Detection rules › Sublime MQL
Attachment: Archive with pdf, txt and wsf files
Detects a known Qakbot delivery method, zip file with pdf, txt and wsf file at a depth of 1
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | Malware/Ransomware |
| Tactics and techniques | Evasion, PDF |
Event coverage
| Message attribute |
|---|
| attachments (collection) |
| type |
Rule body MQL
type.inbound
and any(attachments,
.file_extension in~ $file_extensions_common_archives
and length(distinct(filter(file.explode(.),
.depth == 1
and .flavors.mime in~ (
"application/pdf",
"text/plain"
)
),
.flavors.mime
)
) == 2
and any(file.explode(.), .depth == 1 and .file_extension == "wsf")
)
Detection logic
Scope: inbound message.
Detects a known Qakbot delivery method, zip file with pdf, txt and wsf file at a depth of 1
- inbound message
any of
attachmentswhere all hold:- .file_extension in $file_extensions_common_archives
- length(distinct(filter(file.explode(.), .depth == 1 and .flavors.mime in~ ('application/pdf', 'text/plain')), .flavors.mime)) is 2
any of
file.explode(.)where all hold:- .depth is 1
- .file_extension is 'wsf'
Inspects: attachments[].file_extension, type.inbound. Sensors: file.explode. Reference lists: $file_extensions_common_archives.
Indicators matched (3)
| Field | Match | Value |
|---|---|---|
file.explode(attachments[])[].flavors.mime | member | application/pdf |
file.explode(attachments[])[].flavors.mime | member | text/plain |
file.explode(attachments[])[].file_extension | equals | wsf |