CVE-2012-3484 in Tunnelblick
Summary
by MITRE
Tunnelblick 3.3beta20 and earlier relies on a test for specific ownership and permissions to determine whether a program can be safely executed, which allows local users to bypass intended access restrictions and gain privileges via a (1) user-mountable image or (2) network share.
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Analysis
by VulDB Data Team • 02/20/2019
The vulnerability identified as CVE-2012-3484 affects Tunnelblick versions 3.3beta20 and earlier, presenting a critical security flaw in the application's privilege escalation mechanism. This issue stems from an inadequate security model that relies on simplistic ownership and permission checks to validate program execution safety. The vulnerability specifically targets the software's handling of user-mountable images and network shares, creating exploitable pathways for local attackers to bypass intended access controls. The flaw represents a fundamental weakness in the application's security architecture where file system permissions are insufficient to prevent unauthorized execution of potentially malicious code.
The technical implementation of this vulnerability occurs through a flawed access control mechanism that fails to properly validate the integrity and authenticity of files within user-mountable images or network shares. When Tunnelblick processes these file systems, it performs only basic ownership and permission checks rather than comprehensive security validation. This approach creates a privilege escalation vector because an attacker with local access can manipulate file permissions or ownership in ways that circumvent the application's intended security boundaries. The vulnerability operates at the system level where the application's security model assumes that proper file ownership and permissions guarantee safe execution, which proves to be a critical oversight in the security design.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and unauthorized access to sensitive resources. Local users who exploit this vulnerability can gain elevated privileges that would normally be restricted, potentially allowing them to access restricted system resources, modify critical files, or execute arbitrary code with higher privileges. The attack surface is particularly concerning because it leverages common system constructs like user-mountable images and network shares, which are frequently used in enterprise and personal computing environments. This vulnerability can be exploited without requiring network access or specialized tools, making it particularly dangerous in environments where local access is possible.
Mitigation strategies for CVE-2012-3484 should focus on immediate software updates to versions that address the flawed access control implementation. Organizations should ensure that all affected systems are updated to the latest stable version of Tunnelblick that includes proper security validation mechanisms. Additionally, system administrators should implement enhanced monitoring of file system changes and access patterns to detect potential exploitation attempts. The vulnerability aligns with CWE-284, which addresses improper access control, and relates to ATT&CK technique T1068, privilege escalation through local exploitation. Security measures should include restricting local file system access where possible and implementing more robust file validation mechanisms that go beyond simple ownership checks. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of local privilege escalation attacks.