CVE-2022-0247 in Fuchsia
Summary
by MITRE • 02/25/2022
An issue exists in Fuchsia where VMO data can be modified through access to copy-on-write snapshots. A local attacker could modify objects in the VMO that they do not have permission to. We recommend upgrading past commit d97c05d2301799ed585620a9c5c739d36e7b5d3d or any of the listed versions.
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Analysis
by VulDB Data Team • 02/28/2022
The vulnerability described in CVE-2022-0247 represents a critical security flaw within the Fuchsia operating system's virtual memory management subsystem. This issue specifically targets the Virtual Memory Object (VMO) implementation and exploits a weakness in the copy-on-write snapshot mechanism that governs memory sharing between processes. The vulnerability allows unauthorized modification of memory objects through improper access control enforcement within the VMO subsystem, creating a privilege escalation vector that undermines the fundamental memory protection mechanisms of the operating system.
The technical root cause of this vulnerability lies in the improper handling of copy-on-write snapshots within Fuchsia's memory management architecture. When a process attempts to access a VMO through a snapshot, the system should enforce strict access controls to prevent unauthorized modifications to memory regions that the accessing process does not have permission to alter. However, the flaw allows local attackers to bypass these access controls and modify objects within the VMO that they should not be able to access, effectively creating a path for privilege escalation. This behavior violates the core principles of memory isolation and access control that are fundamental to operating system security. The vulnerability manifests when the system fails to properly validate permissions during snapshot operations, allowing read-write access to memory regions that should remain protected.
The operational impact of this vulnerability extends beyond simple data modification, as it fundamentally compromises the integrity and confidentiality of the system's memory management. A local attacker with minimal privileges could leverage this vulnerability to modify critical system data structures, inject malicious code into protected memory regions, or manipulate the behavior of other processes running on the system. This creates a significant risk for systems where multiple users or processes share the same machine, as the vulnerability could be exploited to gain elevated privileges and potentially compromise the entire system. The impact is particularly severe in environments where Fuchsia is used for embedded systems, IoT devices, or other security-critical applications where memory isolation is paramount. The vulnerability's classification aligns with CWE-284 Access Control Issues, which specifically addresses improper access control mechanisms that allow unauthorized access to resources.
Mitigation strategies for this vulnerability primarily involve upgrading to the patched version of Fuchsia that addresses the specific VMO snapshot access control flaw. The recommended solution involves updating to a commit beyond d97c05d2301799ed585620a9c5c739d36e7b5d3d, which contains the necessary fixes to properly enforce access controls during copy-on-write operations. System administrators should also implement additional monitoring to detect unauthorized memory access patterns and consider implementing memory integrity checking mechanisms. The fix likely involves strengthening the permission validation logic within the VMO subsystem to ensure that snapshot operations properly enforce access control policies and prevent unauthorized modifications. Organizations should also conduct thorough security assessments to identify any potential exploitation of this vulnerability in their existing deployments and implement proper access control auditing to prevent similar issues from arising in other memory management components. This vulnerability demonstrates the importance of proper memory management implementation and highlights the critical nature of access control mechanisms in preventing privilege escalation attacks.