CVE-2012-1097 in Linux
Summary
by MITRE • 01/25/2023
The regset (aka register set) feature in the Linux kernel before 3.2.10 does not properly handle the absence of .get and .set methods, which allows local users to cause a denial of service (NULL pointer dereference) or possibly have unspecified other impact via a (1) PTRACE_GETREGSET or (2) PTRACE_SETREGSET ptrace call.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2012-1097 resides within the Linux kernel's ptrace implementation, specifically affecting versions prior to 3.2.10. This issue manifests in the regset (register set) feature where the kernel fails to properly validate the presence of essential methods required for register manipulation. The ptrace system call serves as a critical debugging and process tracing mechanism in Unix-like operating systems, enabling one process to observe and control the execution of another. When applications or users attempt to manipulate register states through ptrace calls, the kernel must properly handle the underlying register set operations. The flaw occurs when the kernel encounters register set operations without the expected .get and .set method implementations, creating a dangerous condition where the system attempts to dereference null pointers during these operations.
The technical exploitation of this vulnerability involves leveraging the ptrace interface to issue either PTRACE_GETREGSET or PTRACE_SETREGSET commands against target processes. These commands are designed to retrieve or modify the register state of a traced process, but when the underlying register set implementation lacks proper method definitions, the kernel's handling code becomes susceptible to NULL pointer dereferences. This type of error represents a classic kernel memory corruption vulnerability that can lead to system instability. The vulnerability is categorized under CWE-476 as NULL pointer dereference, which is a fundamental programming error that can result in system crashes or potentially be exploited for privilege escalation. The impact extends beyond simple denial of service since the unspecified other impacts could include information disclosure or privilege escalation depending on the specific execution context and system configuration.
Operationally, this vulnerability presents significant risks to system stability and security integrity. Local users with minimal privileges can trigger the NULL pointer dereference by executing ptrace operations against processes they control or have access to. The denial of service aspect means that legitimate system processes may crash or become unresponsive, potentially disrupting critical system functions. The potential for unspecified other impacts suggests that under certain conditions, this vulnerability could be leveraged to gain elevated privileges or access sensitive system information. Attackers could potentially use this as a stepping stone for more sophisticated attacks, particularly in environments where process tracing capabilities are enabled or where users have the ability to execute ptrace operations. The vulnerability's impact is particularly concerning in multi-user environments or systems where debugging capabilities are frequently used, as it could be exploited to destabilize the entire system or compromise the integrity of running processes.
Mitigation strategies for CVE-2012-1097 primarily involve updating to kernel versions 3.2.10 or later, where the proper handling of missing register set methods has been implemented. System administrators should prioritize patching affected systems and verify that the kernel version is properly updated across all deployment environments. Additional protective measures include restricting ptrace capabilities through system security modules such as SELinux or AppArmor, limiting the ability of untrusted users to perform ptrace operations. The implementation of proper access controls and monitoring for ptrace usage can help detect potential exploitation attempts. Organizations should also consider implementing kernel hardening techniques and maintaining up-to-date security configurations to reduce the attack surface. From an operational security perspective, regular vulnerability assessments and kernel updates form the foundation of protecting against this type of memory corruption vulnerability, which aligns with ATT&CK technique T1068 for Local Privilege Escalation and T1499 for Endpoint Denial of Service. The vulnerability demonstrates the critical importance of proper input validation and error handling in kernel space code, where the consequences of programming errors can affect entire system operations and security boundaries.