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SEKOIA_Downloader_Win_Fake_Tor_Browser

Detect fake TOR browser used to spy Chinese TOR users

MalwareSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X (with warnings)
Author
Sekoia.io
Date
2022-10-05
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detect fake TOR browser used to spy Chinese TOR users

Targets: Windows PE.

It has no patterns: the condition alone decides (modules, file properties or other rules). YARA modules used: pe, hash.

YARA-X says: warning[deprecated_field]: field `number_of_sections` is deprecated

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

Includes the imports needed to compile it on its own.

downloader-win-fake-tor-browser.yarDetection Rule License 1.1
import "pe"
import "hash"

rule SEKOIA_Downloader_Win_Fake_Tor_Browser
{
	meta:
		description = "Detect fake TOR browser used to spy Chinese TOR users"
		author = "Sekoia.io"
		id = "6b070ba6-490b-43c2-9a01-65812d829eeb"
		date = "2022-10-05"
		modified = "2024-12-19"
		reference = "https://securelist.com/onionpoison-infected-tor-browser-installer-youtube/107627/"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/downloader_win_fake_tor_browser.yar#L4-L18"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "5fe60673e54a6904f4fd068b04b950b895b18e7766d2e7343eae2b1bba9591f9"
		score = 75
		quality = 80
		tags = ""
		version = "1.0"
		classification = "TLP:CLEAR"

	condition:
		for any i in ( 0 .. pe.number_of_sections -1 ) : ( hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "7172f95f934574be95c0250fb42b8f51" )
}

Condition

for any i in ( 0 .. pe.number_of_sections -1 ) : ( hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "7172f95f934574be95c0250fb42b8f51" )

In plain words (Heuristic)

  • A for-loop checks a property over several matches or items.
  • Uses the pe module.
  • Uses the hash module.
  • Compares a hash of the file or a part of it.
  • Checks PE sections (names, count or properties).

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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: 6b070ba6-490b-43c2-9a01-65812d829eeb

Metadata

version1.0
classificationTLP:CLEAR

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