Masquerading: Rename Legitimate Utilities T1036.003
Tactic: Stealth
Adversaries may rename legitimate / system utilities to try to evade security mechanisms concerning the usage of those utilities. Security monitoring and control mechanisms may be in place for legitimate utilities adversaries are capable of abusing, including both built-in binaries and tools such as PSExec, AutoHotKey, and IronPython. It may be possible to bypass those security mechanisms by renaming the utility prior to utilization (ex: rename rundll32.exe). An alternative case occurs when a legitimate utility is copied or moved to a different directory and renamed to avoid detections based on these utilities executing from non-standard paths.
Events covered
12 catalog events are tagged with this technique by at least one rule.
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Sysmon | Event ID 7 | Image loaded |
| Sysmon | Event ID 11 | FileCreate |
| Sysmon | Event ID 13 | RegistryEvent (Value Set) |
| Security-Auditing | Event ID 4663 | An attempt was made to access an object. |
| Security-Auditing | Event ID 4688 | A new process has been created. |
| Defender-DeviceProcessEvents | any | Process activity (any) |
| Defender-DeviceProcessEvents | ProcessCreated | Process created |
| ESF | exec | Process Execution (Notify) |
| PowerShell | Event ID 4103 | Payload Context: ContextInfo User Data: UserData. |
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
| PowerShell | Event ID 400 | Event ID 400 |
Authoring guide
Patterns shared across the 55 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 (32 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 (635 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 (160 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 27 rules
- File Download Via Bitsadmin
- File Download Via Bitsadmin To A Suspicious Target Folder
- File With Suspicious Extension Downloaded Via Bitsadmin
- LOL-Binary Copied From System Directory
- Masquerading as Linux Crond Process
- Potential Defense Evasion Via Binary Rename
- Potential Defense Evasion Via Rename Of Highly Relevant Binaries
- Potential Homoglyph Attack Using Lookalike Characters
- Potential Homoglyph Attack Using Lookalike Characters in Filename
- Potential PendingFileRenameOperations Tampering
- Potential WerFault ReflectDebugger Registry Value Abuse
- Ps.exe Renamed SysInternals Tool
- PUA - Potential PE Metadata Tamper Using Rcedit
- Remote Access Tool - Renamed MeshAgent Execution - MacOS
- Remote Access Tool - Renamed MeshAgent Execution - Windows
- Renamed BrowserCore.EXE Execution
- Renamed Jusched.EXE Execution
- Renamed Msdt.EXE Execution
- Renamed Office Binary Execution
- Renamed Powershell Under Powershell Channel
- Renamed ProcDump Execution
- Renamed Schtasks Execution
- Suspicious Copy From or To System Directory
- Suspicious Download From Direct IP Via Bitsadmin
- Suspicious Download From File-Sharing Website Via Bitsadmin
- Suspicious Start-Process PassThru
- Windows Processes Suspicious Parent Directory
Elastic 11 rules
- Microsoft Build Engine Using an Alternate Name
- Potential Credential Access via Renamed COM+ Services DLL
- Potential Data Exfiltration via Rclone
- Potential Kubectl Masquerading via Unexpected Process
- Renamed Automation Script Interpreter
- Renamed Utility Executed with Short Program Name
- Suspicious Microsoft Antimalware Service Execution
- Suspicious Microsoft Diagnostics Wizard Execution
- Suspicious Process Execution via Renamed PsExec Executable
- Suspicious Renaming of ESXI Files
- System Binary Moved or Copied
Splunk 15 rules
- Execution of File with Multiple Extensions
- Rename System Utilities (Windows Event Log)
- Renamed Process (Sysmon)
- Suspicious Copy on System32
- Suspicious microsoft workflow compiler rename
- Suspicious msbuild path
- Suspicious MSBuild Rename
- System Processes Run From Unexpected Locations
- Windows DotNet Binary in Non Standard Path
- Windows InstallUtil in Non Standard Path
- Windows LOLBAS Executed As Renamed File
- Windows Process Copied from System Folder (PowerShell)
- Windows Process Copied from System Folder (Sysmon)
- Windows Process Copied from System Folder (Windows Event Log)
- Windows Renamed Powershell Execution