CVE-2017-6353 in Linux
Summary
by MITRE
net/sctp/socket.c in the Linux kernel through 4.10.1 does not properly restrict association peel-off operations during certain wait states, which allows local users to cause a denial of service (invalid unlock and double free) via a multithreaded application. NOTE: this vulnerability exists because of an incorrect fix for CVE-2017-5986.
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Analysis
by VulDB Data Team • 09/03/2020
The vulnerability identified as CVE-2017-6353 resides within the Linux kernel's Stream Control Transmission Protocol implementation, specifically in the net/sctp/socket.c file. This flaw represents a critical issue in the kernel's handling of SCTP association operations, where the system fails to properly enforce restrictions during specific wait states that occur during association peel-off procedures. The vulnerability affects Linux kernel versions through 4.10.1 and stems from an incorrect remediation approach for a previously identified vulnerability CVE-2017-5986, creating a regression that introduces new attack vectors. The core problem manifests when multithreaded applications attempt to perform association peel-off operations under certain temporal conditions, leading to a cascade of memory management failures that ultimately result in system instability.
The technical nature of this vulnerability involves improper locking mechanisms and state validation during SCTP association management. When threads attempt to peel off associations while the system is in transitional wait states, the kernel's synchronization primitives fail to prevent concurrent access to shared resources. This condition creates a race scenario where invalid unlock operations can occur followed by double free errors, both of which represent serious memory corruption vulnerabilities. The flaw specifically exploits the kernel's failure to properly validate the association state before permitting peel-off operations, allowing malicious or malformed applications to trigger these memory management failures through carefully constructed multithreaded workloads. The vulnerability operates at the kernel level, meaning that successful exploitation can lead to complete system compromise or denial of service conditions that may require system reboot to resolve.
The operational impact of CVE-2017-6353 extends beyond simple denial of service, as the double free and invalid unlock conditions can potentially be leveraged for more sophisticated attacks. Local attackers with access to the system can craft multithreaded applications that systematically trigger the vulnerable code path, causing kernel memory corruption that may lead to system crashes, data loss, or in extreme cases, privilege escalation opportunities. The vulnerability's presence in the kernel's core networking stack makes it particularly dangerous as it can affect any application utilizing SCTP protocols, including network services, communication applications, and system components that depend on reliable network connectivity. The fact that this vulnerability emerged from an incorrect fix for CVE-2017-5986 demonstrates the complexity of kernel security patches and the potential for remediation efforts to introduce new weaknesses.
Mitigation strategies for CVE-2017-6353 focus primarily on kernel version updates and system hardening measures. The most effective solution involves upgrading to a patched kernel version that properly addresses the association peel-off state validation issues. System administrators should also implement monitoring for unusual multithreaded SCTP activity that might indicate exploitation attempts. The vulnerability aligns with CWE-129, which covers improper validation of array indices, and CWE-415, which addresses double free conditions in memory management. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and denial of service through kernel exploitation, specifically T1068 for locally executed code and T1499 for endpoint disruption. Organizations should also consider implementing application-level restrictions on SCTP usage where possible and establish robust kernel patch management processes to prevent similar regressions from occurring in future security updates.