Detection rules › Sublime MQL
Attachment: PDF with split QR code
Detects PDF attachments containing split QR codes positioned close together, a technique used to evade detection while maintaining QR code functionality for credential theft.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | Credential Phishing |
| Tactics and techniques | Evasion, PDF, QR code |
Event coverage
| Message attribute |
|---|
| attachments (collection) |
| type |
Rule body MQL
type.inbound
and any(filter(attachments, .file_type == "pdf"),
any(file.explode(.),
any(.scan.yara.matches,
// yara rules match on "split" QR codes that are 290x290, 300x300, 370x370 and placed close to eachtoher in the PDF
strings.istarts_with(.name, 'Phishing_PDF_Split_QR_Code_Pair')
)
)
)
Detection logic
Scope: inbound message.
Detects PDF attachments containing split QR codes positioned close together, a technique used to evade detection while maintaining QR code functionality for credential theft.
- inbound message
any of
filter(attachments)where:any of
file.explode(.)where:any of
.scan.yara.matcheswhere:- .name starts with 'Phishing_PDF_Split_QR_Code_Pair'
Inspects: attachments[].file_type, type.inbound. Sensors: file.explode, strings.istarts_with.
Indicators matched (2)
| Field | Match | Value |
|---|---|---|
attachments[].file_type | equals | pdf |
strings.istarts_with | prefix | Phishing_PDF_Split_QR_Code_Pair |