CVE-2013-2206 in Linux
Summary
by MITRE
The sctp_sf_do_5_2_4_dupcook function in net/sctp/sm_statefuns.c in the SCTP implementation in the Linux kernel before 3.8.5 does not properly handle associations during the processing of a duplicate COOKIE ECHO chunk, which allows remote attackers to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact via crafted SCTP traffic.
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Analysis
by VulDB Data Team • 05/17/2021
The vulnerability identified as CVE-2013-2206 represents a critical flaw in the Stream Control Transmission Protocol implementation within the Linux kernel's networking stack. This issue specifically affects the sctp_sf_do_5_2_4_dupcook function located in net/sctp/sm_statefuns.c, which governs the state machine operations during SCTP association processing. The vulnerability manifests when the kernel receives crafted SCTP traffic containing duplicate COOKIE ECHO chunks, creating a scenario where the system fails to properly validate association states before attempting to process these chunks.
The technical root cause of this vulnerability stems from inadequate input validation and state management within the SCTP state machine. When duplicate COOKIE ECHO chunks are received, the function fails to properly check whether the association context remains valid, leading to a NULL pointer dereference condition. This occurs because the SCTP implementation assumes certain association parameters remain initialized while processing duplicate chunks, but in malformed traffic scenarios, these assumptions prove incorrect. The flaw operates at the kernel level where SCTP state transitions are managed, making it particularly dangerous as it can be triggered through network-based attacks without requiring local system access. This type of vulnerability maps directly to CWE-476 which describes NULL pointer dereference conditions, and represents a classic case of improper handling of edge cases in protocol implementations.
The operational impact of this vulnerability extends beyond simple denial of service, though that remains the primary concern. A remote attacker capable of sending specially crafted SCTP packets to a target system can trigger a system crash resulting in complete service disruption. The kernel's response to this condition typically involves a kernel panic or system reboot, effectively rendering the affected system unavailable to legitimate users. Beyond immediate availability impacts, this vulnerability could potentially be exploited in more sophisticated attacks where multiple systems are targeted simultaneously to create cascading failures or to mask other malicious activities. The vulnerability affects all Linux kernel versions prior to 3.8.5, making it particularly widespread given the prevalence of older kernel versions in production environments.
Mitigation strategies for CVE-2013-2206 primarily focus on immediate kernel updates to versions 3.8.5 or later where the vulnerability has been patched. System administrators should prioritize patching affected systems, particularly those handling SCTP traffic or exposed to untrusted network environments. Network-level mitigations include implementing firewall rules to filter SCTP traffic when it is not required, though this approach may not be feasible in environments where SCTP is a legitimate protocol. The patch addresses the core issue by ensuring proper validation of association states before processing duplicate COOKIE ECHO chunks, preventing the NULL pointer dereference condition. Organizations should also consider monitoring for unusual SCTP traffic patterns that might indicate exploitation attempts. This vulnerability demonstrates the importance of robust input validation in kernel protocols and aligns with ATT&CK technique T1499.004 which covers network denial of service attacks. Security teams should implement comprehensive monitoring solutions to detect and respond to similar state machine vulnerabilities in network protocols, as these represent common attack vectors in kernel-based systems.