Description

This rule detects PDF files containing a DocuSign logo linking to a newly created domain (Less than or equal to 3 days)

References

No references.

Sublime Security
Created Oct 26th, 2023 • Last updated Sep 23rd, 2026
Source
type.inbound
and any(attachments,
        .file_type == "pdf"
        and any(ml.logo_detect(.).brands, .name == "DocuSign")
        and any(file.explode(.),
                any(.scan.pdf.urls, network.whois(.domain).days_old <= 3)
        )
)

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

// excludes senders that contain "via" in the display name a resilient way
and not (
  any(headers.hops,
      any(.fields,
          .name == "X-Api-Host" and strings.ends_with(.value, "docusign.net")
      )
  )
)
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