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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_OBFUSC_Powershell_True_Jun20_1

Detects indicators often found in obfuscated PowerShell scripts. Note: This detection is based on common characteristics typically associated with the mentioned threats, must be considered a clue and does not conclusively prove maliciousness.

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2020-06-27
Modified
2025-02-12
Score / Quality
75 / 85

What this rule detects

Detects indicators often found in obfuscated PowerShell scripts. Note: This detection is based on common characteristics typically associated with the mentioned threats, must be considered a clue and does not conclusively prove maliciousness.

It defines 7 patterns (7 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
susp-obfusc-powershell-true-jun20-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_OBFUSC_Powershell_True_Jun20_1 : FILE
{
	meta:
		description = "Detects indicators often found in obfuscated PowerShell scripts. Note: This detection is based on common characteristics typically associated with the mentioned threats, must be considered a clue and does not conclusively prove maliciousness."
		author = "Florian Roth (Nextron Systems)"
		id = "e9bb870b-ad72-57d3-beff-2f84a81490eb"
		date = "2020-06-27"
		modified = "2025-02-12"
		reference = "https://github.com/corneacristian/mimikatz-bypass/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_powershell_obfuscation.yar#L57-L75"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "8f33762e6e93fcf6b423b34eb1abefae2ae91b51048303947f7c1601823630d7"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$ = "${t`rue}" ascii nocase
		$ = "${tr`ue}" ascii nocase
		$ = "${tru`e}" ascii nocase
		$ = "${t`ru`e}" ascii nocase
		$ = "${tr`u`e}" ascii nocase
		$ = "${t`r`ue}" ascii nocase
		$ = "${t`r`u`e}" ascii nocase

	condition:
		filesize < 6000KB and 1 of them
}

Strings (7 patterns)

IdentifierTypeValueModifiers
$text"${t`rue}"ascii nocase
$text"${tr`ue}"ascii nocase
$text"${tru`e}"ascii nocase
$text"${t`ru`e}"ascii nocase
$text"${tr`u`e}"ascii nocase
$text"${t`r`ue}"ascii nocase
$text"${t`r`u`e}"ascii nocase

Condition

filesize < 6000KB and 1 of them

In plain words (Heuristic)

  • The file must be smaller than 6000KB (a cheap guard that skips large files).
  • At least 1 patterns in the rule must match.

Test this rule in your browser

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Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

References

Licence & attribution

Author: Florian Roth (Nextron Systems)

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: e9bb870b-ad72-57d3-beff-2f84a81490eb

Tags:FILE

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