Sublime Security high experimental mql

Headers: Self-sender using Microsoft CompAuth bypass with credential theft content

Detects messages sent to self or invalid domains containing credential theft content that bypass Microsoft's CompAuth while failing both SPF and DMARC authentication checks.

View Source

Detection Logic

type.inbound
// self sender
and length(recipients.to) == 1
and length(recipients.cc) == 0
and length(recipients.bcc) == 0
and (
  sender.email.email == recipients.to[0].email.email
  or recipients.to[0].email.domain.valid == false
)
// cred theft
and any(ml.nlu_classifier(body.current_thread.text).intents,
        .name == "cred_theft" and .confidence != "low"
)
// microsoft compauth pass, but spf and dmarc fail
and any(headers.hops, any(.fields, strings.icontains(.value, 'compauth=pass')))
and not coalesce(headers.auth_summary.dmarc.pass, false)
and not coalesce(headers.auth_summary.spf.pass, false)

Field Validations

Loading…

Comments (0)

Loading comments...