CVE-2018-25015 in Linux
Summary
by MITRE • 06/08/2021
An issue was discovered in the Linux kernel before 4.14.16. There is a use-after-free in net/sctp/socket.c for a held lock after a peel off, aka CID-a0ff660058b8.
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Analysis
by VulDB Data Team • 06/10/2021
This vulnerability exists in the Linux kernel version 4.14.16 and earlier, specifically within the Stream Control Transmission Protocol implementation located in net/sctp/socket.c. The issue manifests as a use-after-free condition that occurs when a held lock is accessed after a peel off operation, creating a critical security flaw that could be exploited by malicious actors. The vulnerability is classified under the Common Weakness Enumeration as CWE-416, which represents the use of freed memory, and represents a fundamental flaw in memory management within the kernel's networking subsystem. The peel off operation in SCTP refers to the process of separating a substream from a primary association, which is a standard operation in the protocol's connection management.
The technical exploitation of this vulnerability involves a race condition scenario where a lock is held during a peel off operation, but the memory associated with that lock is freed before the lock is properly released. This creates a window where an attacker could potentially manipulate the freed memory, leading to arbitrary code execution or denial of service conditions. The memory corruption occurs because the kernel does not properly synchronize the release of memory resources with the acquisition and release of locks during the peel off process, violating fundamental principles of concurrent programming. The issue is particularly dangerous because it occurs within kernel space, where successful exploitation could result in complete system compromise.
The operational impact of this vulnerability extends beyond simple denial of service to include potential privilege escalation and system stability issues. When an attacker successfully exploits this use-after-free condition, they can manipulate kernel memory structures to execute arbitrary code with kernel privileges, effectively gaining complete control over the affected system. This represents a significant threat to server environments and embedded systems that rely on SCTP for network communications, as these systems could be compromised without proper access controls. The vulnerability affects systems running Linux kernel versions prior to 4.14.16, making it relevant to a wide range of enterprise and consumer devices that may not have received timely security updates.
Mitigation strategies for this vulnerability include immediate application of the kernel security patch released by the Linux kernel development team, which addresses the memory management issue in the SCTP implementation. Organizations should prioritize updating their systems to kernel version 4.14.16 or later, as this release contains the necessary fixes to prevent the use-after-free condition. Additionally, implementing network monitoring to detect anomalous SCTP traffic patterns and employing intrusion detection systems can help identify potential exploitation attempts. The mitigation approach aligns with ATT&CK technique T1059.007 for command and script interpreter, as exploitation could involve executing malicious code through compromised kernel memory. System administrators should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation, while maintaining regular security audits to ensure all systems remain patched against known vulnerabilities.