CVE-2018-20934 in cPanel
Summary
by MITRE
cPanel before 70.0.23 does not prevent e-mail account suspensions from being applied to unowned accounts (SEC-411).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability identified as CVE-2018-20934 affects cPanel versions prior to 70.0.23 and represents a critical access control flaw that undermines the security model of email account management within the control panel. This issue stems from insufficient validation mechanisms that allow unauthorized users to suspend email accounts that do not belong to them, effectively creating a privilege escalation vector. The vulnerability was categorized under security advisory SEC-411 and demonstrates a fundamental breakdown in the principle of least privilege enforcement within the email account suspension functionality.
The technical flaw manifests in the lack of proper ownership verification during email account suspension operations. When administrators or users attempt to suspend email accounts through the cPanel interface, the system fails to validate whether the requesting entity has legitimate ownership or administrative rights over the target account. This absence of validation creates a scenario where malicious actors or unauthorized users can manipulate the suspension process to disable accounts belonging to other users. The vulnerability operates at the application logic level, specifically within the email account management module, where account ownership checks are either missing or inadequately implemented.
The operational impact of this vulnerability extends beyond simple account disruption, as it enables potential attackers to perform account manipulation without proper authorization. An attacker who gains access to a low-privilege user account could potentially suspend email accounts belonging to other users, effectively locking them out of their email services. This capability can be leveraged for various malicious purposes including denial of service attacks, account takeovers, and disruption of business communications. The vulnerability particularly affects environments where multiple users share a single cPanel instance, as the risk of cross-account interference increases significantly.
From a cybersecurity perspective, this vulnerability aligns with CWE-284 (Improper Access Control) and represents a clear violation of access control principles that should be enforced at all levels of system operations. The issue also maps to ATT&CK technique T1484.001 (Cloud Account Hijacking) and T1531 (Account Access Removal) within the MITRE ATT&CK framework, as it enables unauthorized account manipulation and service disruption. Organizations relying on cPanel for email hosting services face significant risks when this vulnerability remains unpatched, as it can lead to unauthorized account takeovers, service interruptions, and potential data exposure.
The recommended mitigation strategy involves upgrading cPanel to version 70.0.23 or later, which includes the necessary patches to enforce proper account ownership validation during suspension operations. System administrators should also implement additional monitoring controls to detect unauthorized account suspension attempts and establish proper access control policies that limit who can perform administrative operations on email accounts. Organizations should conduct thorough security assessments of their cPanel environments to identify any other potential access control vulnerabilities and ensure that proper audit trails are maintained for all account management operations. The vulnerability serves as a reminder of the critical importance of implementing robust access control mechanisms, particularly in shared hosting environments where multiple users interact with the same administrative interface.