Medium Severity

Link: Credential theft via newly registered suspicious domain in query parameter

Description

Detects inbound messages where NLU classification identifies credential theft intent in the message body, and a link contains a query parameter that decodes to a URL with a suspicious top-level domain registered within the last 30 days. Excludes messages from high-trust sender domains that pass DMARC authentication.

References

No references.

Sublime Security
Created Oct 9th, 2026 • Last updated Oct 9th, 2026
Source
type.inbound
and any(ml.nlu_classifier(body.current_thread.text).intents,
        .name == 'cred_theft' and .confidence != 'low'
)
and any(filter(body.current_thread.links, .href_url.scheme != 'mailto'),
        any(flatten(values(.href_url.query_params_decoded)),
            strings.parse_url(.).domain.valid
            and strings.parse_url(.).domain.tld in $suspicious_tlds
            and network.whois(strings.parse_url(.).domain).days_old < 30
        )
)
and not (
  (
    sender.email.domain.root_domain in $high_trust_sender_root_domains
    or sender.email.domain.root_domain in ("supabase.io")
  )
  and coalesce(headers.auth_summary.dmarc.pass, false)
)
MQL Rule Console
•Docs•Learning Labs

Playground

Test against your own EMLs or sample data.

Share

Post about this on your socials.

Get Started. Today.

Managed or self-managed. No MX changes.

Deploy and integrate a free Sublime instance in minutes.
Get Started