CVE-2016-5874 in SIMATIC NET PC-Software
Summary
by MITRE
Siemens SIMATIC NET PC-Software before 13 SP2 allows remote attackers to cause a denial of service (OPC UA service outage) via crafted TCP packets.
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Analysis
by VulDB Data Team • 09/09/2022
The vulnerability identified as CVE-2016-5874 affects Siemens SIMATIC NET PC-Software versions prior to 13 SP2, representing a critical remote denial of service flaw within industrial automation systems. This vulnerability specifically targets the OPC UA (Open Platform Communications Unified Architecture) service component that serves as a crucial communication protocol in industrial control systems. The flaw arises from insufficient input validation mechanisms within the TCP packet processing logic, allowing malicious actors to craft specially designed network packets that trigger unexpected service behavior. The vulnerability falls under the CWE-129 category of Improper Input Validation, which is a fundamental weakness in software design that permits malformed inputs to disrupt normal system operations. Within the context of industrial control systems, this vulnerability represents a significant risk as it can compromise the availability of critical automation services that support manufacturing processes and industrial operations.
The technical exploitation of this vulnerability occurs through the manipulation of TCP packets sent to the affected OPC UA service endpoints. When the software receives these crafted packets, the insufficient validation leads to a service outage that effectively renders the OPC UA communication channel unavailable. This disruption can result in complete loss of communication between industrial control systems and their monitoring interfaces, potentially causing cascading failures throughout the operational technology infrastructure. The attack vector is particularly concerning as it requires no authentication or privileged access, making it accessible to any remote attacker capable of sending network traffic to the target system. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1499.004 - Endpoint Denial of Service, where adversaries target network services to disrupt operations and compromise system availability. The specific nature of the flaw suggests that the software's TCP packet parsing routine fails to properly handle malformed or unexpected packet structures, leading to service termination or resource exhaustion.
The operational impact of this vulnerability extends beyond simple service disruption, as it can severely compromise industrial automation workflows and production continuity. When the OPC UA service becomes unavailable, it prevents operators from monitoring and controlling industrial processes, potentially leading to production downtime, quality issues, and safety concerns. The vulnerability affects systems where Siemens SIMATIC NET PC-Software is deployed for industrial communication, particularly in manufacturing environments where real-time data exchange between controllers and human-machine interfaces is essential. Organizations utilizing these systems face the risk of extended operational interruptions that can result in significant financial losses and potential safety hazards. The vulnerability's classification as a denial of service issue means that even a single successful attack can cause substantial disruption to industrial operations, with recovery requiring system restarts and potential manual intervention to restore normal functionality. The impact is further amplified in environments where multiple systems depend on the affected OPC UA services for coordinated operations.
Mitigation strategies for CVE-2016-5874 primarily focus on applying the vendor-provided security patches and updates to Siemens SIMATIC NET PC-Software versions 13 SP2 and later. Organizations should implement network segmentation and access controls to limit exposure of affected systems to untrusted networks, utilizing firewalls and network access control lists to restrict TCP port access to the OPC UA service. Network monitoring solutions should be deployed to detect unusual traffic patterns and potential exploitation attempts, with intrusion detection systems configured to identify malformed TCP packets targeting the affected service. Regular vulnerability assessments and security audits of industrial control systems should be conducted to identify and remediate similar weaknesses in other components of the operational technology infrastructure. System administrators should also implement proper network hygiene practices including regular patch management procedures and maintaining up-to-date security configurations for all industrial communication components. The remediation process requires careful planning to avoid disrupting ongoing industrial operations, potentially involving staged updates and rollback procedures to ensure continuous production availability while addressing the vulnerability.