Source: cve@mitre.org
The Linux kernel before 2.6.11 on the Itanium IA64 platform has certain "ptrace corner cases" that allow local users to cause a denial of service (crash) via crafted syscalls, possibly related to MCA/INIT, a different vulnerability than CVE-2005-1761.
Local users on Itanium IA64 systems running Linux kernels before 2.6.11 can trigger a denial-of-service (DoS) condition, leading to system crashes. This vulnerability exploits ptrace corner cases within the kernel's syscall handling, allowing attackers to disrupt system availability by crafting malicious system calls.
Step 1: User Privilege: An attacker must have local user access to the vulnerable system. Step 2: Crafting Malicious Syscalls: The attacker crafts a series of system calls, specifically designed to exploit the ptrace corner cases within the kernel. Step 3: Syscall Execution: The crafted system calls are executed by the attacker's process. Step 4: Kernel Interaction: The system calls interact with the kernel's ptrace implementation, potentially triggering interactions with the MCA/INIT subsystems. Step 5: Triggering the Vulnerability: The crafted system calls, due to the vulnerability, cause memory corruption, incorrect register values, or other undefined behavior within the kernel. Step 6: Denial of Service: The memory corruption or undefined behavior leads to a kernel panic, resulting in a system crash and denial of service.
The vulnerability stems from flawed handling of ptrace system calls on the Itanium IA64 architecture, specifically within the kernel's interaction with the Machine Check Architecture (MCA) and Initialization (INIT) mechanisms. The root cause lies in improper validation and synchronization of data structures and registers during the processing of crafted system calls. This leads to memory corruption or undefined behavior, ultimately resulting in a kernel panic and system crash. The specific flaw involves mishandling of certain corner cases related to the interaction between ptrace and the MCA/INIT subsystems, potentially leading to incorrect register values or memory access violations. The lack of robust error checking and proper synchronization allows for the exploitation of these corner cases.
Due to the age and specific architecture, it's unlikely this vulnerability is actively targeted by sophisticated APTs. However, any threat actor with access to legacy systems could potentially exploit this vulnerability. The risk is primarily from internal threats or attackers targeting specific, vulnerable environments. Not listed on CISA KEV.
Monitor system logs for unexpected kernel panics or crashes, especially on Itanium IA64 systems.
Analyze system call traces (using tools like strace) for suspicious sequences of system calls, particularly those involving ptrace.
Examine core dumps (if available) for evidence of memory corruption or stack traces indicating the vulnerability.
Implement intrusion detection rules to flag unusual system call patterns on Itanium IA64 systems.
Monitor for MCA/INIT related errors in system logs.
Upgrade the Linux kernel to version 2.6.11 or later.
Apply security patches provided by the Linux distribution vendor.
Implement strict access controls to limit local user privileges.
Regularly audit system logs for suspicious activity.
Consider migrating away from Itanium IA64 systems if feasible, due to the age and end-of-life status of the architecture.