Medium Severity

BEC/Fraud: Contract or order lure with mismatched reply-to

Labels

BEC/Fraud
Spoofing
Social engineering
Header analysis
Content analysis

Description

Detects inbound messages where the reply-to address differs from the sender's address, while the subject line references a contract agreement or order with an 8-digit numeric identifier and the body text mentions an attached contract or order. This combination is a common tactic in business email compromise attempts designed to redirect replies to an attacker-controlled address.

References

No references.

Sublime Security
Created Sep 16th, 2026 • Last updated Sep 16th, 2026
Feed Source
Sublime Core Feed
Source
GitHub
type.inbound
and any(headers.reply_to, .email.email != sender.email.email)
and regex.icontains(subject.subject, '(?:contract agreement|order)_\d{8}\b')
and regex.icontains(body.current_thread.text,
                    'attached (?:contract agreement|order)'
)
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