CVE-2016-2846 in SIMATIC S7-1200
Summary
by MITRE
Siemens SIMATIC S7-1200 CPU devices before 4.0 allow remote attackers to bypass a "user program block" protection mechanism via unspecified vectors.
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Analysis
by VulDB Data Team • 07/10/2022
The Siemens SIMATIC S7-1200 CPU devices represent critical components in industrial automation systems, serving as the brain for numerous manufacturing and process control applications across various sectors including energy, water treatment, and pharmaceutical production. These programmable logic controllers operate within industrial environments where security is paramount due to the potential for significant operational disruption or safety hazards. The vulnerability identified as CVE-2016-2846 specifically targets the user program block protection mechanism, which serves as a fundamental security control designed to prevent unauthorized modifications to critical control programs that govern industrial processes. This protection mechanism is essential for maintaining the integrity and reliability of industrial control systems where unauthorized changes could lead to catastrophic failures or safety incidents.
The technical flaw in CVE-2016-2846 allows remote attackers to bypass the user program block protection mechanism through unspecified vectors, effectively undermining the security architecture of these industrial control devices. This vulnerability represents a critical weakness in the authentication and authorization mechanisms that should prevent unauthorized access to program modification capabilities. The unspecified nature of the attack vectors suggests that multiple pathways may exist for exploitation, potentially including network-based attacks, protocol manipulation, or authentication bypass techniques. The vulnerability's remote exploitability means that attackers do not require physical access to the devices, significantly expanding the attack surface and potential impact. This type of flaw typically falls under CWE-284, which addresses improper access control issues, and represents a significant deviation from the expected security posture of industrial control systems that should maintain strict isolation between operational and administrative functions.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential operational technology disruption, safety compromise, and business continuity risks. Industrial control systems operating on vulnerable SIMATIC S7-1200 devices could face unauthorized program modifications that alter process control logic, potentially leading to equipment damage, production losses, or unsafe operating conditions. The ability to bypass program block protection mechanisms creates opportunities for attackers to introduce malicious code, alter process parameters, or disable safety interlocks that protect personnel and equipment. This vulnerability particularly threatens environments where these controllers are used in safety-critical applications, as the bypass of protection mechanisms could result in direct harm to workers or environmental damage. Organizations using these devices may experience significant operational disruption if attackers successfully exploit this vulnerability, potentially leading to extended downtime, costly repairs, and regulatory compliance issues.
Mitigation strategies for CVE-2016-2846 should focus on immediate firmware updates to versions that address the specific protection bypass vulnerability, as well as implementing network segmentation and access controls to limit exposure. Organizations should conduct comprehensive vulnerability assessments of their industrial control systems to identify all affected devices and evaluate the attack surface. Network monitoring and intrusion detection systems should be deployed to detect anomalous network activity that may indicate exploitation attempts. The implementation of secure network practices, including the use of network segmentation, firewalls, and access control lists, can significantly reduce the risk of remote exploitation. Additionally, organizations should implement robust change management procedures and ensure that only authorized personnel have access to program modification capabilities. This vulnerability highlights the importance of maintaining current security patches and implementing defense-in-depth strategies that protect industrial control systems from both external and internal threats. The remediation process should include thorough testing of updated firmware to ensure that security improvements do not introduce operational compatibility issues in critical control applications.