CVE-2018-16559 in SIMATIC S7-1500 CPU
Summary
by MITRE
A vulnerability has been identified in SIMATIC S7-1500 CPU (All versions >= V2.0 and < V2.5), SIMATIC S7-1500 CPU (All versions <= V1.8.5). Specially crafted network packets sent to port 80/tcp or 443/tcp could allow an unauthenticated remote attacker to cause a Denial-of-Service condition of the device. The security vulnerability could be exploited by an attacker with network access to the affected systems on port 80/tcp or 443/tcp. Successful exploitation requires no system privileges and no user interaction. An attacker could use the vulnerability to compromise availability of the device. At the time of advisory publication no public exploitation of this security vulnerability was known.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/29/2023
This vulnerability affects Siemens SIMATIC S7-1500 programmable logic controllers where the web server component fails to properly validate incoming network requests. The flaw exists in the HTTP server implementation that handles connections on standard web ports 80/tcp and 443/tcp, which are commonly used for web-based management interfaces. The affected devices include all SIMATIC S7-1500 CPUs running firmware versions greater than or equal to V2.0 but less than V2.5, as well as those running versions less than or equal to V1.8.5. This represents a critical availability risk for industrial control systems where operational continuity is paramount.
The technical implementation flaw stems from inadequate input validation within the web server component of the PLC firmware. When specially crafted network packets are received on the vulnerable ports, the system does not properly sanitize or validate the incoming HTTP requests, leading to a potential buffer overflow or resource exhaustion condition. The vulnerability manifests as a denial-of-service scenario where legitimate network traffic is disrupted, causing the device to become unresponsive or restart unexpectedly. This behavior aligns with CWE-122, which describes buffer overflow conditions that can lead to denial-of-service impacts.
The operational impact of this vulnerability extends beyond simple service disruption as it affects critical industrial automation systems. In manufacturing environments, the S7-1500 PLCs serve as foundational components for process control, and any availability compromise can lead to production halts, quality control issues, and potential safety risks. The attack vector requires only network access to the device, making it particularly dangerous as it can be exploited from remote locations without requiring physical access or authentication credentials. The vulnerability's exploitation does not require system privileges or user interaction, which means that any network-connected device with the vulnerable firmware could be targeted by malicious actors.
Organizations should immediately implement network segmentation and access controls to restrict access to the affected ports 80/tcp and 443/tcp on S7-1500 devices. The most effective mitigation strategy involves applying the official Siemens firmware updates that address this specific vulnerability. Network administrators should also implement monitoring solutions to detect anomalous traffic patterns that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to T1499 which covers network denial-of-service attacks, and T1190 which addresses exploitation of remote services. The vulnerability demonstrates the importance of securing industrial control system components against network-based attacks and highlights the need for comprehensive vulnerability management programs in operational technology environments.