CVE-2017-18415 in cPanel
Summary
by MITRE
cPanel before 67.9999.103 allows code execution in the context of the mailman account because of incorrect environment-variable filtering (SEC-302).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability identified as CVE-2017-18415 affects cPanel versions prior to 67.9999.103 and represents a critical code execution flaw that enables attackers to run arbitrary commands with the privileges of the mailman account. This vulnerability stems from inadequate filtering of environment variables within the cPanel mailman integration, creating a path for malicious input to be processed without proper sanitization. The security issue was documented under SEC-302 and demonstrates a classic case of insecure environment variable handling that can lead to privilege escalation and remote code execution within the affected system.
The technical flaw manifests through improper environment variable filtering mechanisms that fail to adequately validate or sanitize input parameters passed to the mailman service. When cPanel processes mailman-related operations, it does not properly isolate or sanitize environment variables, allowing crafted input to be interpreted as executable commands. This vulnerability specifically impacts the mailman account context, meaning that successful exploitation would grant attackers the ability to execute code with the privileges associated with the mailman system user. The flaw essentially creates a command injection vector where attacker-controlled environment variables can be leveraged to execute arbitrary shell commands on the server.
From an operational impact perspective, this vulnerability presents a significant threat to cPanel hosting environments as it allows for remote code execution with mailman privileges, which typically have access to email processing functionality and potentially system resources. The mailman account often has elevated permissions within the hosting environment, making this a valuable target for attackers seeking to establish persistent access or escalate privileges further. The vulnerability can be exploited remotely without requiring authentication, making it particularly dangerous for hosting providers and organizations relying on cPanel for email management services.
Organizations should immediately apply the security patch released with cPanel version 67.9999.103 to address this vulnerability. The mitigation strategy involves updating to the patched version and implementing additional monitoring for suspicious mailman-related activities. System administrators should also review and harden environment variable handling processes throughout the cPanel installation, ensuring that all input is properly validated and sanitized before processing. Security controls should include monitoring for unusual mailman process behavior and implementing network segmentation to limit potential lateral movement if exploitation occurs. This vulnerability aligns with CWE-78, which addresses improper neutralization of special elements used in OS commands, and maps to attack techniques in the ATT&CK framework under command and control phases where adversaries establish persistent access through system-level vulnerabilities.