CVE-2016-8562 in SIMATIC CP 1543-1
Summary
by MITRE
Siemens SIMATIC CP 1543-1 before 2.0.28, when SNMPv3 write access or SNMPv1 is enabled, allows remote authenticated users to cause a denial of service by modifying SNMP variables.
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Analysis
by VulDB Data Team • 02/04/2025
The vulnerability identified as CVE-2016-8562 affects Siemens SIMATIC CP 1543-1 industrial communication processors, which are widely deployed in industrial control systems and supervisory control and data acquisition environments. This device serves as a critical communication interface between industrial networks and enterprise systems, making its security paramount for operational technology infrastructure. The flaw resides in the Simple Network Management Protocol implementation within these devices, specifically when SNMPv3 write access or SNMPv1 is enabled, creating a pathway for malicious actors to disrupt system operations.
The technical exploitation of this vulnerability occurs through manipulation of SNMP variables that control the device's operational parameters. When remote authenticated users with appropriate credentials access the system, they can modify specific SNMP variables that govern the device's behavior, leading to a denial of service condition. This represents a privilege escalation vulnerability where legitimate users can leverage their access rights to cause system disruption. The flaw stems from inadequate input validation and insufficient access controls within the SNMP management interface, allowing modification of critical operational parameters that should remain protected from unauthorized changes.
From an operational perspective, this vulnerability poses significant risks to industrial environments where continuous operation is critical for process control and safety systems. The denial of service condition can result in complete loss of communication capabilities between the industrial network and enterprise systems, potentially leading to production halts, safety system failures, or emergency shutdowns. The impact extends beyond simple service disruption as industrial control systems often operate in environments where network availability is mission-critical. This vulnerability specifically aligns with CWE-284, which addresses improper access control, and demonstrates how weak access controls in network management protocols can lead to system availability compromises.
The attack vector requires remote authenticated access, meaning that an attacker must already possess valid credentials to exploit the vulnerability, but this still represents a significant risk in environments where credential compromise can occur through various means including social engineering, password reuse, or network sniffing attacks. The vulnerability affects devices running firmware versions prior to 2.0.28, making it essential for organizations to maintain current firmware updates as part of their cybersecurity hygiene. Organizations implementing the affected devices should consider network segmentation and access control measures to limit exposure, while also implementing robust credential management practices and monitoring for unauthorized SNMP access attempts. The remediation strategy involves applying the vendor-provided firmware update to version 2.0.28 or later, which addresses the improper access control issue by implementing proper input validation and access restriction mechanisms for SNMP variables.
This vulnerability demonstrates the broader challenge of securing industrial control systems where operational technology and information technology converge, highlighting the need for comprehensive security strategies that address both traditional cybersecurity threats and industrial-specific operational risks. The attack pattern aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation, as attackers can leverage legitimate access to cause service disruption. Organizations should implement continuous monitoring of SNMP traffic and establish baseline operational states for their industrial devices to detect anomalous behavior that might indicate exploitation attempts. The vulnerability underscores the importance of maintaining current security patches and implementing defense-in-depth strategies that protect against both external and internal threats in industrial environments where system availability directly impacts operational safety and business continuity.