CVE-2020-8448 in OSSEC-HIDS
Summary
by MITRE
In OSSEC-HIDS 2.7 through 3.5.0, the server component responsible for log analysis (ossec-analysisd) is vulnerable to a denial of service (NULL pointer dereference) via crafted messages written directly to the analysisd UNIX domain socket by a local user.
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Analysis
by VulDB Data Team • 03/27/2024
The vulnerability identified as CVE-2020-8448 affects the OSSEC-HIDS log analysis server component known as ossec-analysisd, which is part of the Open Source Security Event Correlation and Analysis system. This security flaw exists in versions ranging from 2.7 through 3.5.0, making it a long-standing issue that could potentially impact organizations relying on this intrusion detection system for security monitoring and log analysis operations.
The technical flaw manifests as a NULL pointer dereference condition within the ossec-analysisd process when handling crafted messages transmitted directly to the analysisd UNIX domain socket. This vulnerability specifically targets the server component responsible for processing and analyzing security events from various sources, including system logs, application logs, and network traffic. The NULL pointer dereference occurs when the application attempts to access memory at address zero, typically when a pointer expected to contain a valid memory reference instead contains a NULL value. This condition is classified as a CWE-476, which represents a NULL Pointer Dereference vulnerability in the Common Weakness Enumeration catalog.
The operational impact of this vulnerability is significant as it enables a local user to trigger a denial of service condition against the ossec-analysisd service. Since the attack vector involves writing crafted messages directly to the UNIX domain socket, any user with access to the system can potentially exploit this weakness, making it particularly dangerous in multi-user environments or when the service runs with elevated privileges. The denial of service condition results in the termination of the ossec-analysisd process, which disrupts the log analysis functionality and potentially leaves the system vulnerable to security events that would normally be detected and correlated by the OSSEC-HIDS system. This interruption of security monitoring capabilities creates a window of opportunity for malicious actors to exploit other vulnerabilities or conduct attacks without detection.
From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1499.004, which involves network disruption through denial of service attacks. The local privilege escalation aspect of this vulnerability means that attackers who already have system access can leverage this flaw to compromise the availability of security monitoring services. Organizations implementing OSSEC-HIDS should consider this vulnerability within their broader security posture, particularly in environments where the service operates with root privileges or where local access is not strictly controlled. The vulnerability demonstrates a critical flaw in input validation and error handling within the log analysis component, highlighting the importance of robust memory management practices in security monitoring applications.
The recommended mitigation strategy involves upgrading to OSSEC-HIDS version 3.5.1 or later, where this vulnerability has been addressed through proper NULL pointer validation and error handling mechanisms. Additionally, system administrators should implement strict access controls to the UNIX domain socket used by ossec-analysisd, ensuring that only authorized processes can write to it. Network segmentation and monitoring of socket access patterns can help detect potential exploitation attempts. Organizations should also consider implementing additional logging and alerting mechanisms to monitor for service disruptions that could indicate exploitation of this vulnerability. The fix implemented in the updated versions typically includes enhanced input validation and proper NULL pointer checks before memory access operations, preventing the application from crashing when encountering malformed messages in the UNIX domain socket communication channel.