This threat involves nine malicious NuGet packages published by a user named "shanhai666" in 2023 and 2024, designed to deliver time-delayed payloads that activate in August 2027 and November 2028. The packages have collectively been downloaded approximately 9,488 times, indicating a significant potential reach. The most critical package, Sharp7Extend, targets industrial programmable logic controllers (PLCs), specifically Siemens S7 devices, by leveraging the legitimate Sharp7 .NET library to mask its malicious payload. It exploits C# extension methods to intercept database queries and PLC operations without modifying original code, enabling stealthy execution of malicious logic. After installation, Sharp7Extend immediately begins a sabotage phase with a 20% chance to randomly terminate processes and, after a randomized delay of 30-90 minutes, causes silent write failures to PLCs 80% of the time. This dual sabotage mechanism continues until June 6, 2028. Other packages target SQL Server, PostgreSQL, and SQLite databases with delayed triggers set for August 2027 and November 2028. The staggered activation timeline allows the attacker to maximize victim collection and delay detection. The probabilistic nature of the attacks and the long delay between installation and activation are intended to obscure the attack's origin, complicating incident response and forensic investigations. The campaign demonstrates sophisticated supply chain attack techniques rarely seen in NuGet ecosystems. The threat actor's identity is unknown but suspected to be of Chinese origin based on code analysis and naming conventions. All malicious packages have been removed from NuGet, but organizations that installed them remain at risk. This attack highlights the dangers of supply chain compromises, especially in critical infrastructure and manufacturing environments reliant on PLCs and database systems.

For European organizations, especially those in manufacturing, industrial automation, and critical infrastructure sectors, this threat poses significant operational and safety risks. The Sharp7Extend package targets Siemens S7 PLCs, widely used in European industrial environments, potentially causing random process terminations and silent write failures that could disrupt manufacturing processes, damage equipment, or compromise safety systems. Database sabotage from other packages could lead to data corruption, loss of integrity, and operational downtime affecting business continuity. The delayed activation and probabilistic execution increase the risk of undetected sabotage, complicating timely incident response and increasing potential damage. The stealthy nature of the attack could result in prolonged undetected presence, leading to cascading failures in industrial control systems and critical business applications. European organizations relying on .NET and NuGet packages for software development and industrial control integration are particularly vulnerable. The attack could also undermine trust in software supply chains, necessitating increased scrutiny and controls. The inability to trace the attack back to its origin complicates legal and regulatory responses, potentially affecting compliance with EU cybersecurity directives such as NIS2 and GDPR if data integrity or availability is impacted.

1. Conduct comprehensive software supply chain audits to identify any usage of the malicious NuGet packages, including Sharp7Extend and the other identified packages, across all projects and environments. 2. Implement strict dependency management policies, including locking package versions, using trusted package sources, and employing tools for automated scanning of dependencies for known malicious or vulnerable packages. 3. Deploy runtime monitoring specifically tailored for industrial control systems and database operations to detect anomalous behaviors such as unexpected process terminations, write failures, or unusual query patterns. 4. Employ behavioral anomaly detection solutions for PLC communications and database transactions to identify sabotage attempts early. 5. Establish incident response playbooks that include forensic capabilities to investigate delayed and probabilistic malware activations, focusing on timeline reconstruction and correlation of events. 6. Engage with software vendors and the community to ensure rapid patching and removal of compromised dependencies. 7. Educate developers and DevOps teams on the risks of supply chain attacks and the importance of verifying package integrity and provenance. 8. Consider isolating critical ICS and database systems from general IT networks to limit malware propagation. 9. Use cryptographic verification of packages and implement allowlists for approved dependencies. 10. Regularly update and patch all software components to reduce exposure to known threats.