CVE-2016-1879 in FreeBSD
Summary
by MITRE
The Stream Control Transmission Protocol (SCTP) module in FreeBSD 9.3 before p33, 10.1 before p26, and 10.2 before p9, when the kernel is configured for IPv6, allows remote attackers to cause a denial of service (assertion failure or NULL pointer dereference and kernel panic) via a crafted ICMPv6 packet.
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Analysis
by VulDB Data Team • 07/05/2024
The Stream Control Transmission Protocol (SCTP) implementation in FreeBSD operating systems contains a critical vulnerability that affects multiple versions including 9.3 before patch level 33, 10.1 before patch level 26, and 10.2 before patch level 9. This vulnerability specifically manifests when the kernel is configured to support IPv6 networking protocols and can be exploited by remote attackers to induce system-wide denial of service conditions. The flaw resides within the kernel-level SCTP module's handling of ICMPv6 packets, which are essential for IPv6 network operations including error reporting and network configuration. When properly crafted malicious ICMPv6 packets are received by an affected FreeBSD system, they trigger an assertion failure or null pointer dereference within the kernel's SCTP processing code, ultimately leading to a kernel panic that completely crashes the system.
The technical nature of this vulnerability stems from inadequate input validation and error handling within the SCTP kernel module's ICMPv6 packet processing logic. According to CWE classification, this represents a weakness in input validation where the system fails to properly validate the structure and content of incoming ICMPv6 packets before processing them within the SCTP context. The vulnerability manifests through a classic null pointer dereference scenario where the kernel attempts to access memory locations that have not been properly initialized or allocated, resulting in system instability. This type of flaw falls under the ATT&CK technique T1499.004 for Network Denial of Service, where adversaries exploit weaknesses in network protocol implementations to disrupt system availability. The kernel panic that results from this vulnerability represents a critical failure state where the operating system cannot continue normal operations and must be restarted.
The operational impact of CVE-2016-1879 extends beyond simple service disruption as it can affect any FreeBSD system running with IPv6 support and active SCTP functionality. Attackers can remotely exploit this vulnerability without requiring authentication or elevated privileges, making it particularly dangerous in networked environments where systems may be exposed to untrusted network traffic. The vulnerability affects systems that have SCTP configured as part of their network stack, which includes various server applications and network infrastructure components that rely on SCTP for reliable message transfer. The consequences include complete system crashes, requiring manual intervention for system recovery, potential data loss, and service interruptions that can affect business continuity. Organizations running FreeBSD systems with IPv6 enabled and SCTP support should consider this vulnerability particularly critical as it allows for remote system compromise through simple packet injection attacks.
Mitigation strategies for this vulnerability primarily involve applying the appropriate security patches released by FreeBSD for the affected versions. System administrators should immediately update to FreeBSD versions that include the fix for this specific SCTP implementation flaw, particularly ensuring that patch levels p33, p26, and p9 are applied for the respective affected versions. Network administrators may also consider implementing firewall rules to filter or drop suspicious ICMPv6 traffic, although this approach provides only partial protection as the vulnerability can be triggered by legitimate network operations. The fundamental solution requires proper kernel-level input validation and error handling within the SCTP implementation to prevent malformed packets from causing memory access violations. Additionally, organizations should monitor their systems for any signs of exploitation attempts and maintain robust backup and recovery procedures to minimize downtime in case of successful attacks. This vulnerability highlights the importance of thorough kernel security testing and the critical need for maintaining up-to-date system patches to protect against known protocol implementation flaws.