Defenders require ever-more-advanced solutions in the quickly changing realm of cybersecurity to keep an eye on, identify, and react to criminal activity that preys on the foundations of Windows communication technology.
COMmander, a tool developed in C#, has emerged as a specialized resource targeting the often-overlooked realms of Remote Procedure Call (RPC) and Component Object Model (COM) telemetry.
By leveraging the Microsoft-Windows-RPC Event Tracing for Windows (ETW) provider, COMmander offers deep visibility into low-level RPC events, facilitating the detection of both direct attacks and those layered atop the core protocols, such as COM-based threats.
Streamlining Telemetry Enrichment
COMmander’s core design revolves around enriching defensive telemetry by capturing granular details about system RPC activity and its abstractions.
The tool operates with a configuration-driven approach, allowing users to specify detection rules in a straightforward XML format.
According to the Report, these rules act as focused filters, targeting events of interest such as specific interface UUIDs, endpoints, operation numbers (OpNum), network addresses, or process names.
Once the configuration is set and the binary is initiated, COMmander vigilantly monitors for activity matching any of the defined rules, promptly alerting defenders via terminal notifications.
One of the ongoing challenges for forensic tools in this domain is resource management. Monitoring high volumes of low-level system events can drain CPU and memory capacity, potentially impacting host performance.
Notably, COMmander is engineered to be lightweight: it consumes minimal resources while continuously delivering real-time detection capabilities.
This balance between efficacy and efficiency makes it particularly well-suited for continuous background monitoring on critical infrastructure.
Robust Integration
Deployment is streamlined for both command-line aficionados and enterprise environments. The tool is available as a standalone CLI application and a Windows service.
Installation as a service is accomplished via an administrative PowerShell script, with binaries residing in the program files directory and the service running under the Local System account.
COMmander integrates with Windows Event Viewer, logging significant milestones and detections under its own log subsection within Application and Service Logs.
Key events are tracked, including service start/stop notifications, rule loading, runtime errors, and triggered detections each mapped to a dedicated Event ID for easy correlation during incident response or routine audits.
Uninstallation is similarly straightforward, using a provided script to ensure all traces of the service are removed cleanly.
Administrators should be cautious not to run the CLI and service simultaneously, as this can lead to service instability requiring a restart.
The heart of COMmander’s detection mechanism lies in its flexible ruleset configuration. Rules are defined via an XML file (default: config.xml) placed alongside the executable.
Although only one instance of a given rule type is currently supported within a rule, users can assemble multiple rules tailored to the environment’s threat model.
For instance, defenders can monitor for DCOM invocations targeting sensitive services like WebClient or track attempts to coerce authentication using known attack techniques such as PetitPotam, simply by crafting the appropriate UUID, endpoint, or operation number filters.
In practice, these capabilities equip blue teams with actionable context around suspicious RPC and COM activity often the early indicators of lateral movement, privilege escalation, or credential theft attempts.
Administrators can quickly adapt the tool to evolving threats by updating the XML configuration, without the need for complex re-deployments or coding.
Overall, COMmander stands out as a practical and resource-friendly toolkit that empowers defenders to see deeper into the machinery of Windows interprocess and networked communication, providing an early-warning system for activities that often elude conventional endpoint detection and response (EDR) solutions.
For more detailed development insights and rule creation strategies, practitioners are encouraged to consult Jacob Acuna’s comprehensive blog post documenting the project’s conception and operational nuances.
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