CVE-2013-1797 in Linux
Summary
by MITRE
Use-after-free vulnerability in arch/x86/kvm/x86.c in the Linux kernel through 3.8.4 allows guest OS users to cause a denial of service (host OS memory corruption) or possibly have unspecified other impact via a crafted application that triggers use of a guest physical address (GPA) in (1) movable or (2) removable memory during an MSR_KVM_SYSTEM_TIME kvm_set_msr_common operation.
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Analysis
by VulDB Data Team • 05/06/2021
The CVE-2013-1797 vulnerability represents a critical use-after-free condition within the Linux kernel's KVM virtualization subsystem, specifically affecting versions through 3.8.4. This flaw exists in the x86 architecture implementation of KVM virtualization, where guest operating systems can exploit a memory management inconsistency to potentially corrupt host system memory. The vulnerability manifests during specific MSR_KVM_SYSTEM_TIME operations when the kernel processes guest physical addresses that have been marked as movable or removable, creating a scenario where freed memory locations are accessed beyond their intended lifecycle. This particular flaw falls under the CWE-416 use-after-free vulnerability category, which is classified as a memory safety issue that can lead to unpredictable behavior and system instability.
The technical execution of this vulnerability requires a guest OS user to craft a specific application that triggers the problematic code path during KVM system time management operations. When the kernel encounters a guest physical address that has been marked as movable or removable during the kvm_set_msr_common operation, it fails to properly validate memory state before accessing the address. This improper validation creates a window where memory that should have been freed is still referenced, allowing for potential memory corruption or arbitrary code execution. The vulnerability is particularly dangerous because it operates at the hypervisor level, where guest users can directly influence host system memory management through carefully constructed virtual machine operations. The attack vector specifically targets the kernel's memory management subsystem during virtual machine system time synchronization, where the kernel attempts to map guest physical addresses into host memory space.
The operational impact of CVE-2013-1797 extends beyond simple denial of service to potentially enable more severe compromise scenarios. While the primary effect is host OS memory corruption leading to system instability, the vulnerability could theoretically be exploited to escalate privileges or execute arbitrary code within the host system. The use-after-free condition creates opportunities for attackers to manipulate memory layout and potentially overwrite critical kernel data structures, which aligns with ATT&CK technique T1068 for locally executed code and T1059 for command and scripting interpreter usage. When exploited successfully, this vulnerability can cause complete system crashes or allow malicious guest users to gain unauthorized access to host resources, making it particularly dangerous in multi-tenant virtualized environments where isolation is critical for security. The vulnerability's impact is amplified in cloud computing environments where multiple untrusted guests share the same physical host infrastructure.
Mitigation strategies for CVE-2013-1797 focus primarily on kernel updates and virtualization environment hardening. The most effective immediate solution is upgrading to Linux kernel versions 3.8.5 or later, where the vulnerability has been patched through proper memory state validation during MSR_KVM_SYSTEM_TIME operations. System administrators should also implement strict virtualization policies that limit guest OS capabilities and monitor for unusual memory access patterns. Additional mitigations include disabling unnecessary KVM features, implementing proper memory management policies for virtual machines, and maintaining comprehensive monitoring of system logs for signs of memory corruption. The vulnerability highlights the importance of proper memory management in hypervisor code and demonstrates why virtualization security requires rigorous testing and validation of memory handling operations. Organizations should also consider implementing network segmentation and access controls to limit potential exploitation impact, while maintaining regular security assessments of their virtualized environments to identify similar memory safety issues.