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MALPEDIA_Win_Mailto_Auto

autogenerated rule brought to you by yara-signator

MalwareMailtoMalpedia 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: Mailto.

It defines 10 patterns (0 text, 10 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

win-mailto-auto.yarCreative Commons Attribution-ShareAlike 4.0
rule MALPEDIA_Win_Mailto_Auto : FILE
{
	meta:
		description = "autogenerated rule brought to you by yara-signator"
		author = "Felix Bilstein - yara-signator at cocacoding dot com"
		id = "77746f51-fc1c-50cd-a4af-268d4a5b9d6b"
		date = "2026-05-04"
		modified = "2026-05-18"
		reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.mailto"
		source_url = "https://github.com/malpedia/signator-rules//blob/c901f97b7df03e41917da74c2a84b04c227316c2/rules/win.mailto_auto.yar#L1-L134"
		license_url = "N/A"
		logic_hash = "53e3ddf0c82c6285bb2fdbc99e3b02c5febe1a13e39cac446d5a6487b03a6443"
		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 = { 56 e8???????? 83c40c 85c0 75e7 5f 5e }
		$sequence_1 = { 68dee412a3 56 894134 e8???????? 8b0d???????? 689a8f3aca 56 }
		$sequence_2 = { 5e 85c9 890f 5b 0f95c0 5f c3 }
		$sequence_3 = { c744246474000000 e8???????? 8d4c2414 51 56 8b4030 ffd0 }
		$sequence_4 = { e8???????? 83c444 6a00 6841db0100 ffb424b0000000 ffb424b0000000 e8???????? }
		$sequence_5 = { 23c8 8bc1 c1e01a 29442420 8b442424 03c1 89442424 }
		$sequence_6 = { eb08 e8???????? 8b4048 8d4c2410 51 ffd0 880437 }
		$sequence_7 = { 33d0 03743c2c 8bc3 03742424 83c704 c1c802 33d0 }
		$sequence_8 = { 8d2c8d00000000 23e9 8b4c2430 81f1ffffff03 f7d1 8bc1 8bdd }
		$sequence_9 = { ffb424d0000000 89442430 ffb424d0000000 89542438 e8???????? 6a00 6841db0100 }

	condition:
		7 of them and filesize < 180224
}

Strings (10 patterns)

IdentifierTypeValueModifiers
$sequence_0hex{ 56 e8???????? 83c40c 85c0 75e7 5f 5e }
$sequence_1hex{ 68dee412a3 56 894134 e8???????? 8b0d???????? 689a8f3aca 56 }
$sequence_2hex{ 5e 85c9 890f 5b 0f95c0 5f c3 }
$sequence_3hex{ c744246474000000 e8???????? 8d4c2414 51 56 8b4030 ffd0 }
$sequence_4hex{ e8???????? 83c444 6a00 6841db0100 ffb424b0000000 ffb424b0000000 e8???????? }
$sequence_5hex{ 23c8 8bc1 c1e01a 29442420 8b442424 03c1 89442424 }
$sequence_6hex{ eb08 e8???????? 8b4048 8d4c2410 51 ffd0 880437 }
$sequence_7hex{ 33d0 03743c2c 8bc3 03742424 83c704 c1c802 33d0 }
$sequence_8hex{ 8d2c8d00000000 23e9 8b4c2430 81f1ffffff03 f7d1 8bc1 8bdd }
$sequence_9hex{ ffb424d0000000 89442430 ffb424d0000000 89542438 e8???????? 6a00 6841db0100 }

Condition

7 of them and filesize < 180224

In plain words (Heuristic)

  • The file must be smaller than 180224 (a cheap guard that skips large files).
  • At least 7 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: 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: 77746f51-fc1c-50cd-a4af-268d4a5b9d6b

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