YARA · SEKOIA.IO Community
SEKOIA_Rootkit_Win_Purplefox_Svchost_Txt
Detects Purple Fox payloads used during end-2021 and 2022 campaigns based on characteristics shared by TrendMicro details.
- Author
- Sekoia.io
- Date
- 2022-03-28
- Modified
- 2024-12-19
- Score / Quality
- 75 / 80
What this rule detects
Detects Purple Fox payloads used during end-2021 and 2022 campaigns based on characteristics shared by TrendMicro details.
Associated malware family: Purplefox.
It defines 6 patterns (6 text, 0 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
rule SEKOIA_Rootkit_Win_Purplefox_Svchost_Txt : FILE
{
meta:
= "Detects Purple Fox payloads used during end-2021 and 2022 campaigns based on characteristics shared by TrendMicro details."
= "Sekoia.io"
= "e992d574-6a44-4bea-97e2-6d5579ce8d02"
= "2022-03-28"
= "2024-12-19"
= "https://www.trendmicro.com/en_us/research/22/c/purple-fox-uses-new-arrival-vector-and-improves-malware-arsenal.html"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/rootkit_win_purplefox_svchost_txt.yar#L1-L22"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
= "a1de949cb2e898ed031f5c796f7152af12dfae5431dfaf269f25ebe72f0ae004"
= 75
= 80
= "FILE"
= "1.0"
= "TLP:CLEAR"
strings:
$str0 = "C:\\ProgramData\\dll.dll,luohua" wide
$str1 = "C:\\ProgramData\\7z.exe" wide
$str2 = "F:\\hidden-master\\x64\\Debug\\QAssist.pdb" ascii
$str3 = "F:\\Root\\sources\\MedaiUpdateV8\\Release\\MedaiUpdateV8.pdb" ascii
$str4 = "cmd.exe /c RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 255" ascii
$str5 = "del /s /f %appdata%\\Mozilla\\Firefox\\Profiles\\*.db" ascii
condition:
4 of ( $str* ) and filesize > 7000KB and filesize < 9500KB
}
Strings (6 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $str0 | text | "C:\\ProgramData\\dll.dll,luohua" | wide |
| $str1 | text | "C:\\ProgramData\\7z.exe" | wide |
| $str2 | text | "F:\\hidden-master\\x64\\Debug\\QAssist.pdb" | ascii |
| $str3 | text | "F:\\Root\\sources\\MedaiUpdateV8\\Release\\MedaiUpdateV8.pdb" | ascii |
| $str4 | text | "cmd.exe /c RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 255" | ascii |
| $str5 | text | "del /s /f %appdata%\\Mozilla\\Firefox\\Profiles\\*.db" | ascii |
Condition
4 of ( $str* ) and filesize > 7000KB and filesize < 9500KBIn plain words (Heuristic)
- The file must be smaller than 9500KB (a cheap guard that skips large files).
- The file must be larger than 7000KB.
- At least 4 patterns in ( $str* ) 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.
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: e992d574-6a44-4bea-97e2-6d5579ce8d02
Metadata
| version | 1.0 |
|---|---|
| classification | TLP:CLEAR |
Tags:FILE
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