CVE-2015-2775 in Mailman
Summary
by MITRE
Directory traversal vulnerability in GNU Mailman before 2.1.20, when not using a static alias, allows remote attackers to execute arbitrary files via a .. (dot dot) in a list name.
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Analysis
by VulDB Data Team • 05/03/2022
The vulnerability identified as CVE-2015-2775 represents a critical directory traversal flaw within GNU Mailman software versions prior to 2.1.20. This security weakness specifically manifests when the system operates without a static alias configuration, creating an exploitable condition that remote attackers can leverage to execute arbitrary files on the affected system. The vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied list names containing directory traversal sequences.
The technical exploitation of this vulnerability relies on the insertion of .. (dot dot) sequences within list names, which allows attackers to navigate beyond the intended directory structure and access files outside the designated mailman list directories. This flaw falls under the CWE-22 category of Directory Traversal, where insufficient validation of input data enables unauthorized access to system resources. The vulnerability is particularly dangerous because it can be exploited remotely without requiring authentication, making it accessible to any attacker who can interact with the mailman service.
When an attacker successfully exploits this vulnerability, they can execute arbitrary code on the target system with the privileges of the mailman process, which typically runs with elevated permissions to manage email lists and user data. This execution capability can lead to complete system compromise, data exfiltration, or further lateral movement within the network infrastructure. The impact extends beyond simple file access as the attacker can potentially modify system configurations, install backdoors, or manipulate email communications managed by the vulnerable mailman installation.
The operational implications of this vulnerability are severe for organizations relying on GNU Mailman for email list management, particularly those operating older versions without proper security updates. System administrators may face unauthorized access to sensitive email communications, user data exposure, and potential disruption of email services. The vulnerability affects both the confidentiality and integrity of email systems, as attackers can not only read files but also modify system components and email configurations. Organizations with multiple mailman installations across different servers face compounded risk, as a single vulnerable instance can serve as a foothold for broader network infiltration.
Mitigation strategies for CVE-2015-2775 primarily involve immediate patching of GNU Mailman installations to version 2.1.20 or later, which includes proper input sanitization and validation mechanisms. Additionally, system administrators should implement proper access controls and network segmentation to limit exposure of mailman services to untrusted networks. Input validation should be enhanced to reject any list names containing directory traversal sequences, and the system should be configured to use static aliases when possible. Security monitoring should be implemented to detect suspicious list creation attempts or unusual file access patterns. Organizations should also consider implementing web application firewalls and intrusion detection systems to provide additional layers of protection against exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing proper security controls in email infrastructure to prevent unauthorized access and system compromise.