Detection rules › Sublime MQL
Attachment: PDF generated with wkhtmltopdf tool and default title
Detects PDF attachments that were generated using the wkhtmltopdf conversion tool, which converts HTML/CSS to PDF. This tool is commonly used by attackers to create legitimate-looking PDF documents from web content for social engineering purposes.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | BEC/Fraud, Callback Phishing, Credential Phishing, Malware/Ransomware |
| Tactics and techniques | PDF, Evasion |
Event coverage
| Message attribute |
|---|
| attachments (collection) |
| type |
Rule body MQL
type.inbound
and any(filter(attachments, .file_extension == "pdf"),
strings.istarts_with(beta.parse_exif(.).producer, "Qt")
and strings.icontains(beta.parse_exif(.).creator, "wkhtmltopdf")
and beta.parse_exif(.).title == "Document"
)
Detection logic
Scope: inbound message.
Detects PDF attachments that were generated using the wkhtmltopdf conversion tool, which converts HTML/CSS to PDF. This tool is commonly used by attackers to create legitimate-looking PDF documents from web content for social engineering purposes.
- inbound message
any of
filter(attachments)where all hold:- beta.parse_exif(.).producer starts with 'Qt'
- beta.parse_exif(.).creator contains 'wkhtmltopdf'
- beta.parse_exif(.).title is 'Document'
Inspects: attachments[].file_extension, type.inbound. Sensors: beta.parse_exif, strings.icontains, strings.istarts_with.
Indicators matched (3)
| Field | Match | Value |
|---|---|---|
attachments[].file_extension | equals | pdf |
strings.istarts_with | prefix | Qt |
strings.icontains | substring | wkhtmltopdf |