YARA · SEKOIA.IO Community
SEKOIA_Launcher_Win_Mistcloak
Detect the MISTCLOAK malware
- Author
- Sekoia.io
- Date
- 2022-12-01
- Modified
- 2024-12-19
- Score / Quality
- 75 / 80
What this rule detects
Detect the MISTCLOAK malware
Associated malware family: Mistcloak.
Targets: Windows PE.
It defines 5 patterns (5 text, 0 hex, 0 regex). 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
Includes the imports needed to compile it on its own.
import "pe"
import "hash"
rule SEKOIA_Launcher_Win_Mistcloak : FILE
{
meta:
= "Detect the MISTCLOAK malware"
= "Sekoia.io"
= "3dbf5efa-d77c-436a-a080-9ac58a78425f"
= "2022-12-01"
= "2024-12-19"
= "https://github.com/SEKOIA-IO/Community"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/launcher_win_mistcloak.yar#L4-L33"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
= "fc2731ec4e2917be1ad169908ed324931a93f6998aee606319750b5cc02715e2"
= 75
= 80
= "FILE"
= "1.0"
= "TLP:CLEAR"
strings:
$ = "\\usb.ini"
$ = "autorun.inf\\Protection for Autorun\\System Volume Information"
$ = "G:\\project\\APT\\U"
$ = "\\new\\u2ec\\Release\\u2ec.pdb"
$ = "CheckUsbService"
condition:
uint16( 0 ) == 0x5A4D and 3 of them or hash.md5 ( pe.rich_signature.clear_data ) == "0f5082fd7ddd1950fa332a8fa4df052f" or for any i in ( 0 .. pe.number_of_sections -1 ) : ( hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "0ceac625db1e8405efe45d47486e9e2d" or hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "6968e6ac7b9c1dfbf40a0b3c4f6f4157" or hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "e6ed2da41f74e948cba7a002c41c6af5" )
}
Strings (5 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $ | text | "\\usb.ini" | |
| $ | text | "autorun.inf\\Protection for Autorun\\System Volume Information" | |
| $ | text | "G:\\project\\APT\\U" | |
| $ | text | "\\new\\u2ec\\Release\\u2ec.pdb" | |
| $ | text | "CheckUsbService" |
Condition
uint16( 0 ) == 0x5A4D and 3 of them or hash.md5 ( pe.rich_signature.clear_data ) == "0f5082fd7ddd1950fa332a8fa4df052f" or for any i in ( 0 .. pe.number_of_sections -1 ) : ( hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "0ceac625db1e8405efe45d47486e9e2d" or hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "6968e6ac7b9c1dfbf40a0b3c4f6f4157" or hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "e6ed2da41f74e948cba7a002c41c6af5" )In plain words (Heuristic)
- The file must start with “MZ” — a Windows executable (PE).
- At least 3 patterns in the rule must match.
- A for-loop checks a property over several matches or items.
- Uses the hash module.
- Uses the pe module.
- Compares a hash of the file or a part of it.
- Checks PE sections (names, count or properties).
Test this rule in your browser
Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.
References
Licence & attribution
Author: Sekoia.io
Source repository: SEKOIA.IO Community @ a438a5901a
Licence: Detection Rule License 1.1 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 3dbf5efa-d77c-436a-a080-9ac58a78425f
Metadata
| version | 1.0 |
|---|---|
| classification | TLP:CLEAR |
Tags:FILE
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