diff --git a/detection-rules/link_file_sharing_link_removed.yml b/detection-rules/link_file_sharing_link_removed.yml new file mode 100644 index 00000000000..ba7cadccd98 --- /dev/null +++ b/detection-rules/link_file_sharing_link_removed.yml @@ -0,0 +1,34 @@ +name: "Link: File sharing link removed by provider" +description: "This rule detects messages to file sharing hosts where the file or link has been removed by the provider. " +type: "rule" +severity: "medium" +source: | + type.inbound + // No Recipients + and ( + length(recipients.to) == 0 + or all(recipients.to, .display_name == "Undisclosed recipients") + ) + and length(recipients.cc) == 0 + and length(recipients.bcc) == 0 + + and ( + any(body.links, + any(file.explode(beta.linkanalysis(.).screenshot), + any([ + "This shared file or folder link has been removed or is unavailable", + "This transfer has been deleted and is not available anymore", + "This item might not exist or is no longer available", + "the file you have requested does not exist", + "This file isn’t here anymore" + ], strings.icontains(..scan.ocr.raw, .)) + ) + ) + ) + +detection_methods: + - "Header analysis" + - "Optical Character Recognition" + - "URL analysis" + - "URL screenshot" +id: "fc6e11e0-7db6-5366-9a9f-a107452da0f1"