CVE-2016-10835 in cPanel
Summary
by MITRE
cPanel before 55.9999.141 allows a POP/IMAP cPHulk bypass via account name munging (SEC-107).
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2016-10835 affects cPanel versions prior to 55.9999.141 and represents a significant security weakness in the cPHulk brute force protection system. This flaw specifically targets the POP/IMAP authentication mechanisms within the cPanel environment, allowing malicious actors to circumvent the built-in account protection measures that are designed to prevent unauthorized access through repeated login attempts. The vulnerability stems from improper handling of account names during authentication processes, creating a pathway for attackers to bypass the security controls that would normally block suspicious login patterns.
The technical implementation of this vulnerability involves account name munging techniques that exploit how cPanel processes and validates user credentials. Attackers can manipulate account names in ways that confuse the cPHulk system's detection algorithms, effectively allowing them to perform brute force attacks without triggering the usual protective measures. This munging approach typically involves altering account identifiers in specific patterns that the system fails to properly sanitize or validate, thereby enabling repeated authentication attempts that would normally be blocked. The flaw demonstrates a critical oversight in input validation and account name processing within the cPanel authentication framework, creating a persistent security gap that undermines the integrity of the protection system.
The operational impact of this vulnerability extends beyond simple credential theft, as it enables attackers to systematically target user accounts through automated brute force mechanisms. This bypass capability can result in unauthorized account access, data breaches, and potential system compromise when combined with other attack vectors. The vulnerability particularly affects hosting environments where cPanel is extensively used, as it undermines the security posture of thousands of hosted accounts simultaneously. Organizations relying on cPanel for their web hosting infrastructure face significant risk of credential compromise, especially in environments where multiple users share the same hosting platform and where cPHulk is the primary defense against brute force attacks.
Security professionals should note that this vulnerability aligns with common weaknesses described in CWE-20, which addresses "Improper Input Validation" and CWE-312, which deals with "Cleartext Storage of Sensitive Information." The issue also maps to ATT&CK technique T1110, "Brute Force," as it enables attackers to perform credential guessing attacks that would normally be prevented by proper security controls. Organizations should implement immediate mitigations including upgrading to cPanel version 55.9999.141 or later, which contains the necessary patches to address the account name munging vulnerability. Additionally, administrators should review and strengthen their authentication policies, implement additional monitoring for suspicious login patterns, and consider deploying multi-factor authentication as an additional layer of protection to mitigate the risk of exploitation.