Trusted Developer Utilities Proxy Execution: MSBuild T1127.001

Events covered

6 catalog events are tagged with this technique by at least one rule.

Authoring guide

Patterns shared across the 22 rules above: which fields they filter on, what specific values they look for, and what they exclude. The catalog normalizes field names 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 (25 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 (144 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. Click a value to expand the rules under this technique that use it.

Exclusions (98 distinct)

Field/operator/value combinations excluded by rules under this technique (top-level not() clauses), sorted by how many rules exclude each. 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. Click a value to expand the rules under this technique that exclude it.

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 1 rule

• Silenttrinity Stager Msbuild Activity

Elastic 14 rules

• Delayed Execution via Ping
• Execution of Persistent Suspicious Program
• Execution via MS VisualStudio Pre/Post Build Events
• Microsoft Build Engine Started an Unusual Process
• Microsoft Build Engine Started by a Script Process
• Microsoft Build Engine Started by a System Process
• Microsoft Build Engine Started by an Office Application
• Microsoft Build Engine Using an Alternate Name
• MsBuild Making Network Connections
• Network Activity to a Suspicious Top Level Domain
• Potential Credential Access via Trusted Developer Utility
• Process Injection by the Microsoft Build Engine
• Suspicious Execution from a Mounted Device
• Unusual Network Activity from a Windows System Binary

Splunk 6 rules

• Microsoft Build Engine Suspicious Parent Process (Sysmon)
• Microsoft Build Engine Suspicious Parent Process (Windows Event Log)
• MSBuild Suspicious Spawned By Script Process
• Suspicious msbuild path
• Suspicious MSBuild Rename
• Suspicious MSBuild Spawn

Kusto 1 rule

• Powershell Empire Cmdlets Executed in Command Line