CVE-2025-66430: CRITICAL Severity Vulnerability | Secably CVE Database

Summary

CVE-2025-66430 describes a critical Incorrect Access Control vulnerability affecting Plesk 18.0. This flaw allows unauthorized users to potentially gain elevated privileges, leading to complete system compromise. The vulnerability has a CVSS v3 score of 9.1, indicating its high severity and potential for widespread exploitation.

Technical Details

CVE-2025-66430 stems from an Incorrect Access Control issue within Plesk 18.0's handling of Password Protected Directories. Specifically, a flaw exists that allows Plesk users to potentially escalate their privileges to root level access on the Plesk server. This is achieved by exploiting a weakness in how Plesk manages permissions and access controls related to password-protected directories. An attacker could manipulate these directories or related configurations to bypass intended security restrictions and gain unauthorized access to sensitive system resources and functionalities. The exact mechanism involves [REDACTED - For security reasons, specific exploitation details are not provided here. Consult official vendor documentation and security advisories for more information].

Successful exploitation of this vulnerability grants the attacker complete control over the Plesk server, allowing them to execute arbitrary code, access sensitive data, modify system configurations, and potentially compromise other systems connected to the affected server. This vulnerability is particularly dangerous due to its ease of exploitation and the significant impact it can have on affected systems.

Affected Products and Versions

Plesk Obsidian 18.0 (All versions prior to the patched version)

Impact Assessment

Successful exploitation of CVE-2025-66430 can have severe consequences for affected Plesk servers and the organizations that rely on them. The vulnerability allows for complete system compromise, leading to a wide range of potential impacts.

Data Breach Risk: Attackers can gain access to sensitive data stored on the server, including customer data, financial information, and confidential business documents.
System Compromise: Attackers can gain complete control over the Plesk server, allowing them to execute arbitrary code, modify system configurations, and install malware.
Service Disruption: Attackers can disrupt the availability of services hosted on the Plesk server, leading to downtime and loss of revenue.
Reputational Damage: A successful attack can damage the reputation of the organization, leading to loss of customer trust and business opportunities.

Remediation

Immediate Actions

Apply the Latest Plesk Updates: Upgrade your Plesk Obsidian 18.0 installation to the latest version, which includes a patch for CVE-2025-66430.
Review Access Control Configurations: Carefully review your Plesk access control configurations to ensure that users have only the necessary privileges.
Monitor System Logs: Monitor system logs for any suspicious activity that may indicate an attempted exploitation of this vulnerability.

Long-term Solutions

Implement a Security Hardening Policy: Implement a comprehensive security hardening policy for your Plesk servers to minimize the risk of future vulnerabilities.
Regular Security Audits: Conduct regular security audits of your Plesk servers to identify and address potential vulnerabilities.
Web Application Firewall (WAF): Consider implementing a Web Application Firewall (WAF) to protect your Plesk servers from web-based attacks.

References

Detection & Scanning

Detecting CVE-2025-66430 requires careful examination of Plesk server logs and system configurations. Look for suspicious activity related to password-protected directories and user privilege escalation attempts. Vulnerability scanners can also be used to identify vulnerable Plesk installations.

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