CVE-2018-20883 in cPanel
Summary
by MITRE
cPanel before 74.0.8 allows FTP access during account suspension (SEC-449).
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Analysis
by VulDB Data Team • 07/17/2020
The vulnerability identified as CVE-2018-20883 affects cPanel versions prior to 74.0.8 and represents a critical access control flaw that undermines the security posture of web hosting environments. This issue specifically relates to the improper handling of FTP access permissions when user accounts are suspended, creating a persistent security risk that can be exploited by unauthorized parties. The vulnerability was categorized under security advisory SEC-449, indicating its significance within the cPanel security framework and its potential impact on hosting providers and their customers.
The technical flaw manifests in the account suspension mechanism where cPanel fails to properly revoke FTP access privileges even when an account is suspended. This occurs due to a logical error in the permission management system that does not adequately enforce access controls during account state transitions. When an account is suspended through the cPanel interface, the system should immediately terminate all active connections and revoke access to all services including FTP. However, the vulnerability allows FTP sessions that were active before suspension to continue operating, and new FTP connections to be established despite the account being in a suspended state. This represents a failure in the principle of least privilege and demonstrates a clear breakdown in the access control model.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential data breaches, service disruption, and compliance violations for hosting providers. Attackers can exploit this weakness to maintain access to suspended accounts and potentially exfiltrate sensitive data, manipulate files, or conduct malicious activities using the compromised FTP credentials. The vulnerability affects hosting environments where multiple customers share the same infrastructure, as it allows for cross-account compromise where one suspended account's FTP access can be used to access files or services belonging to other accounts. This creates a significant risk for shared hosting environments and can lead to widespread data exposure across multiple customer accounts. The vulnerability also impacts the integrity of account suspension mechanisms, undermining the trust model that hosting providers rely on to manage customer access and security.
Mitigation strategies for CVE-2018-20883 require immediate implementation of the vendor-provided patch for cPanel version 74.0.8 and subsequent releases. Organizations should conduct comprehensive security assessments to identify any active FTP sessions that may have been established during account suspension periods and terminate these connections immediately. Network administrators should implement additional monitoring controls to detect unusual FTP activity patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-693, which addresses protection mechanism failures, and represents a clear violation of the principle of least privilege as outlined in the MITRE ATT&CK framework under the technique of privilege escalation. Hosting providers should also consider implementing automated account monitoring systems that can detect and alert on suspension state anomalies, ensuring that access controls are properly enforced across all services including FTP, SSH, and web access. Regular security audits and penetration testing should be conducted to verify that account suspension mechanisms are functioning correctly and that no similar access control flaws exist within the hosting environment.