CVE-2012-2291 in Avamar
Summary
by MITRE
EMC Avamar Client 4.x, 5.x, and 6.x on HP-UX and Mac OS X, and the EMC Avamar plugin 4.x, 5.x, and 6.x for Oracle, uses world-writable permissions for cache directories, which allows local users to gain privileges via an unspecified symlink attack.
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Analysis
by VulDB Data Team • 05/02/2018
The vulnerability identified as CVE-2012-2291 affects EMC Avamar Client versions 4.x through 6.x when deployed on HP-UX and Mac OS X operating systems, as well as the corresponding EMC Avamar plugin versions 4.x through 6.x for Oracle environments. This security flaw represents a critical privilege escalation vulnerability that stems from improper directory permissions within the application's caching mechanism. The issue manifests when cache directories are configured with world-writable permissions, creating an exploitable condition that local attackers can leverage to elevate their system privileges.
The technical flaw involves the creation of cache directories that are accessible and writable by all users on the system, combined with a symlink attack vector that allows malicious local users to manipulate the cache file structure. This configuration violates fundamental security principles by granting unnecessary write access to cache locations that should be restricted to the application's own execution context. The vulnerability specifically targets the interaction between the application's cache management and the operating system's permission model, where the symlink attack enables an attacker to place malicious files in locations that the application will subsequently process with elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data integrity violations. Local attackers with minimal privileges can exploit this weakness to inject malicious code into the cache directories, which may then be executed with the privileges of the Avamar client process. This creates a persistent threat vector that can be leveraged for unauthorized system access, data exfiltration, or further attack progression within the compromised environment. The vulnerability affects enterprise backup and recovery systems, potentially compromising the integrity of backup data and creating opportunities for attackers to manipulate backup processes.
Organizations should implement immediate mitigations including restricting cache directory permissions to prevent world-writable access and ensuring that all cache locations are properly secured with appropriate ownership and access controls. The fix involves modifying the application's cache directory configuration to enforce restrictive permissions and eliminate the symlink attack surface. Security teams should also conduct comprehensive audits of all Avamar installations to identify and remediate similar permission configurations across other application components. This vulnerability aligns with CWE-732, which addresses improper restriction of operations within a security domain, and represents a clear violation of the principle of least privilege. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068, which covers local privilege escalation through exploitation of system vulnerabilities. Organizations should also consider implementing monitoring solutions to detect unauthorized changes to cache directories and establish baseline configurations that prevent such insecure permission settings from being applied in the future.