Sigma rule: bXOR Operator Usage In PowerShell Command Line - PowerShell Classic

Rule

Title

bXOR Operator Usage In PowerShell Command Line - PowerShell Classic

Status

test

Level

low

Author

Teymur Kheirkhabarov, Harish Segar

Date

2020-06-29

Modified

2024-12-11

File

rules-threat-hunting/windows/powershell/powershell_classic/posh_pc_bxor_operator_usage.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects powershell execution with that make use of to the bxor (Bitwise XOR).
Attackers might use as an alternative obfuscation method to Base64 encoded commands.
Investigate the CommandLine and process tree to determine if the activity is malicious.

Log source

product

windows

category

ps_classic_start

Detection

selection:
    Data|contains|all:
        - 'HostName=ConsoleHost'
        - ' -bxor '
condition: selection

False positives (as the rule lists them)

• Unknown

Tags

• attack.execution
• attack.t1059.001
• detection.threat-hunting

MITRE ATT&CK ids this rule names

• T1059.001

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

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-threat-hunting/windows/powershell/powershell_classic/posh_pc_bxor_operator_usage.yml