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SEKOIA_Malware_Remcom_Strings

Detects RemCom based on strings

MalwareRemcomSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2022-08-30
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects RemCom based on strings

Associated malware family: Remcom.

Targets: Windows PE.

It defines 6 patterns (6 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-remcom-strings.yarDetection Rule License 1.1
rule SEKOIA_Malware_Remcom_Strings : FILE
{
	meta:
		description = "Detects RemCom based on strings"
		author = "Sekoia.io"
		id = "7a56d55a-2f35-41ef-b7af-259baf215a62"
		date = "2022-08-30"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/malware_remcom_strings.yar#L1-L22"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "a46bb87bf4722303d33707afb19c8d4f209b98a88552363363520536911469ae"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = "RemComSvc"
		$ = "RemCom_stderr"
		$ = "RemCom_stdin"
		$ = "\\\\.\\pipe\\%s%s%d"
		$ = "RemCom_stdout"
		$ = "\\\\.\\pipe\\RemCom_communicaton"

	condition:
		uint16be( 0 ) == 0x4d5a and filesize < 1MB and 4 of them
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$text"RemComSvc"
$text"RemCom_stderr"
$text"RemCom_stdin"
$text"\\\\.\\pipe\\%s%s%d"
$text"RemCom_stdout"
$text"\\\\.\\pipe\\RemCom_communicaton"

Condition

uint16be( 0 ) == 0x4d5a and filesize < 1MB and 4 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 1MB (a cheap guard that skips large files).
  • At least 4 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: 7a56d55a-2f35-41ef-b7af-259baf215a62

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE