CVE-2022-3328 in snap-confine
Summary
by MITRE • 01/08/2024
Race condition in snap-confine's must_mkdir_and_open_with_perms()
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/03/2025
The vulnerability identified as CVE-2022-3328 represents a critical race condition flaw within the snap-confine utility of the snap package management system. This issue manifests in the must_mkdir_and_open_with_perms() function which is responsible for creating directories and opening files with specific permissions during the confinement process of snap applications. The race condition occurs when multiple processes attempt to create and access the same directory path simultaneously, creating a window of opportunity for malicious actors to exploit the timing gap between directory creation and permission setting operations.
The technical implementation of this vulnerability stems from improper synchronization mechanisms within the snap-confine utility's directory creation logic. When snap applications are launched, the system must ensure that all required directories exist with appropriate permissions before the application can access them. However, the must_mkdir_and_open_with_perms() function fails to properly lock or synchronize access to these directory creation operations, allowing concurrent processes to interfere with each other's operations. This flaw is particularly dangerous because it occurs during the critical initialization phase of snap applications, where the system is establishing security boundaries and access controls.
The operational impact of this race condition extends beyond simple permission issues and can potentially lead to privilege escalation attacks. An attacker who successfully exploits this vulnerability could manipulate the directory creation process to gain access to restricted areas of the filesystem or manipulate file permissions in ways that compromise the security model of the snap confinement system. This type of vulnerability directly violates the principle of least privilege that is fundamental to containerized and confined application environments, potentially allowing unauthorized access to sensitive system resources.
This vulnerability aligns with CWE-367, which describes the weakness of Time-of-Check to Time-of-Use (TOCTOU) race conditions, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves exploiting vulnerabilities to elevate privileges. The flaw represents a classic example of how improper handling of concurrent operations can create security holes in system utilities that are designed to enforce security policies. The impact is particularly severe in environments where snap packages are extensively used for application deployment, as this vulnerability could potentially affect the security boundaries of multiple applications running on the same system.
Mitigation strategies for CVE-2022-3328 should focus on implementing proper synchronization mechanisms within the snap-confine utility to prevent concurrent access to directory creation operations. System administrators should ensure that all snap packages are updated to versions that contain the patched must_mkdir_and_open_with_perms() function, which typically involves applying security updates from the distribution maintainers. Additionally, monitoring for suspicious directory creation patterns and implementing proper access control policies can help detect potential exploitation attempts. The fix generally involves introducing atomic operations or proper locking mechanisms that ensure directory creation and permission setting occur as a single, indivisible operation, preventing the race condition window that enables exploitation.