CVE-2012-2137 in Linux
Summary
by MITRE
Buffer overflow in virt/kvm/irq_comm.c in the KVM subsystem in the Linux kernel before 3.2.24 allows local users to cause a denial of service (crash) and possibly execute arbitrary code via vectors related to Message Signaled Interrupts (MSI), irq routing entries, and an incorrect check by the setup_routing_entry function before invoking the kvm_set_irq function.
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Analysis
by VulDB Data Team • 03/25/2021
The vulnerability described in CVE-2012-2137 represents a critical buffer overflow flaw within the Kernel-based Virtual Machine (KVM) subsystem of the Linux kernel, specifically affecting versions prior to 3.2.24. This issue resides in the virt/kvm/irq_comm.c file and demonstrates a fundamental security weakness that can be exploited by local attackers to compromise system integrity and availability. The vulnerability manifests through improper handling of Message Signaled Interrupts (MSI) and interrupt routing entries, creating a scenario where malicious input can lead to system instability and potential privilege escalation.
The technical exploitation of this vulnerability occurs through the setup_routing_entry function which performs an incorrect validation check before calling the kvm_set_irq function. This flawed validation creates a condition where buffer boundaries are not properly enforced when processing interrupt routing information, allowing attackers to write beyond allocated memory regions. The flaw specifically affects how the kernel handles MSI interrupts and routing entries, enabling an attacker to manipulate the interrupt handling mechanism through carefully crafted inputs that exceed buffer limits. This type of vulnerability is classified under CWE-121 as a stack-based buffer overflow, where insufficient boundary checking permits memory corruption that can lead to unpredictable behavior.
The operational impact of CVE-2012-2137 extends beyond simple denial of service to potentially enable arbitrary code execution within the kernel context. Local users with access to the system can leverage this vulnerability to crash the kernel, causing system-wide denial of service, or more critically, execute malicious code with kernel-level privileges. The attack vector requires local system access but does not necessitate elevated privileges, making it particularly dangerous in multi-user environments where attackers might exploit this to escalate their privileges. The vulnerability's exploitation can result in complete system compromise, as successful exploitation allows attackers to gain full control over the kernel execution environment and potentially access all system resources.
Mitigation strategies for this vulnerability primarily involve upgrading to Linux kernel versions 3.2.24 or later, where the buffer overflow has been addressed through proper boundary checking and input validation. System administrators should also implement additional security measures such as restricting local user access where possible and monitoring for unusual interrupt handling patterns. The vulnerability aligns with ATT&CK technique T1068 which describes 'Local Privilege Escalation' through kernel exploits, and demonstrates the critical importance of maintaining up-to-date kernel versions to protect against known vulnerabilities. Organizations should conduct comprehensive vulnerability assessments to identify systems running affected kernel versions and prioritize patch deployment to prevent exploitation. Additionally, implementing kernel hardening techniques such as stack canaries and address space layout randomization can provide additional defense-in-depth measures against similar buffer overflow vulnerabilities.