PowerShell Classic bXOR Operator Usage in Command Line

Identifies PowerShell classic executions from ConsoleHost using the -bxor operator in the command line.

FreeReviewedSigma · Low · v5

Product: windows
Category: ps_classic_start
Author: Teymur Kheirkhabarov, Harish Segar (SigmaHQ), DRL 1.1
Published: 2020-06-29
Updated: 2026-07-31

ATT&CK techniques

Execution

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

What it detects

This rule flags PowerShell Classic command lines executed via ConsoleHost that include the substring " -bxor ", indicating use of the bitwise XOR operator. Attackers may use XOR to obfuscate or transform payloads to reduce the visibility of malicious content. It relies on Windows PowerShell Classic process start telemetry with access to the full CommandLine value and the HostName field to confirm the execution context.

Reporting behind it

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PowerShell Classic bXOR Operator Usage in Command Line

Pivot detection · T1059.001 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

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

powershell-classic-detect-bxor-operator-in-consolehost-command-line-812837bb

title: PowerShell Classic bXOR Operator Usage in Command Line
id: 62691060-8e8d-4336-a7f6-6df32c3a0c24
status: test
description: This rule flags PowerShell Classic command lines executed via ConsoleHost that include the substring " -bxor ", indicating use of the bitwise XOR operator. Attackers may use XOR to obfuscate or transform payloads to reduce the visibility of malicious content. It relies on Windows PowerShell Classic process start telemetry with access to the full CommandLine value and the HostName field to confirm the execution context.
references:
  - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=46
  - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_arithmetic_operators?view=powershell-5.1
  - https://github.com/SigmaHQ/sigma/blob/master/rules-threat-hunting/windows/powershell/powershell_classic/posh_pc_bxor_operator_usage.yml
author: Teymur Kheirkhabarov, Harish Segar, Huntrule Team
date: 2020-06-29
modified: 2024-12-11
tags:
  - attack.execution
  - attack.t1059.001
  - detection.threat-hunting
logsource:
  product: windows
  category: ps_classic_start
detection:
  selection:
    Data|contains|all:
      - HostName=ConsoleHost
      - " -bxor "
  condition: selection
falsepositives:
  - Unknown
level: low
license: DRL-1.1
related:
  - id: 812837bb-b17f-45e9-8bd0-0ec35d2e3bd6
    type: derived

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