CVE-2013-0700 in SIMATIC S7-1200 PLC
Summary
by MITRE
Siemens SIMATIC S7-1200 PLCs 2.x and 3.x allow remote attackers to cause a denial of service (defect-mode transition and control outage) via crafted packets to TCP port 102 (aka the ISO-TSAP port).
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Analysis
by VulDB Data Team • 01/02/2022
The Siemens SIMATIC S7-1200 programmable logic controllers represent critical components in industrial automation systems, serving as the backbone for controlling manufacturing processes and industrial equipment across various sectors including automotive, chemical, and power generation. These devices operate within the industrial control systems (ICS) domain and are specifically designed for use in harsh industrial environments where reliability and continuous operation are paramount. The vulnerability described in CVE-2013-0700 affects firmware versions 2.x and 3.x of these controllers, creating a significant security risk that could compromise the operational integrity of industrial processes. The affected communication protocol operates over TCP port 102, which is the standard port for ISO Transport Service Access Point (ISO-TSAP) communication used in industrial automation protocols. This port serves as the primary interface for communication between programmable logic controllers and various industrial devices, making it a critical pathway for maintaining system control and monitoring functions.
The technical flaw exploited in this vulnerability stems from insufficient input validation and error handling within the S7-1200 PLC's communication stack. When remote attackers send specially crafted packets to the designated TCP port 102, the device fails to properly process these malformed communications, leading to unexpected behavior in the controller's operational state. The vulnerability specifically triggers a defect-mode transition within the PLC, which represents a protective mechanism that activates when the system detects abnormal conditions or errors. This defect mode transition essentially causes the controller to enter a non-operational state where it ceases normal control functions and may even shut down connected processes. The underlying issue lies in the protocol implementation's lack of proper bounds checking and validation of incoming data packets, creating a path for attackers to manipulate the controller's operational state through network-based attacks without requiring physical access or authentication credentials.
The operational impact of this vulnerability extends far beyond simple service interruption, as it can lead to complete control outages in industrial processes that depend on these controllers. When a Siemens S7-1200 PLC enters defect mode due to the crafted packet attack, the affected industrial processes may experience immediate shutdowns, production halts, and potential safety hazards. The controller's inability to maintain normal operational functions can result in cascading failures throughout connected industrial systems, potentially affecting multiple processes simultaneously. In critical infrastructure environments such as power plants, chemical processing facilities, or manufacturing lines, this type of denial of service attack could result in significant financial losses, safety risks, and regulatory compliance issues. The vulnerability particularly affects environments where continuous operation is required, as the controller's transition to defect mode could trigger emergency shutdown procedures that are designed to protect equipment but may also disrupt normal operations.
The exploitation of this vulnerability aligns with attack patterns identified in the MITRE ATT&CK framework under the 'Execution' and 'Persistence' domains, where adversaries may leverage communication protocol flaws to gain control over industrial systems. From a CWE perspective, this vulnerability maps to CWE-129, which describes improper validation of input boundaries, and CWE-248, which addresses exposure of an exception to the calling environment. Organizations utilizing Siemens S7-1200 PLCs should implement comprehensive network segmentation strategies to isolate these critical devices from general network access, while also deploying network monitoring solutions to detect anomalous traffic patterns on TCP port 102. The recommended mitigations include applying firmware updates from Siemens that address the communication protocol validation issues, implementing network access controls to restrict access to port 102, and establishing intrusion detection systems specifically designed for industrial protocols. Additionally, organizations should consider implementing redundant control systems and emergency shutdown procedures that can maintain operational safety even when primary controllers are compromised, ensuring that industrial processes can continue with minimal disruption during security incidents.