How the Romulus ClickFix Platform Weaponized a Siemens Zero-Day to Drop a RAT Inside Your Network
Executive Summary
In October 2026, threat actors exploited CVE-2026-110936, a high-severity DLL sideloading vulnerability (CVSS v4: 8.4) in Siemens Software Center, to deliver a Remote Access Trojan (RAT) via the ClickFix delivery platform known as Romulus. Attackers placed a malicious archive.dll alongside a legitimately signed SiemensSoftwareCenter.exe, distributed via AllMyBasic.msi, and leveraged msiexec.exe as the execution chain. Social engineering was amplified through malicious ChatGPT Custom GPTs directing victims to fake URLs serving PowerShell-based ClickFix lures. Command-and-control infrastructure included 96.62.218[.]59 and wizardexpensive[.]com, enabling persistent remote access to compromised endpoints across industrial and enterprise environments.
This campaign illustrates a rapidly maturing attacker playbook: combining trusted software binaries, AI-augmented social engineering, and established malware-as-a-service platforms to bypass traditional defenses. The convergence of ClickFix lure delivery with OT-adjacent software like Siemens tooling signals escalating risk for critical infrastructure operators and enterprise IT teams dependent on industrial software ecosystems.
Why This Matters Now
ClickFix campaigns are accelerating in sophistication, now integrating AI-generated lures through custom ChatGPT interfaces to trick users into self-executing malicious code. The exploitation of a signed, trusted Siemens binary lowers attacker barriers significantly, and the Romulus delivery platform indicates RAT distribution is commoditized. Organizations with OT/IT convergence or Siemens tooling deployments face immediate, unpatched exposure risk if network egress and lateral movement are not actively controlled.
Attack Path Analysis
Attackers leveraged the Romulus ClickFix delivery platform and malicious ChatGPT Custom GPTs to lure victims into executing PowerShell code that dropped an MSI installer (AllMyBasic.msi) exploiting CVE-2026-110936, a DLL sideloading vulnerability in Siemens Software Center, to deploy a Remote Access Trojan. The RAT established C2 communications to attacker-controlled infrastructure, enabling persistent access, potential lateral movement within the victim environment, and downstream exfiltration of sensitive data.
Kill Chain Progression
This analysis maps confirmed threat intelligence to the full cloud kill chain to show where defensive gaps would emerge as an attack progresses.
Initial Compromise
Description
Victims were directed via malicious ChatGPT Custom GPTs to fake URLs serving ClickFix lures. Upon interaction, victims were socially engineered into copying and executing PowerShell code. This PowerShell code downloaded and executed AllMyBasic.msi via msiexec.exe, which in turn launched a trusted, signed SiemensSoftwareCenter.exe (version 3.5.8.7) alongside a malicious archive.dll, exploiting CVE-2026-110936 (DLL sideloading) to execute arbitrary code in the context of the trusted application.
Related CVEs
CVE-2026-110936
CVSS 6.7A DLL sideloading vulnerability in Siemens Software Center allows an authenticated local attacker to place a specially crafted DLL in an uncontrolled search path directory, resulting in arbitrary code execution with the privileges of the affected application. This vulnerability has been actively exploited in ClickFix campaigns to deliver remote access trojans.
Affected Products:
Siemens Siemens Software Center – < 4.0.9.8, 3.5.8.7
Exploit Status:
exploited in the wild
MITRE ATT&CK® Techniques
Phishing: Spearphishing Link
User Execution: Malicious File
Command and Scripting Interpreter: PowerShell
Hijack Execution Flow: DLL Side-Loading
System Binary Proxy Execution: Msiexec
Subvert Trust Controls: Code Signing
Remote Access Software
Ingress Tool Transfer
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
NIST SP 800-53 Rev. 5 – Malicious Code Protection, Software Integrity, and Least Functionality
Control ID: SI-3, SI-7, CM-7
PCI DSS 4.0 – Vulnerability Management, Anti-Malware Controls, and Incident Response Testing
Control ID: Requirement 6.3.3, Requirement 5.2.1, Requirement 12.10.2
NYDFS 23 NYCRR 500 – Access Privileges, Training and Monitoring, and Incident Response Plan
Control ID: 500.7, 500.14, 500.16
DORA (Digital Operational Resilience Act) – ICT Security Controls, Detection Capabilities, and ICT-Related Incident Management
Control ID: Article 9, Article 10, Article 17
NIS2 Directive – Vulnerability Handling, Supply Chain Security, and Incident Reporting
Control ID: Article 21(2)(b), Article 21(2)(e), Article 23
CISA Zero Trust Maturity Model 2.0 – Application-Level Trust Validation and Endpoint Behavioral Integrity
Control ID: Application Pillar — Application Access, Device Pillar — Endpoint Security
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Industrial Automation
Siemens Software Center exploitation via DLL sideloading and ClickFix RAT delivery directly threatens industrial automation environments relying on trusted Siemens tooling, risking lateral movement and uncontrolled C2 access across OT networks.
Computer Software/Engineering
ClickFix campaigns abusing malicious ChatGPT Custom GPTs and PowerShell MSI droppers expose software engineering teams to RAT deployment, threatening source code integrity, privileged credential theft, and exfiltration of sensitive development assets.
Information Technology/IT
IT administrators managing Siemens Software Center deployments face high-severity CVE-2026-110936 exploitation risk, with DLL sideloading enabling privilege escalation and east-west lateral movement across hybrid cloud and on-premises infrastructure.
Manufacturing
Manufacturing environments running unpatched Siemens Software Center versions below 4.0.9.8 are prime RAT delivery targets, where compromised endpoints can disrupt production systems and exfiltrate proprietary operational data via covert C2 channels.
Sources
- ClickFix Attackers Exploit Siemens Software Center Flaw to Deploy Remote Access Trojanhttps://thehackernews.com/2026/10/clickfix-attackers-exploit-siemens.htmlVerified
- Siemens PSIRT Advisory SSA-580366: DLL Sideloading Vulnerability in Siemens Software Centerhttps://productcert.siemens.com/productcert/html/ssa-580366.htmlVerified
- Siemens PSIRT Alert: Active Exploitation of CVE-2026-110936 in Siemens Software Centerhttps://productcert.siemens.com/news/2026/10/19/active-exploitation-of-cve-2026-110936-in-siemens-software-center/Verified
- Romulus ClickFix Platform Tricks Users into Deploying Legion Loader and Malware via DLL Sideloadinghttps://thehackernews.com/2026/10/romulus-clickfix-platform-tricks-users.htmlVerified
- Attackers Abuse ChatGPT Custom GPTs to Deliver ClickFix Lures and Malwarehttps://thehackernews.com/2026/09/attackers-abuse-chatgpt-custom-gpts-to.htmlVerified
- Huntress Labs Research: DLL Sideloading via Siemens Software Centerhttps://www.huntress.com/blog
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Based on the attack progression modeled above, these are the defensive controls that would constrain each stage.
Aviatrix Zero Trust CNSF is directly relevant to this incident because the attack chain depended on unrestricted outbound connectivity and unconstrained internal reachability to propagate from an endpoint compromise into broader enterprise access. By enforcing segmentation, controlled egress, and workload-level isolation, the fabric would likely have reduced the attacker's ability to establish C2, move laterally, and exfiltrate data at scale.
Control: Cloud Native Security Fabric (CNSF)
Mitigation: The CNSF fabric's visibility layer would likely surface anomalous outbound connections initiated by msiexec.exe and PowerShell toward attacker-controlled payload-hosting infrastructure, potentially constraining the successful retrieval of AllMyBasic.msi and reducing the attacker's ability to complete the delivery chain.
Control: Zero Trust Segmentation
Mitigation: Zero Trust Segmentation enforcing least-privilege workload access policies would likely constrain the blast radius of the compromised process, reducing how far an elevated-privilege RAT could reach across internal network segments even after gaining elevated rights on the local host.
Control: East-West Traffic Security
Mitigation: East-West Traffic Security enforcing microsegmentation policies across internal workloads would likely reduce the attacker's ability to reach adjacent systems, constraining unauthorized internal traffic flows originating from the compromised endpoint and limiting how many internal targets remain reachable from the initial foothold.
Control: Multicloud Visibility & Control
Mitigation: Multicloud Visibility & Control surfacing outbound connections to known-malicious IP addresses and domains would likely reduce the RAT's ability to maintain a reliable C2 channel, constraining operator command delivery and limiting the attacker's persistent remote access into the environment.
Control: Egress Security & Policy Enforcement
Mitigation: Egress Security & Policy Enforcement applying FQDN and IP-based filtering on outbound traffic would likely constrain the attacker's ability to transfer data to unauthorized external destinations, reducing the volume and reliability of exfiltration attempts over the RAT session.
If prior CNSF controls constrained C2 reliability, lateral reachability, and egress paths, the attacker's ability to stage follow-on payloads or execute destructive actions would likely be reduced to a narrower footprint, limiting ransomware propagation or credential harvesting to the initially compromised workload rather than the broader environment.
Impact at a Glance
Affected Business Functions
- Industrial Control System (ICS) and OT Network Integrity
- Software Asset Management and Enterprise Endpoint Security
- IT/OT Convergence and Remote Access Infrastructure
- Security Operations and Incident Response
Estimated downtime: 7 days
Estimated loss: N/A
Organizations running Siemens Software Center on enterprise endpoints are at risk of full remote access trojan (RAT) deployment, enabling adversaries to exfiltrate credentials, intellectual property, OT/ICS configuration data, internal network topology, and sensitive engineering or operational documentation. The ClickFix delivery chain via malicious ChatGPT Custom GPTs and MSI installers broadens the attack surface to any employee interacting with AI-based tooling. Financial loss is not publicly confirmed but potential exposure of OT/ICS environments and proprietary industrial data represents a high-value target scenario. Lateral movement from compromised endpoints into OT networks could cause significant downstream operational and safety risk.
Recommended Actions
Key Takeaways & Next Steps
- • Enforce Egress Security & Policy Enforcement with FQDN/IP blocklists to prevent RAT callback traffic to known C2 destinations (96.62.218[.]59, wizardexpensive[.]com) and restrict outbound connections to only approved, business-justified destinations.
- • Deploy Inline IPS (Suricata) with up-to-date signatures covering DLL sideloading delivery patterns, MSI-based malware droppers, and known RAT C2 traffic to detect and block exploit-stage and post-compromise network activity at initial delivery and exfiltration.
- • Apply Zero Trust Segmentation and East-West Traffic Security microsegmentation policies to isolate endpoints running sensitive ICS/OT software like Siemens Software Center, preventing lateral movement from a compromised host to other workloads or internal services.
- • Leverage Multicloud Visibility & Control and Threat Detection & Anomaly Response capabilities to baseline normal outbound connection behavior, alert on anomalous connections to new or uncategorized external destinations, and detect msiexec.exe spawning signed third-party binaries from user AppData paths.
- • Utilize Cloud Native Security Fabric (CNSF) distributed inline enforcement and real-time inspection to apply consistent policy across all egress paths, ensuring that social-engineering-induced PowerShell execution and subsequent MSI-based payload delivery are intercepted before the DLL sideloading chain completes.
