CVE-2017-15115 in Linux
Summary
by MITRE • 01/25/2023
The sctp_do_peeloff function in net/sctp/socket.c in the Linux kernel before 4.14 does not check whether the intended netns is used in a peel-off action, which allows local users to cause a denial of service (use-after-free and system crash) or possibly have unspecified other impact via crafted system calls.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2017-15115 resides within the Linux kernel's Stream Control Transmission Protocol implementation, specifically in the sctp_do_peeloff function located at net/sctp/socket.c. This flaw represents a critical security issue that affects Linux kernel versions prior to 4.14, where the kernel fails to properly validate network namespace contexts during SCTP peel-off operations. The vulnerability manifests when a local user crafts specific system calls that trigger the peel-off mechanism without ensuring proper namespace validation, creating a dangerous condition that can lead to system instability and potential privilege escalation.
The technical root cause of this vulnerability stems from insufficient input validation within the SCTP socket implementation, where the sctp_do_peeloff function does not verify that the target network namespace matches the expected context for the peel-off operation. This oversight creates a use-after-free condition when the function attempts to process a peel-off action on a socket that has already been freed or moved between network namespaces. The flaw operates at the kernel level, bypassing normal user-space protections and allowing malicious local processes to exploit the race condition inherent in the namespace handling mechanism. According to CWE-416, this vulnerability represents a classic use-after-free scenario where kernel memory is accessed after it has been released, while the ATT&CK framework categorizes this under privilege escalation techniques through kernel vulnerabilities.
The operational impact of CVE-2017-15115 extends beyond simple denial of service, as local attackers can potentially leverage this vulnerability to execute arbitrary code with kernel privileges. The system crash resulting from the use-after-free condition can be reliably triggered by a local user, making this a significant threat to system stability and availability. Additionally, the unspecified other impacts mentioned in the description suggest potential privilege escalation opportunities that could allow attackers to gain elevated system access. The vulnerability affects systems running Linux kernel versions 4.13 and earlier, where the proper namespace validation checks were not implemented, leaving systems exposed to exploitation through crafted SCTP system calls that manipulate network namespace contexts.
Mitigation strategies for this vulnerability require immediate kernel updates to version 4.14 or later, where the proper namespace validation has been implemented in the sctp_do_peeloff function. System administrators should prioritize patching affected systems, particularly those running older kernel versions, as the vulnerability can be exploited by any local user with access to the system. Network administrators should also monitor for potential exploitation attempts by watching for unusual SCTP-related system calls or kernel crashes. The fix implemented in kernel 4.14 addresses the core issue by adding proper namespace validation checks before allowing peel-off operations to proceed, ensuring that kernel memory is not accessed after it has been freed or moved between network contexts. Organizations should also consider implementing additional security monitoring to detect potential exploitation attempts through kernel-level anomalies that could indicate this vulnerability being targeted.