Sync from PR#2079

Create brand_impersonation_knowbe4.yml by @zoomequipd
#2079
Source SHA 03b6b2d
Triggered by @zoomequipd

detection-rules/brand_impersonation_knowbe4.yml

@@ -0,0 +1,42 @@
+name: "Brand impersonation: KnowBe4"
+description: "Impersonation of KnowBe4."
+type: "rule"
+severity: "medium"
+source: |
+  type.inbound
+  and (
+    sender.display_name =~ 'KnowBe4'
+    or strings.ilevenshtein(sender.display_name, 'KnowBe4') <= 1
+    or strings.icontains(sender.email.domain.domain, '*KnowBe4*')
+  )
+  and (
+    sender.email.domain.root_domain not in ('knowbe4.com')
+    or (
+      sender.email.domain.root_domain in ('knowbe4.com')
+      and not headers.auth_summary.dmarc.pass
+    )
+  )
+
+  // 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
+  )
+attack_types:
+  - "Credential Phishing"
+  - "Spam"
+tactics_and_techniques:
+  - "Free email provider"
+  - "Impersonation: Brand"
+  - "Lookalike domain"
+  - "Social engineering"
+detection_methods:
+  - "Computer Vision"
+  - "Header analysis"
+  - "Sender analysis"
+id: "7c798386-fd25-5890-83b3-85187adbfc44"
+testing_pr: 2079
+testing_sha: 03b6b2dd2a625f43dcfef39833acba7d1934437c