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Detection rules › Sublime MQL

Attachment: Encrypted PDF With Credential Harvesting Indicators

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

Detects encrypted PDF attachments containing patterns and indicators commonly associated with credential harvesting operations, identified through YARA signature analysis.

Threat classification

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

CategoryValues
Attack typesCredential Phishing
Tactics and techniquesEncryption, Evasion, PDF

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, .name in ("pdf_encrypted_cred_phish_001"))
        )
)

Detection logic

Scope: inbound message.

Detects encrypted PDF attachments containing patterns and indicators commonly associated with credential harvesting operations, identified through YARA signature analysis.

  1. inbound message
  2. any of filter(attachments) where:
    • any of file.explode(.) where:
      • any of .scan.yara.matches where:
        • .name in ('pdf_encrypted_cred_phish_001')

Inspects: attachments[].file_type, type.inbound. Sensors: file.explode.

Indicators matched (2)

FieldMatchValue
attachments[].file_typeequalspdf
file.explode(filter(attachments)[])[].scan.yara.matches[].namememberpdf_encrypted_cred_phish_001