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SEKOIA_Hacktool_Ntospy_Strings

Detects Ntospy based on strings

Hack toolNtospySEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2023-12-05
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects Ntospy based on strings

Associated malware family: Ntospy.

Targets: Windows PE.

It defines 3 patterns (2 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
hacktool-ntospy-strings.yarDetection Rule License 1.1
rule SEKOIA_Hacktool_Ntospy_Strings : FILE
{
	meta:
		description = "Detects Ntospy based on strings"
		author = "Sekoia.io"
		id = "c3281666-6a31-4718-a9c0-82944c6fdcb0"
		date = "2023-12-05"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/hacktool_ntospy_strings.yar#L1-L19"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "e5bd963419e515d65a03592051822fd801f4a21d54cdb18d408556c4bfef78f5"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = "NPGetCaps"
		$ = "NPLogonNotify"
		$ = {43 00 3A 00 5C 00 [10-150] 00 2E 00 6D 00 73 00 75}

	condition:
		uint16be( 0 ) == 0x4d5a and filesize < 300KB and all of them
}

Strings (3 patterns)

IdentifierTypeValueModifiers
$text"NPGetCaps"
$text"NPLogonNotify"
$hex{43 00 3A 00 5C 00 [10-150] 00 2E 00 6D 00 73 00 75}

Condition

uint16be( 0 ) == 0x4d5a and filesize < 300KB and all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 300KB (a cheap guard that skips large files).
  • All patterns in the rule must match.

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References

Licence & attribution

Author: Sekoia.io

Source repository: SEKOIA.IO Community @ a438a5901a

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: c3281666-6a31-4718-a9c0-82944c6fdcb0

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE

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