CVE-2012-3549 in FreeBSD
Summary
by MITRE
The SCTP implementation in FreeBSD 8.2 allows remote attackers to cause a denial of service (NULL pointer dereference and kernel panic) via a crafted ASCONF chunk.
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Analysis
by VulDB Data Team • 07/08/2024
The vulnerability identified as CVE-2012-3549 represents a critical flaw in the Stream Control Transmission Protocol implementation within FreeBSD version 8.2. This issue manifests as a denial of service condition that can be triggered by remote attackers through the deliberate construction and transmission of malformed ASCONF chunks. The SCTP protocol implementation in this specific FreeBSD version fails to properly validate incoming ASCONF chunks, creating a pathway for malicious actors to exploit the system's handling of these control messages. The flaw specifically targets the kernel-level processing of these chunks, where insufficient input validation leads to the execution of code paths that result in NULL pointer dereferences and subsequent kernel panics.
The technical nature of this vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions, and demonstrates how improper validation of input data can lead to system instability. When a crafted ASCONF chunk is received by the FreeBSD system, the SCTP implementation processes it without adequate safeguards against malformed data structures. The kernel's handling of these chunks fails to account for scenarios where expected data pointers may be null, leading to the kernel attempting to dereference these null values. This type of vulnerability falls under the ATT&CK technique T1499.004 which involves network denial of service attacks that target system resources, specifically exploiting implementation flaws in network protocols to cause system crashes.
The operational impact of this vulnerability extends beyond simple service disruption, as it can result in complete system unavailability through kernel panic conditions that require manual intervention for recovery. Remote attackers can exploit this weakness without requiring authentication or elevated privileges, making it particularly dangerous in networked environments where SCTP traffic may be present. The vulnerability affects systems running FreeBSD 8.2 and potentially other versions with similar SCTP implementations, creating widespread exposure across networks that utilize this operating system for communication services. The kernel panic conditions generated by this flaw can cause systems to reboot automatically or require administrator intervention to restore normal operation.
Mitigation strategies for CVE-2012-3549 should prioritize immediate system updates to patched versions of FreeBSD that address the SCTP implementation flaws. Organizations should implement network segmentation and access controls to limit exposure to potentially malicious SCTP traffic, while also monitoring for unusual network behavior that might indicate exploitation attempts. The implementation of proper input validation controls within the SCTP stack can provide additional defense in depth measures, ensuring that malformed ASCONF chunks are rejected before they can trigger kernel-level processing errors. System administrators should also consider disabling SCTP functionality if it is not required for operational purposes, reducing the attack surface for this specific vulnerability. Additionally, regular security audits of network protocol implementations and proactive patch management programs can help prevent similar vulnerabilities from being exploited in the future.