordfence) to block serialized object injection.
• Disable PHP unserialize() via disable_functions if not required.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Analyst
Report generated: 2025-04-10