CVE-2015-5231 in CRIU
Summary
by MITRE
The service daemon in CRIU does not properly restrict access to non-dumpable processes, which allows local users to obtain sensitive information via (1) process dumps or (2) ptrace access.
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Analysis
by VulDB Data Team • 08/23/2022
The vulnerability identified as CVE-2015-5231 resides within the checkpoint and restore infrastructure in CRIU (Checkpoint/Restore In Userspace) service daemon, a critical component for system-level process management and virtualization. This flaw represents a significant security weakness that undermines the fundamental principle of process isolation and privilege separation that modern operating systems rely upon for maintaining system integrity. The issue manifests when the service daemon fails to properly enforce access controls for processes marked as non-dumpable, which are typically those that contain sensitive information or operate with elevated privileges. This failure creates an exploitable condition that allows local attackers to bypass intended security boundaries and access information that should remain protected.
The technical implementation of this vulnerability stems from improper access control mechanisms within the CRIU service daemon that govern how it interacts with process memory and debugging interfaces. When processes are marked as non-dumpable, the operating system typically prevents unauthorized access to their memory space through various mechanisms including ptrace restrictions and memory dumping limitations. However, the CRIU daemon fails to properly enforce these restrictions, allowing local users to leverage either process dump functionality or ptrace debugging capabilities to extract sensitive information from processes that should be protected. This flaw specifically affects the daemon's handling of process access permissions during checkpoint and restore operations, where it should be enforcing strict access controls but instead permits unauthorized access to sensitive process memory.
The operational impact of CVE-2015-5231 extends beyond simple information disclosure to potentially enable more sophisticated attacks that could compromise system security. Local users who exploit this vulnerability can gain access to sensitive data that might include authentication tokens, cryptographic keys, personal information, or other confidential data stored within protected processes. The vulnerability is particularly concerning because it operates at the system level where privilege separation is most critical, and it can be exploited without requiring network access or elevated privileges beyond local user access. Attackers can leverage this flaw to perform reconnaissance activities, gather intelligence for further attacks, or directly extract sensitive information from running processes that would normally be protected by the system's security model.
Mitigation strategies for CVE-2015-5231 should focus on implementing proper access control enforcement within the CRIU service daemon and ensuring that all process access operations are properly validated against security policies. System administrators should ensure that CRIU is updated to versions that address this vulnerability, as the fix typically involves strengthening access control checks and properly enforcing non-dumpable process restrictions. Additionally, implementing principle of least privilege configurations, restricting local user access to critical system components, and monitoring for unauthorized access attempts can help reduce the attack surface. From a compliance perspective, this vulnerability aligns with CWE-284 which addresses improper access control, and could be categorized under ATT&CK technique T1056 for input injection and privilege escalation. Organizations should also consider implementing process monitoring and anomaly detection systems that can identify unauthorized ptrace operations or memory dumping activities that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper privilege separation in system-level tools and highlights the need for comprehensive security testing of critical infrastructure components that handle process memory access and system-level operations.