CVE-2011-4348 in Linux
Summary
by MITRE
Race condition in the sctp_rcv function in net/sctp/input.c in the Linux kernel before 2.6.29 allows remote attackers to cause a denial of service (system hang) via SCTP packets. NOTE: in some environments, this issue exists because of an incomplete fix for CVE-2011-2482.
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Analysis
by VulDB Data Team • 03/20/2021
The vulnerability described in CVE-2011-4348 represents a critical race condition within the Linux kernel's SCTP (Stream Control Transmission Protocol) implementation that can lead to system-wide denial of service conditions. This flaw exists in the sctp_rcv function located in net/sctp/input.c and affects Linux kernel versions prior to 2.6.29. The race condition manifests when multiple SCTP packets are processed concurrently, creating a scenario where the kernel's handling of incoming packets becomes unstable and can result in system hangs or complete system lockups.
The technical nature of this vulnerability stems from improper synchronization mechanisms within the SCTP input processing code. When the sctp_rcv function receives multiple SCTP packets simultaneously, the lack of adequate locking mechanisms causes competing threads or processes to access shared data structures without proper mutual exclusion. This race condition creates a situation where the kernel's internal state becomes corrupted or inconsistent, leading to unpredictable behavior and ultimately system hang conditions. The vulnerability specifically exploits the timing dependencies between packet processing operations and the absence of proper atomic operations or mutex locks around critical sections of code that handle SCTP packet reception and processing.
From an operational impact perspective, this vulnerability poses significant risks to systems that rely on SCTP for network communication, particularly in environments where high-volume packet traffic is expected. Attackers can exploit this weakness by sending specially crafted SCTP packets to trigger the race condition, causing the target system to become unresponsive and effectively denying service to legitimate users. The system hang that results from this vulnerability can be particularly problematic in mission-critical infrastructure where availability is paramount, as it may require manual intervention or system reboot to restore normal operation. This type of denial of service attack can be executed remotely without requiring authentication, making it particularly dangerous in networked environments.
The vulnerability's relationship to CVE-2011-2482 highlights the complexity of kernel security patches and the potential for incomplete fixes that can leave systems vulnerable to similar issues. This connection suggests that while developers may have addressed one aspect of SCTP vulnerability, they inadvertently left the race condition in place, creating a false sense of security. Organizations implementing the incomplete fix for CVE-2011-2482 may still be exposed to the race condition described in CVE-2011-4348, emphasizing the importance of thorough vulnerability assessment and proper patch validation. The presence of such interdependencies between related vulnerabilities demonstrates the challenge of maintaining secure kernel implementations and underscores the need for comprehensive security testing and validation of security patches.
Mitigation strategies for this vulnerability primarily involve upgrading to Linux kernel versions 2.6.29 or later where the race condition has been properly addressed through appropriate synchronization mechanisms and locking protocols. System administrators should also implement network monitoring solutions to detect unusual SCTP packet patterns that might indicate exploitation attempts, and consider implementing rate limiting or packet filtering rules to reduce the impact of potential attacks. Additionally, organizations should conduct thorough vulnerability assessments to identify systems running affected kernel versions and ensure proper patch management processes are in place to maintain system security. The vulnerability aligns with CWE-362, which describes race conditions in concurrent programming, and represents a clear example of how improper synchronization can lead to system instability and denial of service conditions in kernel space operations.