CVE-2007-0772 in Linux
Summary
by MITRE
The Linux kernel 2.6.13 and other versions before 2.6.20.1 allows remote attackers to cause a denial of service (oops) via a crafted NFSACL 2 ACCESS request that triggers a free of an incorrect pointer.
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Analysis
by VulDB Data Team • 07/16/2019
The vulnerability described in CVE-2007-0772 represents a critical memory management flaw within the Linux kernel's Network File System implementation that can be exploited to cause system-wide denial of service conditions. This issue affects kernel versions prior to 2.6.20.1 and specifically targets the NFSACL 2 ACCESS request handling mechanism, which is part of the broader NFS version 2 protocol implementation. The flaw occurs when the kernel processes a specially crafted NFSACL 2 ACCESS request that contains malformed pointer references, leading to improper memory deallocation operations.
The technical root cause of this vulnerability lies in the kernel's improper handling of memory pointers during NFSACL 2 ACCESS request processing, which results in a double free or use-after-free condition. When the kernel receives a malformed request containing incorrect pointer values, it attempts to free memory that either has already been freed or points to invalid memory locations. This memory corruption leads to kernel oops conditions, which are kernel-level panic events that cause the system to become unstable and potentially crash. The vulnerability is classified as a memory corruption issue that can be triggered remotely, making it particularly dangerous in networked environments where NFS services are exposed to untrusted clients.
The operational impact of this vulnerability extends beyond simple service disruption, as it can lead to complete system compromise and denial of service across networked systems. When exploited successfully, the vulnerability allows remote attackers to cause kernel panics that result in system crashes, forcing administrators to reboot affected systems and potentially losing unsaved data. The flaw affects systems running Linux kernel versions between 2.6.13 and 2.6.20.1, which were widely deployed in enterprise environments, making this vulnerability particularly impactful. The remote exploitation capability means that attackers do not need physical access to the system, enabling them to target vulnerable systems from anywhere on the network.
This vulnerability aligns with CWE-415, which describes improper handling of memory allocation and deallocation operations in kernel space, and demonstrates how improper pointer management can lead to system instability. The attack pattern corresponds to techniques found in the MITRE ATT&CK framework under the T1499 category, which covers network denial of service attacks that can be leveraged to compromise system availability. The flaw represents a classic example of how network protocol implementations can contain memory management errors that provide attackers with opportunities to disrupt system operations. Organizations should implement immediate patching strategies to address this vulnerability, as the kernel version 2.6.20.1 and later contain fixes for this memory corruption issue. Additionally, network segmentation and access controls should be implemented to limit exposure of NFS services to untrusted networks, reducing the attack surface for this and similar vulnerabilities.