CVE-2018-16558 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.
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Analysis
by VulDB Data Team • 08/29/2023
This vulnerability affects Siemens SIMATIC S7-1500 programmable logic controllers where specifically crafted network packets targeting ports 80/tcp or 443/tcp can trigger a denial-of-service condition without requiring authentication or user interaction. The affected devices include 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. The flaw represents a critical availability threat that undermines the operational continuity of industrial control systems in manufacturing and process automation environments. This vulnerability aligns with CWE-119 which addresses memory safety issues, and specifically relates to improper input validation in network protocol handling.
The technical implementation of this vulnerability stems from insufficient validation of incoming network traffic on the web interface ports of the S7-1500 controllers. When malformed packets are received on ports 80 or 443, the controller's web server component fails to properly handle the malformed data structures, leading to system instability and potential crash conditions. The attack vector requires only network access to the target device and can be executed remotely without any authentication credentials or privileged access. This characteristic places the vulnerability squarely within the ATT&CK framework under the T1499 technique for network denial of service attacks, specifically targeting industrial control systems.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise critical manufacturing processes and industrial automation workflows. When a S7-1500 controller becomes unavailable due to this denial-of-service condition, production lines may halt, safety systems could be disrupted, and process control operations might fail entirely. The vulnerability affects devices in sectors including automotive manufacturing, chemical processing, and power generation where continuous operation is essential. Organizations utilizing these controllers in operational technology environments face significant risk exposure, particularly in environments where network segmentation is inadequate or where direct internet access is permitted to industrial control systems.
Mitigation strategies should prioritize immediate firmware updates from Siemens to address the vulnerability in affected versions. Network segmentation and access control measures including firewall rules that restrict access to ports 80 and 443 to trusted networks only can provide temporary protection. Additionally, implementing network monitoring and intrusion detection systems to identify suspicious traffic patterns on these ports can help detect exploitation attempts. The vulnerability demonstrates the importance of securing industrial control system interfaces and highlights the need for comprehensive security assessments of operational technology environments. Organizations should also consider implementing network access control lists and disabling unnecessary services on industrial devices to reduce attack surface exposure. Regular security assessments and vulnerability management programs are essential to maintain protection against similar threats in industrial automation environments.