Detection rules › Sublime MQL
Attachment with unscannable encrypted zip
Recursively scans files and archives to detect embedded ZIP files that are encrypted and could not be opened/scanned.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | Malware/Ransomware |
| Tactics and techniques | Encryption, Evasion |
Event coverage
| Message attribute |
|---|
| attachments (collection) |
| type |
Rule body MQL
type.inbound
and any(attachments,
(.file_type == "zip" or .file_extension == "zip")
and any(file.explode(.),
any(.flavors.yara, . == 'encrypted_zip')
and .scan.encrypted_zip.cracked_password == null
)
)
Detection logic
Scope: inbound message.
Recursively scans files and archives to detect embedded ZIP files that are encrypted and could not be opened/scanned.
- inbound message
any of
attachmentswhere all hold:any of:
- .file_type is 'zip'
- .file_extension is 'zip'
any of
file.explode(.)where all hold:any of
.flavors.yarawhere:- . is 'encrypted_zip'
- .scan.encrypted_zip.cracked_password is None
Inspects: attachments[].file_extension, attachments[].file_type, type.inbound. Sensors: file.explode.
Indicators matched (3)
| Field | Match | Value |
|---|---|---|
attachments[].file_type | equals | zip |
attachments[].file_extension | equals | zip |
file.explode(attachments[])[].flavors.yara[] | equals | encrypted_zip |