YARA · Trellix Advanced Research Center
TRELLIX_ARC_Ransom_Linux_Hellokitty_0721
rule to detect Linux variant of the Hello Kitty Ransomware
- Author
- Christiaan @ ATR
- Date
- 2021-07-19
- Score / Quality
- 75 / 70
What this rule detects
rule to detect Linux variant of the Hello Kitty Ransomware
Associated malware family: HelloKitty.
It defines 11 patterns (11 text, 0 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
rule TRELLIX_ARC_Ransom_Linux_Hellokitty_0721 : RANSOMWARE FILE
{
meta:
= "rule to detect Linux variant of the Hello Kitty Ransomware"
= "Christiaan @ ATR"
= "097b02e7-93d8-5d4f-9964-7b660b3cd7b9"
= "2021-07-19"
= "2021-07-19"
= "https://github.com/advanced-threat-research/Yara-Rules/"
= "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/ransomware/RANSOM_Linux_HelloKitty0721.yar#L1-L28"
= "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/LICENSE"
= "ca607e431062ee49a21d69d722750e5edbd8ffabcb54fa92b231814101756041"
= "556e5cb5e4e77678110961c8d9260a726a363e00bf8d278e5302cb4bfccc3eed"
= "77a3809df4c7c591a855aaecd702af62935952937bb81661aa7f68e64dcf4fb4"
= 75
= 70
= "RANSOMWARE, FILE"
= "v1"
= "ransomware"
= "Ransom:Linux/HelloKitty"
strings:
$v1 = "esxcli vm process kill -t=force -w=%d" fullword ascii
$v2 = "esxcli vm process kill -t=hard -w=%d" fullword ascii
$v3 = "esxcli vm process kill -t=soft -w=%d" fullword ascii
$v4 = "error encrypt: %s rename back:%s" fullword ascii
$v5 = "esxcli vm process list" fullword ascii
$v6 = "Total VM run on host:" fullword ascii
$v7 = "error lock_exclusively:%s owner pid:%d" fullword ascii
$v8 = "Error open %s in try_lock_exclusively" fullword ascii
$v9 = "Mode:%d Verbose:%d Daemon:%d AESNI:%d RDRAND:%d " fullword ascii
$v10 = "pthread_cond_signal() error" fullword ascii
$v11 = "ChaCha20 for x86_64, CRYPTOGAMS by <appro@openssl.org>" fullword ascii
condition:
( uint16( 0 ) == 0x457f and filesize < 200KB and ( 8 of them ) ) or ( all of them )
}
Strings (11 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $v1 | text | "esxcli vm process kill -t=force -w=%d" | fullword ascii |
| $v2 | text | "esxcli vm process kill -t=hard -w=%d" | fullword ascii |
| $v3 | text | "esxcli vm process kill -t=soft -w=%d" | fullword ascii |
| $v4 | text | "error encrypt: %s rename back:%s" | fullword ascii |
| $v5 | text | "esxcli vm process list" | fullword ascii |
| $v6 | text | "Total VM run on host:" | fullword ascii |
| $v7 | text | "error lock_exclusively:%s owner pid:%d" | fullword ascii |
| $v8 | text | "Error open %s in try_lock_exclusively" | fullword ascii |
| $v9 | text | "Mode:%d Verbose:%d Daemon:%d AESNI:%d RDRAND:%d " | fullword ascii |
| $v10 | text | "pthread_cond_signal() error" | fullword ascii |
| $v11 | text | "ChaCha20 for x86_64, CRYPTOGAMS by <appro@openssl.org>" | fullword ascii |
Condition
( uint16( 0 ) == 0x457f and filesize < 200KB and ( 8 of them ) ) or ( all of them )In plain words (Heuristic)
- The file must be smaller than 200KB (a cheap guard that skips large files).
- All patterns in the rule must match.
- At least 8 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.
Sample hashes
Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).
- ca607e431062ee49a21d69d722750e5edbd8ffabcb54fa92b231814101756041
- 556e5cb5e4e77678110961c8d9260a726a363e00bf8d278e5302cb4bfccc3eed
Licence & attribution
Author: Christiaan @ ATR
Source repository: Trellix Advanced Research Center @ 1919562a59
Licence: Apache License 2.0 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 097b02e7-93d8-5d4f-9964-7b660b3cd7b9
Metadata
| Rule_Version | v1 |
|---|---|
| malware_type | ransomware |
| malware_family | Ransom:Linux/HelloKitty |
Tags:RANSOMWAREFILE
Related rules
- MalwareMalpedia signator rules· Felix Bilstein - yara-signator at cocacoding dot com· 2026-05-04
- MalwareditekSHen detection· ditekSHen· 2020-11-06
- ARKBIRD_SOLG_RAN_ELF_Hellokitty_Aug_2021_1Metadata onlyMalwareArkbird SOLG (DailyIOC)· Arkbird_SOLG· 2021-08-14
- APT / threat actorSignature Base (Florian Roth / Nextron)· Florian Roth (Nextron Systems)· 2021-05-01
- APT / threat actorSignature Base (Florian Roth / Nextron)· Florian Roth (Nextron Systems)· 2021-05-01
- MalwareTrellix Advanced Research Center· Marc Rivero | McAfee ATR Team· 2026-09-01
- MalwareTrellix Advanced Research Center· Marc Rivero | McAfee ATR Team· 2026-09-01
- MalwareTrellix Advanced Research Center· McAfee ATR team· 2026-09-01