YARA · Trellix Advanced Research Center
TRELLIX_ARC_Wannaren_Ransomware
Rule to detect WannaRen Ransomware
- Author
- McAfee ATR Team
- Date
- 2020-04-25
- Modified
- 2020-10-12
- Score / Quality
- 75 / 70
What this rule detects
Rule to detect WannaRen Ransomware
Associated malware family: WannaRen.
Targets: Windows PE.
It defines 10 patterns (0 text, 10 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
rule TRELLIX_ARC_Wannaren_Ransomware : RANSOMWARE FILE
{
meta:
= "Rule to detect WannaRen Ransomware"
= "McAfee ATR Team"
= "f4f30d12-547d-5044-a4e5-b88bf359480f"
= "2020-04-25"
= "2020-10-12"
= "https://blog.360totalsecurity.com/en/attention-you-may-have-become-a-susceptible-group-of-wannaren-ransomware/"
= "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/ransomware/RANSOM_wannaren.yar#L1-L34"
= "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/LICENSE"
= "7b364f1c854e6891c8d09766bcc9a49420e0b5b4084d74aa331ae94e2cfb7e1d"
= "0feb913b84eb0ecdda688f0cf0a5051798fe4fbce8a6ea959825985a81a6699c"
= 75
= 70
= "RANSOMWARE, FILE"
= "v1"
= "ransomware"
= "Ransom:W32/WannaRen"
= "Cybercrime"
= "Unknown"
strings:
$sq0 = { 92 93 a91c2ea521 59 334826 }
$sq1 = { d0ce 6641 c1e9c0 41 80f652 49 c1f94d }
$sq2 = { 80f8b5 4d 63c9 f9 4d 03d9 41 }
$sq3 = { 34b7 d2ea 660fbafa56 0f99c2 32d8 660fbafaed 99 }
$sq4 = { f9 f7c70012355f 35c01f5226 f9 8d8056c800b0 f6c4b2 f9 }
$sq5 = { f5 f9 44 3aeb 45 33cd 41 }
$sq6 = { 890f c0ff12 44 b4a3 ee 2b4e70 7361 }
$sq7 = { 81c502000000 6689542500 6681d97a1e 660fabe1 660fbae1a5 8b0f 8dbf04000000 }
$sq8 = { 8d13 de11 d7 677846 f1 0d8cd45f87 bb34b98f33 }
$sq9 = { 1440 4b 41 e8???????? 397c0847 }
condition:
uint16( 0 ) == 0x5a4d and filesize < 21000KB and 7 of them
}
Strings (10 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $sq0 | hex | { 92 93 a91c2ea521 59 334826 } | |
| $sq1 | hex | { d0ce 6641 c1e9c0 41 80f652 49 c1f94d } | |
| $sq2 | hex | { 80f8b5 4d 63c9 f9 4d 03d9 41 } | |
| $sq3 | hex | { 34b7 d2ea 660fbafa56 0f99c2 32d8 660fbafaed 99 } | |
| $sq4 | hex | { f9 f7c70012355f 35c01f5226 f9 8d8056c800b0 f6c4b2 f9 } | |
| $sq5 | hex | { f5 f9 44 3aeb 45 33cd 41 } | |
| $sq6 | hex | { 890f c0ff12 44 b4a3 ee 2b4e70 7361 } | |
| $sq7 | hex | { 81c502000000 6689542500 6681d97a1e 660fabe1 660fbae1a5 8b0f 8dbf04000000 } | |
| $sq8 | hex | { 8d13 de11 d7 677846 f1 0d8cd45f87 bb34b98f33 } | |
| $sq9 | hex | { 1440 4b 41 e8???????? 397c0847 } |
Condition
uint16( 0 ) == 0x5a4d and filesize < 21000KB and 7 of themIn plain words (Heuristic)
- The file must start with “MZ” — a Windows executable (PE).
- The file must be smaller than 21000KB (a cheap guard that skips large files).
- At least 7 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).
- 7b364f1c854e6891c8d09766bcc9a49420e0b5b4084d74aa331ae94e2cfb7e1d
Licence & attribution
Author: McAfee ATR Team
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: f4f30d12-547d-5044-a4e5-b88bf359480f
Metadata
| rule_version | v1 |
|---|---|
| malware_type | ransomware |
| malware_family | Ransom:W32/WannaRen |
| actor_type | Cybercrime |
| actor_group | Unknown |
Tags:RANSOMWAREFILE
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