CVE-2014-1699 in SIMATIC Wincc Open Architecture
Summary
by MITRE
Siemens SIMATIC WinCC OA before 3.12 P002 January allows remote attackers to cause a denial of service (monitoring-service outage) via malformed HTTP requests to port 4999.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability identified as CVE-2014-1699 affects Siemens SIMATIC WinCC OA versions prior to 3.12 P002 January, representing a critical remote denial of service weakness that specifically targets the monitoring service component. This issue manifests when the system receives malformed HTTP requests directed at port 4999, which serves as the default communication port for the WinCC OA monitoring service. The flaw stems from insufficient input validation mechanisms within the HTTP request processing layer, allowing attackers to craft specially malformed requests that trigger unexpected behavior in the monitoring service daemon.
The technical implementation of this vulnerability involves the exploitation of a buffer overflow or memory corruption condition within the HTTP parser component of the WinCC OA monitoring service. When the service receives a malformed HTTP request containing oversized headers, malformed content, or crafted payload sequences, it fails to properly validate the incoming data before processing. This lack of proper input sanitization creates a condition where the monitoring service either crashes or becomes unresponsive, resulting in complete service outage. The vulnerability specifically targets the HTTP protocol implementation that handles requests to port 4999, which is critical for system monitoring and administrative functions within the WinCC OA environment.
The operational impact of CVE-2014-1699 extends beyond simple service disruption, as it can compromise the integrity of industrial control systems that rely on continuous monitoring for operational safety. Organizations utilizing Siemens SIMATIC WinCC OA systems face significant risk of production downtime, especially in critical infrastructure environments where monitoring services are essential for maintaining operational visibility. The remote nature of this attack means that adversaries can exploit the vulnerability from outside the network perimeter without requiring physical access or local credentials, making it particularly dangerous for industrial environments that may have limited network segmentation. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of how improper input validation can lead to system instability and service disruption.
The attack vector for this vulnerability follows standard remote exploitation patterns common in industrial control systems, where network-based attacks can be launched against exposed services. According to ATT&CK framework, this represents a denial of service technique that can be categorized under T1499, which covers network denial of service attacks. Organizations should implement network segmentation to restrict access to port 4999, deploy intrusion detection systems to monitor for malformed HTTP requests, and ensure that all WinCC OA installations are updated to version 3.12 P002 or later. Additionally, applying network access controls and monitoring for unusual traffic patterns on port 4999 can help detect potential exploitation attempts. The remediation process requires updating the WinCC OA software to the patched version that includes proper input validation and error handling mechanisms, while also conducting thorough vulnerability assessments of industrial control system environments to identify other potentially exposed services.