CVE-2016-2200 in SIMATIC S7-1500 CPU
Summary
by MITRE
Siemens SIMATIC S7-1500 CPU devices before 1.8.3 allow remote attackers to cause a denial of service (STOP mode transition) via crafted packets on TCP port 102.
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Analysis
by VulDB Data Team • 07/07/2022
The vulnerability identified as CVE-2016-2200 affects Siemens SIMATIC S7-1500 CPU devices operating with firmware versions prior to 1.8.3, presenting a significant security risk that enables remote attackers to induce a denial of service condition through deliberate manipulation of network traffic. This flaw specifically targets the communication protocol stack used by these industrial control systems, which are widely deployed in critical infrastructure environments including manufacturing plants, oil and gas facilities, and power generation sites where operational technology (OT) systems require robust security measures to prevent unauthorized access and maintain continuous operation.
The technical implementation of this vulnerability resides in the handling of TCP port 102 traffic, which serves as the standard port for ISO-on-TCP communication in Siemens industrial automation systems. Attackers can exploit this weakness by crafting specially formatted packets that trigger an unintended state transition within the CPU device, causing it to enter STOP mode where normal operations cease and the system becomes unresponsive to further commands. This particular flaw demonstrates a lack of proper input validation and error handling within the network protocol implementation, allowing malformed data to disrupt the normal execution flow of the industrial control system's operating environment. The vulnerability aligns with CWE-129, which addresses issues related to improper validation of input boundaries, and represents a classic example of how insufficient protocol validation can lead to system instability in industrial control environments.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially compromise the integrity of industrial processes and create cascading failures within connected systems. When a S7-1500 CPU enters STOP mode due to this attack, it can halt production lines, disrupt critical control functions, and require manual intervention to restore normal operations. The remote nature of this attack means that adversaries do not require physical access to the industrial facility, making the threat vector particularly concerning for organizations that may not have adequate network segmentation or monitoring in place. This vulnerability specifically impacts the availability aspect of the CIA triad, potentially causing significant business disruption and safety concerns in environments where continuous operation is critical for maintaining process control and preventing hazardous conditions.
Organizations affected by this vulnerability should implement immediate mitigation strategies including firmware updates to version 1.8.3 or later, which contain patches addressing the protocol handling issues that enable this attack. Network segmentation should be enforced to limit access to TCP port 102 to only authorized personnel and systems, while intrusion detection systems should be configured to monitor for unusual traffic patterns on this port. The ATT&CK framework categorizes this vulnerability under the T1071.001 technique for application layer protocol usage, specifically targeting industrial control systems through protocol manipulation. Additionally, implementing network access control lists and monitoring for malformed packets can provide early detection of potential exploitation attempts, while regular vulnerability assessments should be conducted to identify similar weaknesses in other industrial control system components that may present analogous attack surfaces.