diff --git a/detection-rules/headers_tld_in_hops_with_authfailure_or_credtheft.yml b/detection-rules/headers_tld_in_hops_with_authfailure_or_credtheft.yml new file mode 100644 index 00000000000..78351fb932a --- /dev/null +++ b/detection-rules/headers_tld_in_hops_with_authfailure_or_credtheft.yml @@ -0,0 +1,29 @@ +name: "Suspicious TLD in headers with SPF/DMARC failures or high confidence credential theft" +description: | + Flags inbound emails with suspicious TLDs in the headers, SPF/DMARC failures, or high-confidence credential theft indicators +type: "rule" +severity: "medium" +source: | + type.inbound + and any(headers.domains, .tld in $suspicious_tlds and .tld != sender.email.domain.tld) + // SPF Errors/Failures or DMARC Fail + and ( + any(distinct(headers.hops, .received_spf.verdict is not null), + regex.icontains(.received_spf.verdict, "fail|error") + or any(distinct(headers.hops, .authentication_results.dmarc is not null), + strings.ilike(.authentication_results.dmarc, "*fail") + + // Or Cred_theft confidence High + or any(ml.nlu_classifier(body.current_thread.text).intents, + .name in ("cred_theft") and .confidence == "high" + ) + ) + ) + ) +attack_types: + - "BEC/Fraud" + - "Credential Phishing" +detection_methods: + - "Header analysis" + - "Natural Language Understanding" +id: "e8696023-4a1e-542a-8c22-784a3d33c7a4"