Detection rules › Sublime MQL

Attachment: PDF with personal Microsoft OneNote URL

Severity
medium
Type
rule
Source
github.com/sublime-security/sublime-rules

Detects PDF attachments containing a sharepoint URL referencing the senders personal OneNote.

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

CategoryValues
Attack typesCredential Phishing
Tactics and techniquesPDF, Social engineering

Event coverage

Rule body MQL

type.inbound
and length(filter(attachments, .file_type == "pdf")) >= 1
and any(attachments,
        .file_type == "pdf"
        and any(file.explode(.),
                any(.scan.url.urls,
                    strings.icontains(.path,
                                      strings.concat("/:o:/p/",
                                                     sender.email.local_part
                                      )
                    )
                    or strings.icontains(.path, "/:o:/g/personal/")
                )
        )
)

Detection logic

Scope: inbound message.

Detects PDF attachments containing a sharepoint URL referencing the senders personal OneNote.

  1. inbound message
  2. length(filter(attachments, .file_type == 'pdf')) ≥ 1
  3. any of attachments where all hold:
    • .file_type is 'pdf'
    • any of file.explode(.) where:
      • any of .scan.url.urls where any holds:
        • strings.icontains(.path)
        • .path contains '/:o:/g/personal/'

Inspects: attachments[].file_type, sender.email.local_part, type.inbound. Sensors: file.explode, strings.concat, strings.icontains.

Indicators matched (2)

FieldMatchValue
attachments[].file_typeequalspdf
strings.icontainssubstring/:o:/g/personal/