PowerShell Obfuscation via Negative Index String Reversal
Detects PowerShell scripts that uses negative index ranges (for example, $var[-1..0]) to reverse strings or arrays and rebuild content at runtime. Attackers use index reversal to reconstruct hidden commands or…
Description
Detects PowerShell scripts that uses negative index ranges (for example, $var[-1..0]) to reverse strings or arrays and rebuild content at runtime. Attackers use index reversal to reconstruct hidden commands or payloads and evade static analysis and AMSI.
Detection logic
Its licence does not clear it for publishing here
Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.
Detection requirements
- Platform
- ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows
The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
No references are available for this detection.
From the source
- At source
- Open at source
- Upstream identifier
- 9edd1804-83c7-4e48-b97d-c776b4c97564
- Tagged by the source as
- Data Source: PowerShell LogsDomain: EndpointNoise: MediumOS: WindowsPerformance: NormalPlatform: WindowsResources: Investigation GuideRule Type: ES|QLTactic: Defense EvasionThreat: Script-Based ExecutionUse Case: Threat Detection
Licence
- Published under
- Elastic License 2.0Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Oct 6, 2026
- Version
- 4