CVE-2009-1388 in Linux
Summary
by MITRE
The ptrace_start function in kernel/ptrace.c in the Linux kernel 2.6.18 does not properly handle simultaneous execution of the do_coredump function, which allows local users to cause a denial of service (deadlock) via vectors involving the ptrace system call and a coredumping thread.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/12/2021
The vulnerability identified as CVE-2009-1388 resides within the Linux kernel's ptrace functionality, specifically in the ptrace_start function located in kernel/ptrace.c at version 2.6.18. This flaw represents a classic race condition scenario that exploits the improper handling of concurrent execution paths within the kernel's memory management subsystem. The vulnerability manifests when multiple threads attempt to execute the do_coredump function simultaneously while being controlled through ptrace system calls, creating a scenario where kernel resources become indefinitely blocked.
The technical implementation of this vulnerability stems from insufficient synchronization mechanisms within the kernel's ptrace subsystem. When a process attempts to attach to another process using ptrace while that target process is in the midst of generating a core dump, the kernel's locking mechanisms fail to prevent concurrent access to shared resources. This creates a deadlock condition where the ptrace operation waits indefinitely for resources that are held by the coredump process, while the coredump process itself waits for ptrace resources that are blocked by the ptrace operation. The flaw operates at the kernel level and requires local user privileges to exploit, making it a local privilege escalation vulnerability that can result in system instability.
The operational impact of this vulnerability extends beyond simple denial of service to potentially compromise system availability and stability. Attackers can leverage this weakness to create persistent denial of service conditions that may require system reboot to resolve, effectively rendering the affected system unusable until manual intervention occurs. The vulnerability affects systems running Linux kernel versions up to and including 2.6.18, making it particularly concerning for enterprise environments where kernel updates may be delayed or managed through complex deployment cycles. This type of deadlock condition can be particularly challenging to diagnose and resolve as it typically manifests as system unresponsiveness rather than clear error messages.
From a cybersecurity perspective, this vulnerability aligns with CWE-362, which describes race conditions in kernel-level operations, and demonstrates characteristics consistent with ATT&CK technique T1499.001, which involves the exploitation of system resource consumption through denial of service attacks. The vulnerability's exploitation requires minimal privileges and can be automated, making it attractive to threat actors seeking to disrupt system availability. Mitigation strategies include immediate kernel updates to versions that address the synchronization issues in ptrace operations, implementing proper kernel locking mechanisms, and applying security patches that resolve the race condition between ptrace and coredump functions. Organizations should also consider implementing process monitoring to detect unusual ptrace activity patterns that may indicate exploitation attempts, as well as maintaining robust backup and recovery procedures to minimize the impact of potential exploitation events.