CVE-2015-6484 in CODESYS Gateway Server
Summary
by MITRE
3S-Smart CODESYS Gateway Server before 2.3.9.48 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted (1) GET or (2) POST request.
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Analysis
by VulDB Data Team • 11/18/2024
The CVE-2015-6484 vulnerability affects the 3S-Smart CODESYS Gateway Server version 2.3.9.48 and earlier, representing a critical denial of service flaw that can be exploited remotely by attackers. This vulnerability stems from improper input validation within the server's handling of HTTP requests, specifically when processing GET and POST methods. The flaw manifests as a NULL pointer dereference condition that occurs when the server receives malformed or crafted requests, leading to an immediate daemon crash and subsequent service unavailability.
The technical implementation of this vulnerability resides in the server's protocol handling layer where it fails to properly validate incoming HTTP request parameters before attempting to process them. When a malicious actor sends a specially crafted GET or POST request, the server's internal code attempts to dereference a NULL pointer during request parsing, causing an unhandled exception that terminates the daemon process. This behavior aligns with CWE-476 which describes NULL pointer dereference vulnerabilities, and represents a classic example of inadequate error handling in network services. The vulnerability's remote exploitability means that attackers do not require physical access or authentication credentials to trigger the denial of service condition, making it particularly dangerous in operational technology environments where availability is critical.
The operational impact of CVE-2015-6484 extends beyond simple service disruption, as it can affect industrial control systems and automation environments that rely on continuous operation of CODESYS Gateway Server components. In manufacturing and critical infrastructure settings, such a vulnerability can lead to production halts, safety system degradation, or cascading failures when the gateway server becomes unavailable. The vulnerability's exploitation can be automated and does not require sophisticated techniques, making it attractive to threat actors seeking to disrupt operations. From an attack perspective, this flaw maps to ATT&CK technique T1499.004 which covers network denial of service attacks, and the lack of authentication requirements means it can be exploited as part of broader reconnaissance or disruption campaigns.
Mitigation strategies for CVE-2015-6484 should prioritize immediate patching of affected systems to version 2.3.9.48 or later, which contains the necessary fixes for proper input validation and error handling. Network segmentation and access controls should be implemented to limit exposure of the gateway server to untrusted networks, while monitoring systems should be deployed to detect unusual traffic patterns that may indicate exploitation attempts. Additionally, implementing intrusion detection systems with signature matching for known malicious request patterns can provide early warning of attempted exploitation. Organizations should also conduct comprehensive vulnerability assessments to identify other potentially affected systems within their industrial control networks, as similar input validation flaws may exist in other components of the CODESYS ecosystem. The vulnerability serves as a reminder of the importance of robust input validation and proper error handling in industrial network services, particularly those handling HTTP protocols in critical infrastructure environments.