• Sublime Core Feed

Description

This rule detects Google Drive links that use the direct download URL pattern which automatically downloads files when clicked. This pattern is frequently used by threat actors to distribute malware.

The links are formatted like: drive.google.com/uc?id=FILE_ID&export=download

These links skip the preview page and immediately download the file to the user's device, which can be dangerous for recipients. Threat actors exploit this pattern to directly distribute malware while appearing to share legitimate content from a trusted service.

References

No references.

Sublime Security
Created Mar 5th, 2025 • Last updated Jul 16th, 2025
Source
type.inbound
and 0 < length(body.links) < 10
and any(body.links,
        (
          // Match Google Drive direct download links
          strings.icontains(.href_url.url, "drive.google.com/uc") 
          and (
            strings.icontains(.href_url.url, "export=download")
            or strings.icontains(.href_url.query_params, "export=download")
          )
        )
)
// negate highly trusted sender domains unless they fail DMARC authentication
and (
  (
    sender.email.domain.root_domain in $high_trust_sender_root_domains
    and not headers.auth_summary.dmarc.pass
  )
  or sender.email.domain.root_domain not in $high_trust_sender_root_domains
)
and (
  // Only trigger on unsolicited senders
  not profile.by_sender().solicited
  or (
    // Or senders with suspicious history
    profile.by_sender().any_messages_malicious_or_spam
    and not profile.by_sender().any_messages_benign
  )
)
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