CVE-2004-1016 in Linux
Summary
by MITRE
The scm_send function in the scm layer for Linux kernel 2.4.x up to 2.4.28, and 2.6.x up to 2.6.9, allows local users to cause a denial of service (system hang) via crafted auxiliary messages that are passed to the sendmsg function, which causes a deadlock condition.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability described in CVE-2004-1016 represents a critical flaw in the Linux kernel's scm (socket control message) layer that affects kernel versions 2.4.x through 2.4.28 and 2.6.x through 2.6.9. This issue stems from improper handling of auxiliary messages within the scm_send function, which forms part of the socket communication framework that enables passing additional metadata between processes. The vulnerability specifically targets the kernel's ability to process control messages that are transmitted alongside socket data, creating a scenario where malformed or specially crafted auxiliary data can trigger unexpected behavior in the kernel's message handling mechanisms.
The technical implementation of this vulnerability involves a deadlock condition that occurs when the scm_send function processes crafted auxiliary messages passed through the sendmsg system call. When these malformed messages are received, the kernel's internal locking mechanisms become compromised, leading to a state where multiple kernel threads become blocked waiting for resources that will never be released. This particular flaw falls under CWE-362, which describes Race Conditions, as the vulnerability exploits a timing issue in kernel thread synchronization where the deadlock occurs due to improper resource management during message processing. The vulnerability can be classified as a local privilege escalation vector since it requires local system access but can result in a complete system hang, making it particularly dangerous in multi-user environments where local users could potentially disrupt system operations.
The operational impact of CVE-2004-1016 extends beyond simple denial of service, as it can cause complete system instability and require manual intervention to restore normal operations. When exploited, the vulnerability results in system hang conditions that may persist until a system reboot is performed, effectively rendering the affected machine unusable until manual intervention occurs. This type of vulnerability is particularly concerning in server environments where uptime is critical, as it can be used to perform persistent denial of service attacks against legitimate users. The vulnerability's exploitation aligns with ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" through resource exhaustion or system hang conditions. Organizations running affected kernel versions face significant operational risk, as this vulnerability can be leveraged to disrupt services without requiring elevated privileges, making it an attractive target for malicious actors seeking to cause disruption.
Mitigation strategies for CVE-2004-1016 primarily involve upgrading to kernel versions that contain the appropriate patches, specifically those released after the vulnerability was identified in 2004. The fix implemented by kernel developers involved modifying the scm_send function to properly validate auxiliary message parameters and implement correct locking mechanisms to prevent the deadlock condition from occurring. System administrators should prioritize patching affected systems, particularly in environments where local users have access to potentially malicious code execution. Additionally, monitoring for unusual socket communication patterns and implementing proper access controls can help detect potential exploitation attempts, though these measures do not prevent the vulnerability itself. Organizations should also consider implementing kernel hardening techniques such as disabling unnecessary socket features and employing intrusion detection systems to monitor for suspicious network activity that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of kernel security and the need for regular security updates in maintaining system integrity and preventing exploitation of known vulnerabilities.