CVE-2019-3996 in elog
Summary
by MITRE
ELOG 3.1.4-57bea22 and below can be used as an HTTP GET request proxy when unauthenticated remote attackers send crafted HTTP POST requests.
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Analysis
by VulDB Data Team • 03/15/2024
The vulnerability identified as CVE-2019-3996 affects ELOG versions 3.1.4-57bea22 and earlier, representing a significant security flaw that enables unauthorized remote attackers to leverage the application as an intermediary HTTP proxy. This vulnerability stems from the application's improper handling of HTTP requests, specifically when processing POST requests that contain crafted payloads designed to exploit the proxy functionality. The flaw allows attackers to bypass authentication mechanisms and utilize the vulnerable system as a conduit for forwarding HTTP GET requests to arbitrary destinations, effectively transforming the legitimate application into a malicious proxy server.
The technical implementation of this vulnerability resides in the application's HTTP request processing logic where it fails to properly validate or sanitize incoming POST requests that contain HTTP method switching or proxy forwarding directives. When an unauthenticated attacker sends a specially crafted POST request, the vulnerable ELOG application interprets these requests as legitimate proxy instructions rather than malicious payloads. This misconfiguration creates a path where the application acts as a man-in-the-middle, forwarding requests to external servers without proper authorization or logging. The vulnerability is classified under CWE-829 as it allows for the inclusion of functionality that enables unauthorized access to external resources through the application's proxy capabilities.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with a potential pathway for reconnaissance, data exfiltration, and further exploitation within network environments. An attacker can use this proxy functionality to probe internal network resources that would normally be inaccessible from the internet, effectively expanding their attack surface. The vulnerability also poses risks to the integrity of the application's logs and audit trails, as malicious requests can be routed through the system without proper attribution. Additionally, this proxy capability could be leveraged for conducting distributed denial-of-service attacks or as part of broader exploitation chains targeting other systems within the same network infrastructure.
Organizations utilizing vulnerable ELOG versions should implement immediate mitigations including restricting network access to the application, implementing proper authentication controls, and disabling unnecessary proxy functionality. The recommended approach involves applying the vendor-provided patch or upgrading to a non-vulnerable version of the application. Network segmentation and firewall rules should be configured to limit access to the vulnerable system from untrusted networks. From an ATT&CK perspective, this vulnerability maps to techniques involving proxy usage and command and control communications, where the compromised system becomes a tool for attackers to maintain persistence and conduct operations while evading detection. Security monitoring should be enhanced to detect anomalous proxy behavior patterns and unusual HTTP request routing that may indicate exploitation attempts.