CVE-2016-4069 in RoundCube
Summary
by MITRE
Cross-site request forgery (CSRF) vulnerability in Roundcube Webmail before 1.1.5 allows remote attackers to hijack the authentication of users for requests that download attachments and cause a denial of service (disk consumption) via unspecified vectors.
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Analysis
by VulDB Data Team • 09/14/2022
The CVE-2016-4069 vulnerability represents a critical cross-site request forgery flaw discovered in Roundcube Webmail versions prior to 1.1.5, demonstrating a fundamental weakness in the application's session management and request validation mechanisms. This vulnerability operates through the exploitation of the webmail application's failure to properly validate the origin of incoming requests, allowing malicious actors to craft deceptive requests that appear to originate from legitimate authenticated users. The flaw exists within the application's handling of attachment download functionality, where the system does not adequately verify that requests are initiated by the genuine user rather than by an attacker exploiting the CSRF vulnerability.
The technical implementation of this vulnerability stems from the absence of proper anti-CSRF tokens or origin validation checks within the webmail's request processing pipeline. When users navigate to the attachment download functionality, the application fails to enforce strict validation of the request source, creating an attack surface where remote adversaries can construct malicious web pages or exploit existing user sessions to trigger unauthorized attachment downloads. This weakness enables attackers to manipulate the application's behavior through crafted requests that bypass normal authentication checks, effectively allowing them to perform actions on behalf of authenticated users without their knowledge or consent.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it creates conditions that can lead to significant denial of service scenarios through disk consumption. Attackers can leverage this vulnerability to repeatedly trigger attachment downloads, potentially overwhelming the target system's storage resources and causing legitimate users to experience service degradation or complete unavailability of the webmail service. The malicious exploitation can result in rapid disk space exhaustion, particularly when attackers target large attachment files or execute repeated download operations, creating a cascading effect that impacts system performance and availability. This aspect of the vulnerability aligns with attack patterns described in the attack technique matrix under the MITRE ATT&CK framework where adversaries leverage application vulnerabilities to consume system resources and create service disruptions.
The security implications of CVE-2016-4069 demonstrate the importance of implementing robust input validation and session management controls within web applications. The vulnerability's classification under CWE-352 indicates that it falls into the category of cross-site request forgery, which represents one of the most common and dangerous web application security flaws. Organizations utilizing Roundcube Webmail should prioritize immediate patching to address this vulnerability, as the attack surface remains exploitable for any version prior to 1.1.5. The recommended mitigation strategy involves implementing proper CSRF token validation mechanisms, enforcing strict request origin checks, and ensuring that all user-initiated actions require proper authentication verification before execution. Additionally, system administrators should monitor for unusual attachment download patterns and implement rate limiting controls to prevent abuse of the affected functionality. The vulnerability serves as a reminder of the critical need for regular security updates and comprehensive application security testing to prevent exploitation of known weaknesses that could lead to both unauthorized access and service disruption scenarios.