diff --git a/detection-rules/link_limewire_direct.yml b/detection-rules/link_limewire_direct.yml new file mode 100644 index 00000000000..bb02a82e20e --- /dev/null +++ b/detection-rules/link_limewire_direct.yml @@ -0,0 +1,36 @@ +name: "Link: Direct link to limewire hosted file" +description: "Message contains exactly one link to limewire.com domain with fewer than 10 total links in the body." +type: "rule" +severity: "high" +source: | + type.inbound + // there are few links + and length(body.links) < 10 + // contains a link to limewire + and any(body.links, .href_url.domain.domain == "limewire.com") + // is the only link to limewire + and length(filter(body.links, + .href_url.domain.root_domain == "limewire.com" + and strings.istarts_with(.href_url.path, "/d/") + ) + ) == 1 + and not length(body.previous_threads) > 0 + // 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 + ) + and not profile.by_sender_email().any_messages_benign +tags: + - "Attack surface reduction" +attack_types: + - "Malware/Ransomware" +tactics_and_techniques: + - "Free file host" +detection_methods: + - "URL analysis" + - "Content analysis" +id: "70840d00-c6e3-59ec-8dc5-8156e61abec6"