EUVD-2025-21948

Comprehensive Technical Analysis of EUVD-2025-21948

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-21948 pertains to a PHP Object Injection flaw in the "Integration for Google Sheets and Contact Form 7, WPForms, Elementor, Ninja Forms" plugin for WordPress. This vulnerability is present in all versions up to and including 1.1.1. The issue arises from the deserialization of untrusted input within the verify_field_val() function, which can be exploited by unauthenticated attackers to inject a PHP Object.

The severity of this vulnerability is rated with a CVSS Base Score of 9.8, indicating a critical risk. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H highlights the following characteristics:

• Attack Vector (AV:N): Network, meaning the vulnerability is exploitable over the network.
• Attack Complexity (AC:L): Low, indicating that the attack is relatively straightforward to execute.
• Privileges Required (PR:N): None, meaning no authentication is required to exploit the vulnerability.
• User Interaction (UI:N): None, indicating that no user interaction is needed for the attack to succeed.
• Scope (S:U): Unchanged, meaning the vulnerability does not affect other security domains.
• Confidentiality (C:H): High impact on confidentiality.
• Integrity (I:H): High impact on integrity.
• Availability (A:H): High impact on availability.

2. Potential Attack Vectors and Exploitation Methods

The primary attack vector involves unauthenticated attackers sending crafted input to the verify_field_val() function, which deserializes the input without proper validation. This can lead to PHP Object Injection, allowing attackers to manipulate the application's behavior.

The presence of a Property-Oriented Programming (POP) chain in the Contact Form 7 plugin, which is often used alongside the vulnerable plugin, exacerbates the issue. Attackers can leverage this POP chain to delete arbitrary files, including critical files like wp-config.php. Deleting wp-config.php can result in a denial of service (DoS) or, in some cases, remote code execution (RCE) if the attacker can manipulate the configuration to execute malicious code.

3. Affected Systems and Software Versions

The vulnerability affects all versions of the "Integration for Google Sheets and Contact Form 7, WPForms, Elementor, Ninja Forms" plugin up to and including version 1.1.1. Any WordPress site using this plugin within the affected version range is at risk.

4. Recommended Mitigation Strategies

1. Immediate Patching: Upgrade the plugin to a version higher than 1.1.1 if a patched version is available.
2. Disable the Plugin: If a patched version is not available, consider disabling the plugin until a fix is released.
3. Input Validation: Implement additional input validation and sanitization measures to prevent untrusted data from being deserialized.
4. Monitoring and Logging: Enhance monitoring and logging to detect any suspicious activities related to the plugin.
5. Regular Audits: Conduct regular security audits and vulnerability assessments on all plugins and third-party integrations.
6. Backup and Recovery: Ensure that regular backups are taken and that a recovery plan is in place to restore the system in case of a successful attack.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to the European cybersecurity landscape, particularly for organizations and individuals using WordPress with the affected plugin. Given the widespread use of WordPress and the critical nature of the vulnerability, it could lead to widespread exploitation, resulting in data breaches, service disruptions, and potential financial losses.

The high CVSS score and the ease of exploitation make this vulnerability a prime target for cybercriminals. Organizations must prioritize patching and mitigation efforts to protect their digital assets and maintain compliance with regulations such as GDPR.

6. Technical Details for Security Professionals

• Vulnerable Function: verify_field_val()
• Exploitation Method: Deserialization of untrusted input leading to PHP Object Injection.
• POP Chain: The presence of a POP chain in the Contact Form 7 plugin allows for arbitrary file deletion.
• Critical File: Deletion of wp-config.php can lead to DoS or RCE.
• Mitigation: Implement strict input validation and sanitization, disable the plugin if necessary, and monitor for suspicious activities.

References:

• Wordfence Threat Intel
• WordPress Plugin Page
• Plugin Source Code
• Changeset

By addressing this vulnerability promptly and effectively, organizations can mitigate the risk of exploitation and protect their digital infrastructure.