CVE-2007-1365 in OpenBSD
Summary
by MITRE
Buffer overflow in kern/uipc_mbuf2.c in OpenBSD 3.9 and 4.0 allows remote attackers to execute arbitrary code via fragmented IPv6 packets due to "incorrect mbuf handling for ICMP6 packets." NOTE: this was originally reported as a denial of service.
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Analysis
by VulDB Data Team • 02/28/2025
The vulnerability described in CVE-2007-1365 represents a critical buffer overflow flaw within the OpenBSD operating system kernel, specifically in the network stack implementation. This issue affects versions 3.9 and 4.0 of the OpenBSD operating system, where the problem manifests in the kern/uipc_mbuf2.c source file. The vulnerability stems from improper handling of mbuf structures when processing ICMP6 packets, which are integral components of the IPv6 protocol suite used for error reporting and network diagnostics.
The technical root cause of this vulnerability lies in the incorrect management of mbuf (memory buffer) structures during the processing of fragmented IPv6 packets. When the kernel receives specially crafted fragmented ICMP6 packets, it fails to properly validate the boundaries of these packets against the allocated buffer space. This mbuf handling error creates a condition where an attacker can overflow the allocated memory buffer, potentially allowing arbitrary code execution with kernel privileges. The vulnerability operates through the network stack's packet reassembly mechanism, where fragmented packets are processed and reassembled before being passed to the appropriate protocol handlers.
The operational impact of this vulnerability is severe as it enables remote code execution without requiring authentication or local access. An attacker positioned on the network can exploit this flaw by sending maliciously crafted fragmented IPv6 packets to a vulnerable OpenBSD system. The buffer overflow can be leveraged to overwrite critical kernel memory locations, potentially leading to complete system compromise. This makes the vulnerability particularly dangerous in networked environments where OpenBSD systems may be exposed to untrusted network traffic. The original classification as a denial of service vulnerability was misleading since the actual exploit capability extends far beyond simple service disruption to include full system compromise.
This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and more specifically relates to CWE-787, representing out-of-bounds write vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for command and scripting interpreter and T1566 for credential access through network infiltration. The exploit requires no special privileges to initiate but can result in complete system compromise, making it a high-value target for attackers seeking persistent access to network infrastructure. Organizations running affected OpenBSD versions should immediately apply security patches or implement network segmentation measures to prevent exploitation.
The flaw demonstrates the critical importance of proper buffer management in kernel code and highlights the risks associated with complex network protocol handling. Memory management errors in kernel space can have catastrophic consequences, as they provide direct pathways to system compromise. This vulnerability underscores the necessity for rigorous code review processes, particularly for network stack implementations, and emphasizes the importance of maintaining up-to-date security patches in production environments. The issue also demonstrates how seemingly minor protocol handling flaws can result in major security implications, reinforcing the principle that network security must be considered at every layer of system architecture.