Skip to content

YARA · Malpedia signator rules

MALPEDIA_Win_R77_Auto

autogenerated rule brought to you by yara-signator

MalwareR77Malpedia signator rulesCreative Commons Attribution-ShareAlike 4.0Compiles with YARA-X
Author
Felix Bilstein - yara-signator at cocacoding dot com
Date
2026-05-04
Modified
2026-05-18
Score / Quality
75 / 75

What this rule detects

autogenerated rule brought to you by yara-signator

Associated malware family: R77.

It defines 14 patterns (0 text, 14 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

win-r77-auto.yarCreative Commons Attribution-ShareAlike 4.0
rule MALPEDIA_Win_R77_Auto : FILE
{
	meta:
		description = "autogenerated rule brought to you by yara-signator"
		author = "Felix Bilstein - yara-signator at cocacoding dot com"
		id = "37f7a978-a7e5-5410-9083-a09fa21c8e1f"
		date = "2026-05-04"
		modified = "2026-05-18"
		reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.r77"
		source_url = "https://github.com/malpedia/signator-rules//blob/c901f97b7df03e41917da74c2a84b04c227316c2/rules/win.r77_auto.yar#L1-L150"
		license_url = "N/A"
		logic_hash = "1736f21ff7c691211d3e9dcd35bc840c7e9e551945dbc1deeab3d32e6e1975e5"
		score = 75
		quality = 75
		tags = "FILE"
		version = "1"
		tool = "yara-signator v0.6.0"
		signator_config = "callsandjumps;datarefs;binvalue"
		malpedia_rule_date = "20260422"
		malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
		malpedia_version = "20260504"
		malpedia_license = "CC BY-SA 4.0"
		malpedia_sharing = "TLP:WHITE"

	strings:
		$sequence_0 = { 740c 8b4f0c e8???????? 85c0 }
		$sequence_1 = { 740b 8b0f e8???????? 85c0 }
		$sequence_2 = { 83f866 0f85a9000000 b901000000 6bd103 8b4508 0fb60c10 }
		$sequence_3 = { 488d050a440100 483bc8 7406 e8???????? 90 8b0b e8???????? }
		$sequence_4 = { 8bd3 b9???????? e8???????? a3???????? 5f }
		$sequence_5 = { 8b4d10 0fb61401 83e21f 8855ff }
		$sequence_6 = { ff752c ff7528 56 ff7520 53 }
		$sequence_7 = { c1cf0d 803b61 8d42e0 0f4cc2 03f8 43 6685f6 }
		$sequence_8 = { 4883ec20 488d05df750000 488bd9 483bc8 7417 8b815c010000 }
		$sequence_9 = { 488d3d6cb6feff 488bcf e8???????? 85c0 }
		$sequence_10 = { e8???????? e9???????? 493bff 7508 41bc06000080 eb21 83eb01 }
		$sequence_11 = { c745e806000000 e9???????? 8b4df4 034dec 8b55fc }
		$sequence_12 = { 0f85a9000000 4885f6 0f84a0000000 8b4704 }
		$sequence_13 = { 48894328 e8???????? 48894330 e8???????? 48894338 488d153fc30100 }

	condition:
		7 of them and filesize < 350208
}

Strings (14 patterns)

IdentifierTypeValueModifiers
$sequence_0hex{ 740c 8b4f0c e8???????? 85c0 }
$sequence_1hex{ 740b 8b0f e8???????? 85c0 }
$sequence_2hex{ 83f866 0f85a9000000 b901000000 6bd103 8b4508 0fb60c10 }
$sequence_3hex{ 488d050a440100 483bc8 7406 e8???????? 90 8b0b e8???????? }
$sequence_4hex{ 8bd3 b9???????? e8???????? a3???????? 5f }
$sequence_5hex{ 8b4d10 0fb61401 83e21f 8855ff }
$sequence_6hex{ ff752c ff7528 56 ff7520 53 }
$sequence_7hex{ c1cf0d 803b61 8d42e0 0f4cc2 03f8 43 6685f6 }
$sequence_8hex{ 4883ec20 488d05df750000 488bd9 483bc8 7417 8b815c010000 }
$sequence_9hex{ 488d3d6cb6feff 488bcf e8???????? 85c0 }
$sequence_10hex{ e8???????? e9???????? 493bff 7508 41bc06000080 eb21 83eb01 }
$sequence_11hex{ c745e806000000 e9???????? 8b4df4 034dec 8b55fc }
$sequence_12hex{ 0f85a9000000 4885f6 0f84a0000000 8b4704 }
$sequence_13hex{ 48894328 e8???????? 48894330 e8???????? 48894338 488d153fc30100 }

Condition

7 of them and filesize < 350208

In plain words (Heuristic)

  • The file must be smaller than 350208 (a cheap guard that skips large files).
  • At least 7 patterns in the rule must match.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

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

Open in editor

References

Licence & attribution

Author: Felix Bilstein - yara-signator at cocacoding dot com

Source repository: Malpedia signator rules @ c901f97b7d

Licence: Creative Commons Attribution-ShareAlike 4.0 (repository licence)

Original rule

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

Rule id: 37f7a978-a7e5-5410-9083-a09fa21c8e1f

Metadata

version1
toolyara-signator v0.6.0
signator_configcallsandjumps;datarefs;binvalue
malpedia_rule_date20260422
malpedia_hasha182e35da64e6d71cb55f125c4d4225196523f14
malpedia_version20260504
malpedia_licenseCC BY-SA 4.0
malpedia_sharingTLP:WHITE

Tags:FILE