• Sublime Core Feed
High Severity

Fake request for tax preparation

Labels

BEC/Fraud
Malware/Ransomware
Social engineering
Content analysis
Natural Language Understanding
Sender analysis

Description

Unknown sender requesting assistance with tax preparation. This is associated with known threat actor activity, TA576.

References

No references.

Sublime Security
Created Mar 27th, 2024 • Last updated Jul 16th, 2025
Feed Source
Sublime Core Feed
Source
GitHub
type.inbound
and length(body.current_thread.text) < 1250
and any(beta.ml_topic(body.current_thread.text).topics,
        .name == "Financial Communications"
)
// there are no links, all the links are to aka.ms, or an extraction from a warning banner that match the senders domain
and (
  length(body.links) == 0
  or length(filter(body.links,
                   (
                     .display_text is null
                     and .display_url.url == sender.email.domain.root_domain
                   )
                   or .href_url.domain.domain == "aka.ms"
                   or network.whois(.display_url.domain).days_old < 30
            )
  ) == length(body.links)
)
and length(attachments) == 0
and (strings.ilike(subject.subject, "*tax*") or length(subject.subject) < 15)
and strings.icontains(body.current_thread.text, "tax")
and (
  strings.like(body.current_thread.text,
               "*return*",
               "*record*",
               "*CPA*",
               "*filing*",
               "*extension*"
  )
  or strings.ilike(body.current_thread.text,
                   "*tax preparer*",
                   "*tax*processing*"
  )
)
and (
  strings.ilike(body.current_thread.text,
                "*necessary documents*",
                "*required documents*",
                "*paperwork*",
                "*in search of*",
                "*tax service*",
                "*professional help*",
                "*prepare*tax return*",
                "*service*tax return*",
                "*seeking*tax preparer*",
                "*assist*processing*tax*",
                "*schedule*call*",
                "*zoom meeting*",
                "*discuss*fees*",
                "*W2*",
                "*CPA*"
                
                
  )
  // suspicious patterns
  or (
    strings.icontains(body.current_thread.text, sender.display_name)
    and 2 of (
      (
        length(headers.reply_to) > 0
        and all(headers.reply_to,
                .email.domain.root_domain != sender.email.domain.root_domain
        )
      ),
      (
        headers.return_path.email is not null
        and headers.return_path.email != sender.email.email
      ),
      headers.return_path.domain.root_domain in ("amazonses.com")
    )
  )
)
and (
  (
    profile.by_sender().prevalence in ("new", "outlier")
    and not profile.by_sender().solicited
  )
  or (
    profile.by_sender().any_messages_malicious_or_spam
    and not profile.by_sender().any_messages_benign
  )
)
and not profile.by_sender().any_messages_benign
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