CVE-2025-54336

Comprehensive Technical Analysis of CVE-2025-54336

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2025-54336 CISA Vulnerability Name: CVE-2025-54336 CVSS Score: 9.8

The vulnerability in Plesk Obsidian 18.0.70 involves a flaw in the _isAdminPasswordValid function, which uses a loose comparison (==) instead of a strict comparison (===). This allows an attacker to bypass authentication by exploiting the way PHP handles type juggling. Specifically, if the correct password is "0e" followed by any digit string, an attacker can log in using any string that evaluates to 0.0, such as "0e0".

Severity Evaluation:

• CVSS Score: 9.8 (Critical)
• Impact: This vulnerability can lead to unauthorized administrative access, potentially compromising the entire system.
• Exploitability: The vulnerability is relatively easy to exploit, requiring only knowledge of the specific password format.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Unauthorized Access: An attacker can gain administrative access by using a string that evaluates to 0.0 in the password field.
• Privilege Escalation: Once logged in, the attacker can perform any administrative actions, including modifying system settings, accessing sensitive data, and installing malicious software.

Exploitation Methods:

• Password Guessing: The attacker can attempt to log in using known vulnerable password formats (e.g., "0e0", "0e123456").
• Automated Scripts: Attackers can use automated scripts to brute-force the login process, trying various strings that evaluate to 0.0.

3. Affected Systems and Software Versions

Affected Software:

• Plesk Obsidian 18.0.70

Affected Systems:

• Any system running Plesk Obsidian 18.0.70, including web servers, hosting environments, and other systems managed by Plesk.

4. Recommended Mitigation Strategies

Immediate Actions:

• Patching: Apply the latest security patch provided by Plesk to address this vulnerability.
• Password Reset: Immediately reset all administrative passwords to ensure they do not match the vulnerable format.
• Monitoring: Increase monitoring of administrative login attempts to detect and respond to suspicious activity.

Long-Term Mitigations:

• Strict Comparisons: Ensure that all password comparisons use strict equality (===) to prevent type juggling issues.
• Regular Audits: Conduct regular security audits and code reviews to identify and fix similar vulnerabilities.
• User Education: Educate users about the importance of strong, unique passwords and the risks associated with weak passwords.

5. Impact on Cybersecurity Landscape

Broader Implications:

• Widespread Adoption: Plesk is widely used in web hosting environments, making this vulnerability a significant risk for many organizations.
• Trust and Reputation: Unauthorized access to administrative accounts can lead to data breaches, financial loss, and damage to an organization's reputation.
• Industry Awareness: This vulnerability highlights the importance of secure coding practices and the need for thorough testing and validation of authentication mechanisms.

6. Technical Details for Security Professionals

Vulnerable Code:

function _isAdminPasswordValid($password) {
    return $password == '0e123456'; // Vulnerable comparison
}

Secure Code:

function _isAdminPasswordValid($password) {
    return $password === '0e123456'; // Secure comparison
}

Exploitation Example: An attacker can exploit this vulnerability by attempting to log in with a password like "0e0", which evaluates to 0.0 in PHP due to type juggling.

Detection:

• Log Analysis: Review login attempt logs for patterns indicating the use of vulnerable password formats.
• Intrusion Detection Systems (IDS): Implement IDS rules to detect and alert on multiple failed login attempts with strings that evaluate to 0.0.

Response:

• Incident Response Plan: Have a well-defined incident response plan to quickly address any unauthorized access attempts.
• Forensic Analysis: Conduct forensic analysis to determine the extent of the breach and identify any compromised data or systems.

By addressing this vulnerability promptly and implementing robust security measures, organizations can mitigate the risk of unauthorized access and protect their systems from potential attacks.