CVE-2008-1057 in OpenBSD
Summary
by MITRE
The ip6_check_rh0hdr function in netinet6/ip6_input.c in OpenBSD 4.2 allows attackers to cause a denial of service (panic) via malformed IPv6 routing headers.
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Analysis
by VulDB Data Team • 09/19/2018
The vulnerability identified as CVE-2008-1057 represents a critical denial of service flaw in OpenBSD 4.2's IPv6 implementation. This issue specifically targets the ip6_check_rh0hdr function located within the netinet6/ip6_input.c source file, which processes incoming IPv6 packets containing routing headers. The flaw manifests when the system encounters malformed IPv6 routing headers that do not conform to the expected protocol specifications, causing the kernel to panic and terminate the network stack functionality. This vulnerability directly impacts the availability of network services by allowing remote attackers to disrupt IPv6 packet processing without requiring authentication or elevated privileges.
The technical nature of this vulnerability stems from insufficient input validation within the IPv6 routing header processing logic. When the ip6_check_rh0hdr function receives malformed routing headers, it fails to properly validate the header structure and length parameters before proceeding with packet processing. This inadequate validation leads to potential buffer overflows, invalid memory accesses, or arithmetic underflows that trigger kernel panic conditions. The vulnerability operates at the network protocol level, specifically within the IPv6 input processing pipeline where routing headers are examined for proper format and content. According to CWE classification, this represents a weakness in the validation of input data, specifically CWE-129, which involves insufficient checking of the length or size of input data. The flaw demonstrates characteristics of CWE-121, buffer overflow conditions, and CWE-125, out-of-bounds read, as the function does not properly bounds-check header fields before accessing memory regions.
The operational impact of CVE-2008-1057 extends beyond simple service disruption to potentially compromise entire network infrastructure. When exploited successfully, the vulnerability causes a kernel panic that results in immediate system unresponsiveness and requires manual intervention to restore normal operations. This makes the vulnerability particularly dangerous in environments where continuous network availability is critical, such as enterprise data centers, network infrastructure devices, or any system relying on IPv6 connectivity. The attack vector is remote and requires no authentication, making it highly exploitable in networked environments where IPv6 traffic flows are present. The vulnerability can be leveraged by attackers to perform distributed denial of service attacks against targeted systems, potentially causing cascading failures in network services that depend on IPv6 connectivity. From an attacker tactics perspective, this vulnerability aligns with ATT&CK technique T1499.004, which involves network disruption through service availability attacks, and T1595.001, which encompasses reconnaissance activities targeting network infrastructure.
Mitigation strategies for this vulnerability require immediate system updates and patches provided by OpenBSD developers. The most effective solution involves upgrading to OpenBSD versions that contain the patched ip6_check_rh0hdr function with proper input validation mechanisms. Network administrators should implement defensive measures such as disabling IPv6 routing header processing when not required, utilizing firewalls to filter malformed IPv6 packets, and monitoring network traffic for suspicious routing header patterns. The implementation of proper input validation and bounds checking in kernel space code serves as the fundamental defense against this class of vulnerability. Additionally, system administrators should consider implementing network segmentation and access controls to limit exposure to potential attackers. The vulnerability highlights the importance of rigorous security testing for kernel-level network protocol implementations and underscores the necessity of maintaining up-to-date security patches. Organizations should also establish incident response procedures specifically addressing kernel panic conditions and ensure adequate backup and recovery mechanisms are in place to minimize downtime during exploitation attempts.