CVE-2011-1836 in ecryptfs-utils
Summary
by MITRE
utils/ecryptfs-recover-private in ecryptfs-utils before 90 does not establish a subdirectory with safe permissions, which might allow local users to bypass intended access restrictions via standard filesystem operations during the recovery process.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability identified as CVE-2011-1836 resides within the ecryptfs-utils package, specifically in the utils/ecryptfs-recover-private utility. This flaw affects versions prior to 90 and represents a significant security weakness in the encrypted filesystem recovery process. The issue stems from improper permission handling during the recovery operation, creating an avenue for local attackers to circumvent intended access controls that should protect encrypted data.
The technical implementation flaw occurs when the ecryptfs-recover-private utility processes encrypted filesystem recovery operations. During this process, the utility fails to properly establish a subdirectory with appropriate security permissions, leaving the recovery environment in a state where local users can manipulate filesystem operations to gain unauthorized access. This represents a classic case of insufficient privilege separation and inadequate access control enforcement during sensitive operations.
The operational impact of this vulnerability is substantial as it allows local users to bypass access restrictions that are fundamental to the security model of encrypted filesystems. Attackers can exploit this weakness to recover encrypted data without proper authentication, effectively undermining the entire encryption scheme. The vulnerability particularly affects systems where ecryptfs is used for file-level encryption, potentially exposing sensitive data to unauthorized access. This weakness is particularly concerning because it operates at the filesystem level during recovery operations when users expect heightened security controls.
From a cybersecurity perspective, this vulnerability maps to CWE-276, which addresses improper file permissions, and aligns with ATT&CK technique T1552.001 for unsecured credentials. The flaw represents a privilege escalation vector that could enable attackers to access encrypted data that should remain protected. The recovery process, which should be a secure operation, becomes a potential attack surface due to the improper handling of directory permissions. Organizations using ecryptfs for data protection should consider this vulnerability as a critical risk requiring immediate remediation.
The recommended mitigation strategy involves upgrading to ecryptfs-utils version 90 or later, which contains the necessary fixes for proper permission handling during recovery operations. System administrators should also implement additional monitoring to detect unauthorized access attempts during encryption recovery processes. Regular security audits should verify that recovery directories maintain appropriate permissions and that no unauthorized modifications occur during sensitive operations. Organizations should also consider implementing additional access controls and logging mechanisms to detect potential exploitation attempts. The fix addresses the core issue by ensuring that subdirectories are properly established with appropriate security permissions during the recovery process, preventing local users from manipulating filesystem operations to bypass intended access restrictions.