CVE-2016-1585 in AppArmor
Summary
by MITRE
In all versions of AppArmor mount rules are accidentally widened when compiled.
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Analysis
by VulDB Data Team • 05/03/2025
The vulnerability identified as CVE-2016-1585 affects AppArmor, a mandatory access control system for Linux operating systems that implements path-based access controls. This flaw resides in the way AppArmor processes mount rules during the compilation phase of its security policies. The issue is particularly significant because it represents a fundamental weakness in the policy enforcement mechanism that could potentially undermine the security posture of systems relying on AppArmor for access control.
The technical flaw manifests when AppArmor compiles mount rules, causing the system to inadvertently expand the scope of permissions granted to processes. This occurs during the policy compilation process where the rules are parsed and converted into internal representations that govern how filesystem mounts are handled. The widening effect means that what should be restrictive mount rules become more permissive than originally intended, potentially allowing processes to access filesystems or mount points that they should not be permitted to access according to the administrator's security policies.
This vulnerability has substantial operational impact across various deployment scenarios where AppArmor is used to enforce security boundaries. Systems administrators who rely on AppArmor for container isolation, application sandboxing, or general system hardening may find that their security policies are effectively weakened without any indication of the problem. The flaw affects all versions of AppArmor, making it a widespread issue that requires immediate attention from organizations maintaining security policies based on mount rule enforcement. The widened permissions could potentially allow privilege escalation attacks or enable processes to access sensitive data that should be restricted by the security policy.
The vulnerability demonstrates a classic security issue related to improper access control enforcement and can be categorized under CWE-284, which deals with improper access control. From an operational security perspective, this flaw aligns with ATT&CK technique T1068, which involves exploiting privileges to gain elevated access. Organizations using AppArmor for security policy enforcement should consider this vulnerability as a critical threat to their security posture, particularly in environments where strict access control is required. The remediation typically involves applying patches or updates that fix the mount rule compilation logic to prevent the unintended widening of permissions. System administrators should also review existing AppArmor policies to identify any potential security gaps that may have been introduced by this vulnerability and consider implementing additional monitoring to detect unauthorized access patterns that might result from the expanded permissions.