sublimemediumRule

Service abuse: FileMail callback scam

Detects inbound messages from FileMail's no-reply address where the first line of the email body is classified with high confidence as a callback scam using natural language understanding. Attackers leverage legitimate file sharing services to deliver fraudulent messages that instruct recipients to call a phone number, often impersonating tech support or financial institutions.

MITRE ATT&CK

T1566.003 T1598 T1566

initial-access

Detection Query

type.inbound
and sender.email.email == "no-reply@filemail.com"
and any(ml.nlu_classifier(regex.extract(body.current_thread.text,
                                        '^(?P<first_line>[^\n]+)\n'
                          )[0].named_groups["first_line"]
        ).intents,
        .name == "callback_scam" and .confidence == "high"
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Service abuse: FileMail callback scam"
description: "Detects inbound messages from FileMail's no-reply address where the first line of the email body is classified with high confidence as a callback scam using natural language understanding. Attackers leverage legitimate file sharing services to deliver fraudulent messages that instruct recipients to call a phone number, often impersonating tech support or financial institutions."
type: "rule"
severity: "medium"
source: |
  type.inbound
  and sender.email.email == "no-reply@filemail.com"
  and any(ml.nlu_classifier(regex.extract(body.current_thread.text,
                                          '^(?P<first_line>[^\n]+)\n'
                            )[0].named_groups["first_line"]
          ).intents,
          .name == "callback_scam" and .confidence == "high"
  )
  
  
attack_types:
  - "Callback Phishing"
tactics_and_techniques:
  - "Social engineering"
  - "Free file host"
  - "Out of band pivot"
detection_methods:
  - "Natural Language Understanding"
  - "Sender analysis"
  - "Content analysis"
id: "9305a806-2c58-5bd7-8c96-c8b2b74d9961"