CVE-2019-3994 in elog
Summary
by MITRE
ELOG 3.1.4-57bea22 and below is affected by a denial of service vulnerability due to a use after free. A remote unauthenticated attacker can crash the ELOG server by sending multiple HTTP POST requests which causes the ELOG function retrieve_url() to use a freed variable.
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Analysis
by VulDB Data Team • 03/15/2024
The vulnerability identified as CVE-2019-3994 affects ELOG versions 3.1.4-57bea22 and earlier, representing a critical denial of service flaw that stems from improper memory management practices. This issue manifests through a use after free condition within the application's HTTP processing logic, specifically within the retrieve_url() function that handles incoming requests. The flaw allows remote attackers to exploit the system by crafting and sending multiple HTTP POST requests, which triggers the exploitation of a freed memory variable, ultimately leading to server crash and complete service disruption.
The technical root cause of this vulnerability aligns with CWE-416, which catalogs use after free conditions as a serious memory safety issue. When the retrieve_url() function processes HTTP POST requests, it appears to free memory resources associated with URL handling while simultaneously allowing subsequent code execution that references those freed memory locations. This memory management error creates a scenario where an attacker can manipulate the application's state by sending carefully constructed requests, causing the server to dereference invalid memory addresses and resulting in an immediate crash. The vulnerability's remote nature means that no authentication is required for exploitation, making it particularly dangerous as any external party can initiate the attack without prior access credentials.
The operational impact of CVE-2019-3994 extends beyond simple service disruption, as it represents a fundamental flaw in the application's memory management that could potentially be leveraged for more sophisticated attacks. Organizations relying on ELOG for logging and data management face significant risks including complete system unavailability, data loss during crash recovery, and potential exposure of sensitive information if the service is critical to their operations. The vulnerability's exploitation requires minimal resources and technical expertise, making it attractive to threat actors seeking to disrupt services. Additionally, the crash condition may leave the system in an inconsistent state, potentially creating opportunities for further exploitation or data corruption.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected ELOG installations to version 3.1.4-57bea22 or later, which contains the necessary memory management fixes. Network administrators should implement rate limiting and connection throttling mechanisms to limit the impact of potential exploitation attempts, while also monitoring for unusual traffic patterns that might indicate active exploitation. The ATT&CK framework categorizes this type of vulnerability under T1499.004 for Network Denial of Service, emphasizing the need for both preventive measures and defensive detection capabilities. Organizations should also consider implementing intrusion detection systems that can identify the specific HTTP POST patterns associated with this exploit, and maintain comprehensive backup and recovery procedures to ensure rapid restoration of services following any successful attack attempts.