CVE-2011-1832 in ecryptfs-utils
Summary
by MITRE
utils/mount.ecryptfs_private.c in ecryptfs-utils before 90 does not properly check mountpoint permissions, which allows local users to remove directories via a umount system call.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability described in CVE-2011-1832 resides within the ecryptfs-utils package version 90 and earlier, specifically in the utils/mount.ecryptfs_private.c component. This flaw represents a critical permission checking failure that undermines the security model of the encrypted filesystem implementation. The issue manifests when the system attempts to unmount encrypted filesystems, creating a scenario where local users can exploit improper mountpoint permission validation to remove directories through umount system calls.
This vulnerability operates at the kernel-level filesystem interface where the eCryptfs implementation fails to properly validate whether the requesting user possesses adequate permissions to perform directory removal operations during unmount processes. The flaw allows attackers to bypass normal access controls that should prevent unauthorized directory manipulation, creating a path for privilege escalation and potential data compromise. The technical implementation error occurs in the permission validation logic that should have enforced proper access controls before allowing directory removal operations.
The operational impact of this vulnerability extends beyond simple directory removal capabilities, as it enables local attackers to potentially manipulate the filesystem structure in ways that could lead to data loss, information disclosure, or further privilege escalation within the system. Attackers could exploit this weakness to remove critical system directories or manipulate encrypted filesystem structures, potentially leading to complete system compromise. The vulnerability affects systems that utilize eCryptfs for encrypted filesystem management and poses significant risk to environments where local user access is not properly restricted.
The root cause of this vulnerability aligns with CWE-284, which addresses improper access control mechanisms, and can be mapped to ATT&CK technique T1068, which involves exploiting local privileges to escalate access. The flaw demonstrates a classic case of inadequate input validation and permission checking, where the system fails to properly verify user credentials and access rights before executing potentially destructive operations. Security professionals should note that this vulnerability affects the fundamental integrity of the filesystem layer, making it particularly dangerous in multi-user environments.
Mitigation strategies for this vulnerability include immediate patching of ecryptfs-utils to version 90 or later, where the mountpoint permission checking has been properly implemented. System administrators should also implement additional monitoring for unauthorized umount operations and directory removal activities. The fix addresses the core permission validation issue by ensuring proper access control checks are performed before allowing directory manipulation during unmount processes. Organizations should conduct thorough security audits to identify systems running vulnerable versions of ecryptfs-utils and implement comprehensive access control policies to minimize potential exploitation risks.