sublimemediumRule

Google services using g.co shortlinks

Identifies messages from authenticated Google domains containing g.co shortened URLs with a subdomain in either the message body links or thread text.

MITRE ATT&CK

T1566 T1566.001 T1566.002 T1598 T1036 T1027

defense-evasion

Detection Query

type.inbound
// allow for multiple google TLDs
and sender.email.domain.sld == "google"
and headers.auth_summary.spf.pass
// g.co url shortner in links or the current thread to identify the workspace name
and (
  any(body.links,
      .href_url.domain.root_domain == 'g.co'
      and .href_url.domain.subdomain is not null
  )
  or (
    strings.icontains(body.current_thread.text, '.g.co')
    and regex.icontains(body.current_thread.text, '[^\s]+\.g\.co\b')
  )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

References

https://gist.github.com/zachlatta/f86317493654b550c689dc6509973aa4

Raw Content

name: "Google services using g.co shortlinks"
description: "Identifies messages from authenticated Google domains containing g.co shortened URLs with a subdomain in either the message body links or thread text."
references: 
  - "https://gist.github.com/zachlatta/f86317493654b550c689dc6509973aa4"
type: "rule"
severity: "medium"
source: |
  type.inbound
  // allow for multiple google TLDs
  and sender.email.domain.sld == "google"
  and headers.auth_summary.spf.pass
  // g.co url shortner in links or the current thread to identify the workspace name
  and (
    any(body.links,
        .href_url.domain.root_domain == 'g.co'
        and .href_url.domain.subdomain is not null
    )
    or (
      strings.icontains(body.current_thread.text, '.g.co')
      and regex.icontains(body.current_thread.text, '[^\s]+\.g\.co\b')
    )
  )
attack_types:
  - "Credential Phishing"
tactics_and_techniques:
  - "Evasion"
  - "Free email provider"
detection_methods:
  - "Content analysis"
  - "Header analysis"
  - "Sender analysis"
  - "URL analysis"
id: "09ff8a73-c36e-5c2a-822e-3c039ed818f8"