CVE-2013-3694 in BlackBerry Link
Summary
by MITRE
BlackBerry Link before 1.2.1.31 on Windows and before 1.1.1 build 39 on Mac OS X does not require authentication for remote file-access folders, which allows remote attackers to read or create arbitrary files via IPv6 WebDAV requests, as demonstrated by a CSRF attack involving DNS rebinding.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability described in CVE-2013-3694 represents a critical authentication bypass flaw in BlackBerry Link software versions prior to 1.2.1.31 on Windows and 1.1.1 build 39 on Mac OS X. This weakness stems from insufficient access controls within the WebDAV implementation that allows unauthorized remote attackers to gain access to file-access folders without proper authentication mechanisms. The vulnerability specifically affects the remote file access functionality that is exposed through IPv6 connections, creating a significant security gap that can be exploited by malicious actors. The flaw is particularly concerning because it enables attackers to perform arbitrary file read and write operations, potentially leading to data exfiltration, system compromise, or unauthorized modifications to critical files. The vulnerability demonstrates how insecure default configurations in network services can create persistent attack vectors that remain unpatched for extended periods.
The technical implementation of this vulnerability involves the WebDAV protocol's improper handling of authentication requirements within the BlackBerry Link application. When the application exposes WebDAV endpoints for remote file access, it fails to enforce proper authentication checks for IPv6 connections, allowing attackers to bypass the normal authentication flow. This authentication bypass occurs through the WebDAV protocol implementation that does not adequately validate user credentials or session tokens before granting access to file system resources. The vulnerability is further exacerbated by the application's lack of proper access control lists or authorization checks that should normally be enforced for remote file operations. The specific nature of the flaw allows for both read and write operations against arbitrary files, making it a particularly dangerous vulnerability for attackers seeking to compromise system integrity or extract sensitive information.
The operational impact of this vulnerability extends beyond simple unauthorized access to include potential system compromise and data loss scenarios. Remote attackers can leverage this vulnerability to perform cross-site request forgery attacks combined with DNS rebinding techniques, which allows them to bypass normal network security controls and gain access to systems that might otherwise be protected by firewalls or network segmentation. This type of attack is particularly effective against mobile devices or endpoints that have been configured to expose WebDAV services for remote file access. The vulnerability creates a persistent threat vector that can be exploited by attackers with minimal privileges, potentially leading to complete system compromise or unauthorized data access. Organizations using affected versions of BlackBerry Link may experience unauthorized data access, modification of critical files, or potential data exfiltration through this unauthenticated WebDAV interface.
The vulnerability aligns with several common weakness enumerations including CWE-287 which addresses improper authentication issues, and CWE-352 which covers cross-site request forgery vulnerabilities. From an attack framework perspective, this vulnerability maps to multiple ATT&CK techniques including T1190 for exploitation of remote services and T1071 for application layer protocol usage. The combination of WebDAV exposure without proper authentication and the use of DNS rebinding for CSRF attacks represents a sophisticated exploitation technique that demonstrates how multiple attack vectors can be combined to create more effective compromises. Organizations should implement immediate mitigations including updating to patched versions of BlackBerry Link, disabling unnecessary WebDAV services, and implementing proper network segmentation to prevent unauthorized access to potentially vulnerable endpoints. Additionally, monitoring for unauthorized WebDAV activity and implementing proper access controls for remote file access services can help detect and prevent exploitation attempts. The vulnerability serves as a reminder of the importance of proper authentication implementation and the risks associated with exposing administrative services without adequate security controls.