ATT&CK coverage › Technique
System Binary Proxy Execution: Regsvcs/Regasm T1218.009
Adversaries may abuse Regsvcs and Regasm to proxy execution of code through a trusted Windows utility. Regsvcs and Regasm are Windows command-line utilities that are used to register .NET Component Object Model (COM) assemblies. Both are binaries that may be digitally signed by Microsoft.
Events covered
2 catalog events are tagged with this technique by at least one rule.
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 1 | Process creation |
| Sysmon | 3 | Network connection |
Authoring guide
Patterns shared across the 6 rules above: which fields they filter on, what specific values they look for, and what they exclude. Field names are normalized across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.
Fields filtered most (7 distinct)
The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.
Top indicator values (33 distinct)
Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique.
Common exclusions (23 distinct)
Field/operator/value combinations that rules under this technique routinely exclude (top-level not() clauses). These are the false-positive paths the community has learned to filter out. A new rule that ignores the high-count entries here will likely fire on the same noisy paths.
Rules under this technique
Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.
Sigma 4 rules
- Potentially Suspicious Execution Of Regasm/Regsvcs From Uncommon Location
- Potentially Suspicious Execution Of Regasm/Regsvcs With Uncommon Extension
- RegAsm.EXE Execution Without CommandLine Flags or Files
- RegAsm.EXE Initiating Network Connection To Public IP