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Description

This rule is designed to identify impersonation attempts by analyzing the display name or sender's local part for the solitary use of "X" provided the email doesn't originate from twitter.com or x.com. Natural Language Understanding (NLU) is used to check for credential theft requiring a medium-to-high confidence level for flagging.

References

No references.

Sublime Security
Created Oct 19th, 2023 • Last updated Aug 5th, 2025
Source
type.inbound
and sender.display_name =~ "x"
and sender.email.domain.root_domain not in ("twitter.com", "x.com")
and (
  any(attachments,
      .file_type in~ $file_types_images
      and any(file.explode(.),
              any(ml.nlu_classifier(.scan.ocr.raw).intents,
                  .name == "cred_theft" and .confidence != "low"
              )
      )
  )
  or any(ml.nlu_classifier(body.current_thread.text).intents,
         .name == "cred_theft" and .confidence != "low"
  )
)

// sender profile is new or outlier
and (
  profile.by_sender().prevalence in ("new", "outlier")
  or (
    profile.by_sender().any_messages_malicious_or_spam
    and not profile.by_sender().any_messages_benign
  )
  or sender.email.email in ("noreply@salesforce.com", "support@salesforce.com")
)

// negate highly trusted sender domains unless they fail DMARC authentication
and (
  (
    sender.email.domain.root_domain in $high_trust_sender_root_domains
    and not headers.auth_summary.dmarc.pass
  )
  or sender.email.domain.root_domain not in $high_trust_sender_root_domains

  // salesforce has been abused for x/twitter phishing campaigns repeatedly 
  or sender.email.domain.root_domain == "salesforce.com"
)
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