CVE-2013-4324 in spice-gtk
Summary
by MITRE
spice-gtk 0.14, and possibly other versions, invokes the polkit authority using the insecure polkit_unix_process_new API function, which allows local users to bypass intended access restrictions by leveraging a PolkitUnixProcess PolkitSubject race condition via a (1) setuid process or (2) pkexec process, a related issue to CVE-2013-4288.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2013-4324 affects the spice-gtk library version 0.14 and potentially other versions, presenting a significant security flaw in the way the library interacts with the PolicyKit authorization system. This issue stems from the improper invocation of the polkit_unix_process_new API function, which creates a critical race condition that undermines the intended security controls. The vulnerability specifically impacts systems where spice-gtk is used for remote desktop functionality, making it particularly concerning for enterprise environments that rely on virtualization and remote access solutions.
The technical flaw manifests through a race condition in the PolkitUnixProcess PolkitSubject implementation, where the spice-gtk library fails to properly validate process ownership when establishing authorization contexts. This race condition occurs during the creation of PolkitUnixProcess objects, allowing malicious local users to exploit the timing window between process creation and authorization validation. The vulnerability can be triggered through two primary vectors: setuid processes and pkexec processes, both of which represent common mechanisms for privilege escalation in Unix-like operating systems. When exploited, the race condition enables attackers to bypass access restrictions that should normally prevent unauthorized operations, effectively undermining the security model that PolicyKit is designed to enforce.
The operational impact of CVE-2013-4324 extends beyond simple privilege escalation, as it represents a fundamental breakdown in the authorization mechanism that protects system resources. Local users who can manipulate process creation timing or execute code in the context of setuid applications can leverage this vulnerability to gain elevated privileges without proper authentication. This creates a pathway for attackers to perform actions that should be restricted to authorized users only, potentially leading to complete system compromise. The vulnerability is particularly dangerous in multi-user environments where users may have legitimate access to the spice-gtk library but lack appropriate authorization for sensitive system operations. The related nature of this issue to CVE-2013-4288 indicates a broader pattern of weaknesses in how PolicyKit subjects are handled within the broader ecosystem of desktop and virtualization software.
Mitigation strategies for CVE-2013-4324 should focus on immediate patching of affected spice-gtk versions, with particular attention to updating to versions that properly handle the PolkitUnixProcess object creation without race conditions. System administrators should also implement additional monitoring for unusual process creation patterns that might indicate exploitation attempts, particularly around setuid binaries and pkexec usage. The vulnerability aligns with CWE-362, which describes a race condition that allows concurrent processes to access shared resources in an unsafe manner, and relates to ATT&CK technique T1068, which covers privilege escalation through local exploitation. Organizations should also consider implementing stricter controls around setuid binaries and regular security audits of desktop environments to prevent similar issues from arising in other components of their software stack. The fix typically involves proper validation of process ownership and ensuring that authorization decisions are made before process execution continues, preventing the race condition that enables the bypass of access restrictions.