Medium Severity

Link: Fake RFP/bid reference number lure

Labels

Credential Phishing

BEC/Fraud

Description

Flags inbound messages that reference an RFP, RFQ, bid, or proposal-style tracking code (e.g. REF-XXXX-XXXX) within a reply thread, where the embedded link points to a domain that differs from the sender's domain. This pattern is common in lures impersonating procurement, tender, or vendor bid notifications to drive recipients to an external link, and excludes messages from designated high-trust domains that pass DMARC.

References

No references.

Sublime Security

Created Aug 25th, 2026 • Last updated Aug 25th, 2026

Feed Source

Sublime Core Feed

Source

GitHub

type.inbound
and any(filter(body.current_thread.links,
               regex.icontains(.display_text,
                               '(?:REF|S?RF[PQI]|BID|PROP)(?:-(?:[A-Z][0-9][A-Z][0-9]|[A-Z]{2}[0-9]{2})){2}'
               )
        ),
        .href_url.domain.root_domain != sender.email.domain.root_domain
)
and not (
  sender.email.domain.root_domain in $high_trust_sender_root_domains
  and coalesce(headers.auth_summary.dmarc.pass, false)
)

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