sublimehighRule

Brand impersonation: Deloitte LLC domain in CC

Flags inbound messages where a recipient in the CC field—either in the message itself or within a previous email thread included in the body—uses the deloittellc.com root domain. This can indicate an attempt to impersonate or leverage Deloitte's identity to add legitimacy to a message or exploit a hijacked thread.

MITRE ATT&CK

T1566.002 T1534 T1656 T1598.003 T1566 T1598

initial-access

Detection Query

type.inbound
and (
  any(recipients.cc, .email.domain.root_domain == 'deloittellc.com')
  or any(body.previous_threads,
         any(.recipients.cc, .email.domain.root_domain == 'deloittellc.com')
  )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Brand impersonation: Deloitte LLC domain in CC"
description: "Flags inbound messages where a recipient in the CC field—either in the message itself or within a previous email thread included in the body—uses the deloittellc.com root domain. This can indicate an attempt to impersonate or leverage Deloitte's identity to add legitimacy to a message or exploit a hijacked thread."
type: "rule"
severity: "high"
source: |
  type.inbound
  and (
    any(recipients.cc, .email.domain.root_domain == 'deloittellc.com')
    or any(body.previous_threads,
           any(.recipients.cc, .email.domain.root_domain == 'deloittellc.com')
    )
  )
attack_types:
  - "BEC/Fraud"
tactics_and_techniques:
  - "Impersonation: Brand"
  - "Social engineering"
detection_methods:
  - "Header analysis"
id: "372f5c7f-eb89-56c7-897b-1ec30bfb26d3"