CVE-2016-6893 in Mailman
Summary
by MITRE
Cross-site request forgery (CSRF) vulnerability in the user options page in GNU Mailman 2.1.x before 2.1.23 allows remote attackers to hijack the authentication of arbitrary users for requests that modify an option, as demonstrated by gaining access to the credentials of a victim's account.
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Analysis
by VulDB Data Team • 09/14/2022
The CVE-2016-6893 vulnerability represents a critical cross-site request forgery flaw in GNU Mailman versions prior to 2.1.23, specifically affecting the user options page functionality. This vulnerability operates under the Common Weakness Enumeration category CWE-352, which classifies cross-site request forgery as a significant web application security weakness. The flaw enables remote attackers to manipulate authenticated sessions by tricking users into executing unintended actions against a web application with which they are authenticated. In the context of GNU Mailman, this vulnerability specifically targets the user options page where legitimate users can modify their account settings and preferences.
The technical implementation of this CSRF vulnerability stems from the absence of proper anti-forgery token validation mechanisms within the user options page forms. When a user navigates to the options page and submits modifications, the application fails to verify that the request originates from the legitimate user interface rather than from a malicious third-party website. Attackers can construct malicious web pages or exploit existing vulnerabilities in other sites to automatically submit forged requests to the GNU Mailman application. These forged requests can modify user options including account credentials, subscription settings, and other sensitive configuration parameters without the user's knowledge or consent.
The operational impact of this vulnerability extends beyond simple session hijacking to encompass complete account compromise and unauthorized access to email lists and user data. Successful exploitation allows attackers to gain access to victim accounts, potentially enabling them to read private emails, modify subscriptions, change passwords, and even gain administrative privileges if the affected user has elevated permissions. The vulnerability is particularly dangerous because it operates at the user authentication level, meaning that once an attacker successfully hijacks a user's session, they can perform any action that the legitimate user is authorized to perform within the GNU Mailman application. This creates a significant risk for organizations relying on GNU Mailman for email list management and user communication services.
Mitigation strategies for CVE-2016-6893 should focus on implementing robust anti-forgery token mechanisms and ensuring proper validation of user requests. Organizations should immediately upgrade to GNU Mailman version 2.1.23 or later, which includes the necessary patches to address this vulnerability. Additionally, administrators should implement proper input validation and request origin verification mechanisms. The mitigation approach aligns with ATT&CK technique T1566 which addresses credential access through social engineering and web application attacks. Security teams should also consider implementing web application firewalls and monitoring for suspicious request patterns that may indicate CSRF attack attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other web applications within the organization's infrastructure, as CSRF vulnerabilities often occur in similar authentication and session management patterns across various web platforms.