VIP / Executive impersonation (untrusted)

Sender display name matches the display name of a user in the $org_vips list, and the sender has never been seen before.

The $org_vips list must first be manually connected to a VIP group of your upstream provider (Google Workspace and Microsoft 365 only) in order for this rule to work. Once connected, the list will be automatically synced and kept up-to-date. For more information, see the $org_vips documentation: https://docs.sublimesecurity.com/docs/configure-org_vips-list

This rule is recommended to be used on a relatively small list of VIPs, and is meant to reduce attack surface by detecting any message that matches the protected list of display names from a first-time or unsolicited sender.

Additional rule logic can be added to look for suspicious subjects, suspicious links, etc.

Sublime rule (View on GitHub)

 1name: "VIP / Executive impersonation (untrusted)"
 2description: |
 3  Sender display name matches the display name of a user in the $org_vips list, and the sender has never been seen before.
 4
 5  The $org_vips list must first be manually connected to a VIP group of your upstream provider (Google Workspace and Microsoft 365 only) in order for this rule to work.
 6  Once connected, the list will be automatically synced and kept up-to-date. For more information, see the $org_vips documentation: https://docs.sublimesecurity.com/docs/configure-org_vips-list
 7
 8  This rule is recommended to be used on a relatively small list of VIPs, and is meant to reduce attack surface by detecting *any* message that matches the protected list of display names from a first-time or unsolicited sender.
 9
10  Additional rule logic can be added to look for suspicious subjects, suspicious links, etc.  
11type: "rule"
12severity: "high"
13source: |
14  type.inbound
15  and any($org_vips, .display_name =~ sender.display_name)
16  and (
17    // ignore personal <> work emails
18    // where the sender and mailbox's display name are the same
19    length(recipients.to) > 1
20    or length(recipients.cc) > 1
21    or sender.display_name != mailbox.display_name
22  )
23  and (
24    (
25      profile.by_sender().prevalence in ("new", "outlier")
26      and not profile.by_sender().solicited
27    )
28    or (
29      profile.by_sender().any_messages_malicious_or_spam
30      and not profile.by_sender().any_false_positives
31    )
32  )
33  and (
34    (
35      sender.email.domain.root_domain in $org_domains
36      and (
37        any(distinct(headers.hops, .authentication_results.dmarc is not null),
38            strings.ilike(.authentication_results.dmarc, "*fail")
39        )
40      )
41    )
42    or sender.email.domain.root_domain not in $org_domains
43  )
44  and not profile.by_sender().any_false_positives  
45attack_types:
46  - "BEC/Fraud"
47tactics_and_techniques:
48  - "Impersonation: VIP"
49detection_methods:
50  - "Header analysis"
51  - "Sender analysis"
52id: "e42c84b7-9d50-5870-9a5d-311670a14bc1"
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