Sync from PR#2235

Update impersonation_sharepoint_body_credential_theft.yml by @aidenmitchell
#2235
Source SHA f7920a4
Triggered by @aidenmitchell

detection-rules/impersonation_sharepoint_body_credential_theft.yml

@@ -0,0 +1,63 @@
+name: "Brand impersonation: Sharepoint"
+description: |
+  Body, attached images or pdf contains a Sharepoint logo. The message contains a link and credential theft language.
+type: "rule"
+severity: "high"
+source: |
+  type.inbound
+  and length(body.links) > 0
+  and (
+    any(attachments,
+        (.file_type in $file_types_images or .file_type == "pdf")
+        and any(ml.logo_detect(.).brands, .name == "Microsoft SharePoint")
+    )
+    or any(ml.logo_detect(beta.message_screenshot()).brands,
+           .name == "Microsoft SharePoint"
+    )
+    or strings.istarts_with(strings.replace_confusables(body.current_thread.text), "Sharepoint")
+    or regex.icontains(body.html.raw, '<img.*(title=|alt=).share.*src=""')  // broken Sharepoint logo
+  )
+  and (
+    (
+      any(ml.nlu_classifier(body.current_thread.text).intents,
+          .name == "cred_theft" and .confidence == "high"
+      )
+      or any(file.explode(beta.message_screenshot()),
+             any(ml.nlu_classifier(.scan.ocr.raw).intents,
+                 .name == "cred_theft" and .confidence == "high"
+             )
+      )
+    )
+    or any(ml.nlu_classifier(body.current_thread.text).entities,
+           .name == "urgency" and strings.ilike(.text, "*encrypted*")
+    )
+  )
+  and (
+    profile.by_sender_email().prevalence != 'common'
+    or not profile.by_sender_email().solicited
+    or profile.by_sender().any_messages_malicious_or_spam
+  )
+  and not profile.by_sender().any_false_positives
+
+  // 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"
+tactics_and_techniques:
+  - "Impersonation: Brand"
+  - "Social engineering"
+detection_methods:
+  - "Computer Vision"
+  - "Content analysis"
+  - "File analysis"
+  - "Natural Language Understanding"
+  - "Sender analysis"
+id: "284b1b70-8daa-5adf-9df8-15d4c6b5ead9"
+testing_pr: 2235
+testing_sha: f7920a4a50e1fd1c893dd9ea0c89126a394037e1