CVE-2018-4843 in SIMATIC
Summary
by MITRE
A vulnerability has been identified in SIMATIC CP 343-1 Advanced (All versions), SIMATIC CP 343-1 Standard (All versions), SIMATIC CP 443-1 Advanced (All versions), SIMATIC CP 443-1 Standard (All versions), SIMATIC S7-1500 Software Controller incl. F (All versions < V1.7.0), SIMATIC S7-1500 incl. F (All versions < V1.7.0), SIMATIC S7-300 incl. F and T (All versions), SIMATIC S7-400 H V6 (All versions), SIMATIC S7-400 PN/DP V6 Incl. F (All versions < V6.0.7), SIMATIC S7-400 PN/DP V7 Incl. F (All versions), SIMATIC S7-410 (All versions < V8.1), SIMATIC WinAC RTX 2010 incl. F (All versions), SINUMERIK 828D (All versions), SINUMERIK 840D sl (All versions), Softnet PROFINET IO for PC-based Windows systems (All versions). Responding to a PROFINET DCP request with a specially crafted PROFINET DCP packet could cause a Denial-of-Service condition of the requesting system. The security vulnerability could be exploited by an attacker located on the same Ethernet segment (OSI Layer 2) as the targeted device. Successful exploitation requires no user interaction or privileges and impacts the availability of core functionality of the affected device. A manual restart is required to recover the system. At the time of advisory publication no public exploitation of this security vulnerability is known. Siemens provides mitigations to resolve the security issue. PROFIBUS interfaces are not affected.
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Analysis
by VulDB Data Team • 02/22/2023
This vulnerability affects a wide range of Siemens industrial automation and control devices including various CP and S7 series controllers, SINUMERIK systems, and WinAC RTX components. The flaw exists within the PROFINET Device Configuration Protocol (DCP) implementation where specifically crafted DCP packets can trigger a denial-of-service condition. The vulnerability is particularly concerning because it operates at OSI Layer 2, meaning attackers can exploit it from the same Ethernet segment as the target device without requiring network-level privileges or user interaction. This aligns with CWE-121 which addresses buffer overflow conditions that can lead to denial-of-service scenarios. The affected systems include critical industrial control equipment such as SIMATIC S7-1500 controllers, S7-400 series with various configurations, and SINUMERIK numeric control systems used in manufacturing environments.
The technical implementation flaw stems from inadequate input validation within the PROFINET DCP response handling mechanism. When a device receives a maliciously crafted DCP packet, the system fails to properly process the packet structure and subsequently crashes or becomes unresponsive. This vulnerability specifically impacts devices that have not been updated to the latest firmware versions, with the most critical versions being those below V1.7.0 for S7-1500 controllers and V6.0.7 for S7-400 PN/DP systems. The exploitation requires no authentication or elevated privileges, making it particularly dangerous for operational technology environments where network segmentation may be limited or compromised. According to ATT&CK framework, this represents a network-level denial-of-service attack that targets industrial control systems through protocol manipulation.
The operational impact of this vulnerability extends beyond simple system unavailability as it affects the core functionality of industrial control systems that are critical to manufacturing processes and operational continuity. When these systems become unresponsive, production lines may halt, safety systems could be disrupted, and process control may be lost until manual intervention occurs. The requirement for manual restart after exploitation means that the recovery process introduces additional downtime and operational risk. The vulnerability affects both standard and advanced versions of affected products, indicating a fundamental flaw in the protocol implementation rather than a specific configuration issue. Organizations relying on these industrial control systems face significant risk to their operational technology infrastructure, particularly in environments where physical security controls may be insufficient to prevent local network-based attacks.
Siemens has provided specific mitigations through firmware updates and patches that address the DCP packet handling vulnerability. The recommended approach involves updating all affected devices to the latest available firmware versions that contain the necessary protocol validation fixes. Network administrators should prioritize updating devices in production environments while maintaining proper change management procedures to avoid unintended operational disruptions. Additional network segmentation strategies should be implemented to limit the attack surface, particularly in environments where devices may be located on the same broadcast domain. Organizations should also consider implementing network monitoring solutions that can detect anomalous DCP traffic patterns and alert operators to potential exploitation attempts. The vulnerability does not affect PROFIBUS interfaces, indicating that the issue is specific to PROFINET protocol implementations within the affected Siemens products. This vulnerability highlights the importance of maintaining current firmware for industrial control systems and demonstrates how seemingly minor protocol implementation flaws can have significant operational consequences in critical infrastructure environments.