Suspicious Delayed Expansion Command Obfuscation Building PowerShell via Amatera Stealer

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
- T1027.010Command Obfuscation
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects cmd.exe using delayed variable expansion to concatenate fragmented strings that reassemble the word powershell at runtime. The Amatera Stealer 4.0.2 loader splits pow and ershell across set commands to defeat static string matching before invoking an encoded PowerShell stage. This command-line obfuscation is a strong indicator of staged stealer execution.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange

PowerShell Command-Line Obfuscation Constructs (via process_creation)

Windows PowerShell Obfuscated COM MSI Installation via WindowsInstaller.Installer

Windows Registry Set in Shell Open Command Using PowerShell Cryptography .NET Classes

PowerShell Crypto Namespace Class Invocation for Windows Process Creation

Suspicious ClickFix PowerShell Download Cradle via TAG-150 Tradecraft

Malicious PowerShell Download of FortiEndpoint Patch Masquerade via EKZ Stealer

Suspicious PowerShell Host and Locale Reconnaissance via MuddyWater Tsundere Botnet

Malicious PowerShell StreamReader WebRequest Download Cradle

Suspicious PowerShell UTF8 OutputEncoding Command Wrapper

Suspicious Delayed Expansion Command Obfuscation Building PowerShell via Amatera Stealer

Pivot detection · T1059.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

Full detection rule

Unlock this rule to view and copy it

The detection logic is included with a plan. Everything else — context, mappings and implementation details — stays free on this page.

Sign in for 3 free unlocks

Signing in gives you 3 unlocks to spend on any rule in the library. No card, and they do not expire.

Also included

Unlocked rules convert on this page — to Splunk SPL or Splunk — Raw Index SPL or Microsoft Sentinel KQL or Microsoft Sentinel ASIM ASIM KQL or Microsoft Defender XDR KQL or Elastic Security KQL or Elastic Security Lucene or Elastic Security ES|QL or CrowdStrike Falcon CQL or SentinelOne PowerQuery or Palo Alto Cortex XDR XQL or Carbon Black Cloud Platform Search or Carbon Black EDR Process Search or Google Security Operations UDM Search or IBM QRadar AQL or Sumo Logic Cloud SIEM Rules expression or Rapid7 InsightIDR LEQL or Graylog Search or OpenSearch Lucene or OpenSearch PPL PPL or Grafana Loki LogQL or SQLite SQL or Zircolite SQLite — with the log-source profile the engine picked, the field map it used, and everything it could not express. Converting a rule you have unlocked costs no further credit.

See it run on a free rule →Convert your own rule →