CVE-2009-0875 in OpenSolaris
Summary
by MITRE
Race condition in the Doors subsystem in the kernel in Sun Solaris 8 through 10, and OpenSolaris before snv_94, allows local users to cause a denial of service (process hang), or possibly bypass file permissions or gain kernel-context privileges, via vectors involving the time at which control is transferred from a caller to a door server.
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Analysis
by VulDB Data Team • 04/21/2025
The vulnerability described in CVE-2009-0875 represents a critical race condition within the Doors subsystem of Sun Solaris operating systems, affecting versions from Solaris 8 through 10 and OpenSolaris prior to snv_94. This flaw exists at the kernel level and specifically targets the interplay between caller processes and door servers during control transfer operations. The Doors subsystem serves as a mechanism for inter-process communication and provides a way for clients to invoke server routines in a controlled manner, making it a fundamental component of the operating system's architecture. The race condition occurs when timing-sensitive operations are not properly synchronized, creating a window where malicious or benign processes can exploit temporal inconsistencies in the kernel's handling of door operations.
The technical nature of this vulnerability stems from improper synchronization mechanisms within the kernel's door server implementation, where the sequence of operations during control transfer between caller and server creates exploitable timing gaps. When a process attempts to invoke a door server routine, the kernel must manage the transition from user space to kernel context while maintaining proper access controls and ensuring atomic operations. The race condition manifests when the timing of these transitions allows for manipulation of the control flow, potentially enabling attackers to manipulate the kernel's state during these critical moments. This flaw can be leveraged to either cause system instability through process hanging or more severely compromise system security by bypassing file permission checks or escalating privileges to kernel context.
The operational impact of CVE-2009-0875 extends beyond simple denial of service scenarios, as local users with minimal privileges can potentially exploit this vulnerability to achieve privilege escalation. The vulnerability aligns with CWE-362, which categorizes race conditions as a fundamental security weakness where concurrent operations can lead to unpredictable behavior and security breaches. Attackers can exploit this condition to manipulate the kernel's access control mechanisms, potentially allowing them to read restricted files, execute arbitrary code in kernel space, or otherwise compromise the integrity of the operating system. The implications are particularly severe given that the vulnerability exists in the kernel itself, meaning successful exploitation could provide attackers with complete system control, making this a high-severity issue for any organization running affected Solaris versions.
Mitigation strategies for this vulnerability require immediate patching of affected systems, as the race condition cannot be effectively addressed through configuration changes or workarounds. Organizations should prioritize updating their Solaris installations to versions that contain the appropriate kernel fixes for the Doors subsystem. System administrators should also implement monitoring for unusual process behavior or system hangs that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper synchronization mechanisms in kernel-level code and highlights the need for comprehensive security testing of system components that handle inter-process communication. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and defense evasion methods, as it can be used to bypass security controls and maintain persistent access to compromised systems. Regular security assessments and kernel integrity checks should be implemented to detect potential exploitation attempts and ensure that all systems remain protected against similar timing-based vulnerabilities.