CVE-2022-45147 is a high-severity vulnerability affecting Siemens SIMATIC PCS neo V4.0 and multiple versions of SIMATIC STEP 7 (V16, V17, and V18 prior to Update 2). The root cause is improper restriction of the .NET BinaryFormatter during deserialization of user-controllable input, leading to CWE-502: Deserialization of Untrusted Data. The BinaryFormatter is known to be insecure when deserializing data from untrusted sources because it can instantiate arbitrary types, potentially leading to type confusion and arbitrary code execution. In this case, an attacker who can supply crafted serialized data to the affected applications can exploit this flaw to execute arbitrary code within the context of the application. The vulnerability requires local access (AV:L) but no privileges (PR:N), and user interaction is required (UI:R), indicating that an attacker must trick a user into processing malicious input. The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H), meaning successful exploitation could lead to full system compromise, data theft, or disruption of industrial control processes. The vulnerability is partially exploitable (E:P) and has an official fix status of "officially recognized" (RL:O) with confirmed reports (RC:C). No known exploits are currently in the wild. This vulnerability is related to a well-documented issue with .NET BinaryFormatter deserialization, which Microsoft has long advised against using due to its inherent insecurity. Siemens products affected are critical industrial control system (ICS) components used in process automation and manufacturing environments, making this vulnerability particularly sensitive in operational technology (OT) contexts.

The impact on European organizations using Siemens SIMATIC PCS neo and STEP 7 products can be severe. These products are widely deployed in critical infrastructure sectors such as manufacturing, energy, utilities, and chemical processing. Exploitation could allow attackers to execute arbitrary code, potentially leading to disruption of industrial processes, theft of intellectual property, or sabotage of safety systems. Given the high confidentiality, integrity, and availability impacts, successful attacks could cause operational downtime, financial losses, and safety hazards. The requirement for local access and user interaction somewhat limits remote exploitation but does not eliminate risk, especially in environments where insiders or phishing attacks are possible. European organizations with integrated OT and IT environments may face increased risk of lateral movement and escalation. The lack of known exploits in the wild suggests this is a preemptive mitigation opportunity, but the critical nature of the affected systems means that even a single successful exploit could have disproportionate consequences for national infrastructure and industrial competitiveness.

Apply Siemens-provided patches or updates as soon as they become available, especially updating SIMATIC STEP 7 to V18 Update 2 or later and SIMATIC PCS neo beyond V4.0 if patches are released. Implement strict input validation and sanitization on all interfaces that accept serialized data, ensuring only trusted sources can provide such input. Disable or replace usage of .NET BinaryFormatter in custom extensions or scripts within the affected Siemens products, migrating to safer serialization methods such as System.Text.Json or DataContractSerializer with strict type constraints. Restrict access to affected systems to trusted personnel only, enforcing strong authentication and network segmentation to reduce the risk of local exploitation. Conduct user awareness training focused on phishing and social engineering to reduce the likelihood of user interaction with malicious payloads. Monitor logs and network traffic for unusual deserialization activity or unexpected process behavior indicative of exploitation attempts. Implement application whitelisting and endpoint detection and response (EDR) solutions tailored for OT environments to detect and block unauthorized code execution. Coordinate with Siemens support and OT cybersecurity specialists to perform thorough security assessments and penetration testing focused on deserialization attack vectors.