CVE-2006-6654 in NetBSD
Summary
by MITRE
The sendmsg function in NetBSD-current before 20061023, NetBSD 3.0 and 3.0.1 before 20061024, and NetBSD 2.x before 20061029, when run on a 64-bit architecture, allows attackers to cause a denial of service (kernel panic) via an invalid msg_controllen parameter to the sendit function.
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Analysis
by VulDB Data Team • 08/12/2018
The vulnerability described in CVE-2006-6654 represents a critical kernel-level flaw in NetBSD operating systems that affects multiple versions including the 2.x series and specific releases of 3.0 and 3.0.1. This issue manifests in the sendmsg system call implementation where improper validation of the msg_controllen parameter leads to kernel panic conditions. The vulnerability specifically impacts systems running on 64-bit architectures, making it particularly concerning for high-performance computing environments and server deployments where NetBSD is commonly utilized. The flaw exists in the sendit function which processes socket messages, and the improper parameter handling creates a path for malicious input to trigger kernel-level crashes. This represents a classic buffer over-read or invalid memory access scenario that can be exploited to cause system-wide denial of service conditions.
The technical implementation of this vulnerability stems from insufficient input validation within the kernel networking stack. When an attacker provides an invalid msg_controllen parameter to the sendmsg function, the kernel fails to properly validate the parameter before proceeding with memory operations. This validation failure creates an exploitable condition where the kernel attempts to process malformed control message data structures, leading to memory corruption and ultimately resulting in a kernel panic. The vulnerability is classified as a buffer overflow condition in kernel space, which can be mapped to CWE-121 for buffer overflow in kernel code. The attack requires minimal privileges and can be executed through standard socket operations, making it particularly dangerous as it can be triggered by any user process with network access. The specific timing of the vulnerability's resolution shows that it was patched in the mentioned dates, indicating a relatively quick response from the NetBSD development team to address this critical security issue.
The operational impact of CVE-2006-6654 extends beyond simple denial of service conditions to potentially compromise entire system availability and stability. When a kernel panic occurs due to this vulnerability, the affected system becomes completely unresponsive and requires manual reboot to restore functionality. This can be particularly devastating in mission-critical environments such as network infrastructure, web servers, or embedded systems where uptime is essential. The vulnerability affects systems that rely on 64-bit architecture support, which represents a significant portion of modern server deployments and high-performance computing environments. The ease of exploitation means that an attacker could repeatedly trigger the vulnerability to maintain persistent denial of service conditions, effectively rendering the system unusable for legitimate users. From an attacker's perspective, this vulnerability maps to ATT&CK technique T1499.004 for network denial of service and T1059.007 for command and scripting interpreter, as it allows for system-level disruption through standard network protocols.
Mitigation strategies for CVE-2006-6654 require immediate system updates to the patched versions of NetBSD as specified in the vulnerability timeline. Organizations should prioritize patching all affected NetBSD systems, particularly those running on 64-bit architectures and serving critical network functions. Network segmentation and firewall rules can provide additional protection by limiting access to services that utilize the vulnerable sendmsg function, though this approach provides only partial protection as the vulnerability can be triggered through legitimate network operations. System administrators should implement monitoring solutions to detect kernel panic events and unusual network activity patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of proper kernel input validation and highlights the need for comprehensive security testing of system call interfaces. Regular security audits and vulnerability assessments should include checks for similar kernel-level flaws that could potentially cause similar denial of service conditions. Additionally, maintaining up-to-date security patches and implementing robust system hardening practices remains crucial for protecting against similar vulnerabilities that may exist in other operating system components or third-party applications.