CVE-2014-5077 in Linux
Summary
by MITRE
The sctp_assoc_update function in net/sctp/associola.c in the Linux kernel through 3.15.8, when SCTP authentication is enabled, allows remote attackers to cause a denial of service (NULL pointer dereference and OOPS) by starting to establish an association between two endpoints immediately after an exchange of INIT and INIT ACK chunks to establish an earlier association between these endpoints in the opposite direction.
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Analysis
by VulDB Data Team • 02/10/2022
The vulnerability identified as CVE-2014-5077 represents a critical denial of service flaw within the Linux kernel's Stream Control Transmission Protocol implementation. This issue specifically affects versions through 3.15.8 and occurs within the sctp_assoc_update function located in net/sctp/associola.c. The vulnerability manifests when SCTP authentication is enabled, creating a scenario where remote attackers can exploit the protocol's association management mechanism to trigger system instability.
The technical exploitation of this vulnerability relies on a specific timing attack pattern that involves manipulating the SCTP association establishment process. Attackers can initiate a new association attempt immediately following the completion of an earlier association exchange in the reverse direction. This creates a race condition within the kernel's SCTP implementation where the sctp_assoc_update function fails to properly handle the state transitions between concurrent association attempts, leading to a NULL pointer dereference condition that ultimately results in an OOPS (kernel panic) error.
This vulnerability directly maps to CWE-476 which describes NULL pointer dereference conditions in software implementations. The flaw demonstrates how improper state management in network protocol handlers can lead to system crashes and denial of service conditions. The operational impact extends beyond simple service interruption as this vulnerability can be exploited remotely without authentication, making it particularly dangerous in networked environments where SCTP is utilized for critical communications.
The attack scenario involves a sophisticated understanding of SCTP protocol behavior and timing characteristics. When two endpoints attempt to establish associations simultaneously in opposite directions, the kernel's association update mechanism fails to properly coordinate these concurrent operations, resulting in memory corruption. This represents a classic example of how concurrent access to shared kernel data structures without proper synchronization can lead to critical system failures. The vulnerability exposes a fundamental flaw in the kernel's handling of association state transitions under authentication scenarios, where the expected sequence of INIT and INIT ACK chunks does not account for the possibility of rapid, overlapping association attempts.
Mitigation strategies for this vulnerability require immediate kernel updates to versions that contain the patched implementation of the sctp_assoc_update function. System administrators should prioritize patching affected systems, particularly those running kernel versions 3.15.8 or earlier, as the vulnerability can be exploited remotely without requiring any authentication credentials. Additionally, network administrators should consider implementing network-level controls to limit the rate of SCTP association attempts, though this approach provides only partial protection as the vulnerability exists within the kernel's core protocol handling logic. Organizations utilizing SCTP for critical applications should also implement monitoring solutions to detect unusual association patterns that might indicate exploitation attempts, while maintaining regular kernel update schedules to address similar vulnerabilities in the future.