Linked Malicious Storage Artifacts

Requête originale, sans modification.

//Collect the alert events
let alertData = SecurityAlert
| where DisplayName has "Potential malware uploaded to"
| extend Entities = parse_json(Entities)
| mv-expand Entities;
//Parse the IP address data
let ipData = alertData
| where Entities['Type'] =~ "ip"
| extend AttackerIP = tostring(Entities['Address']), AttackerCountry = tostring(Entities['Location']['CountryName']);
//Parse the file data
let FileData = alertData
| where Entities['Type'] =~ "file"
| extend MaliciousFileDirectory = tostring(Entities['Directory']), MaliciousFileName = tostring(Entities['Name']), MaliciousFileHashes = tostring(Entities['FileHashes']);
//Combine the File and IP data together
ipData
| join (FileData) on VendorOriginalId
| summarize by TimeGenerated, AttackerIP, AttackerCountry, DisplayName, ResourceId, AlertType, MaliciousFileDirectory, MaliciousFileName, MaliciousFileHashes
//Create a type column so we can track if it was a File storage or blobl storage upload
| extend type = iff(DisplayName has "file", "File", "Blob")
| join (
  union
  StorageFileLogs,
  StorageBlobLogs
  //File upload operations
  | where OperationName =~ "PutBlob" or OperationName =~ "PutRange"
  //Parse out the uploader IP
  | extend ClientIP = tostring(split(CallerIpAddress, ":", 0)[0])
  //Extract the filename from the Uri
  | extend FileName = extract(@"\/([\w\-. ]+)\?", 1, Uri)
  //Base64 decode the MD5 filehash, we will encounter non-ascii hex so string operations don't work
  //We can work around this by making it an array then converting it to hex from an int
  | extend base64Char = base64_decode_toarray(ResponseMd5)
  | mv-expand base64Char
  | extend hexChar = tohex(toint(base64Char))
  | extend hexChar = iff(strlen(hexChar) < 2, strcat("0", hexChar), hexChar)
  | extend SourceTable = iff(OperationName has "range", "StorageFileLogs", "StorageBlobLogs")
  | summarize make_list(hexChar, 1000) by CorrelationId, ResponseMd5, FileName, AccountName, TimeGenerated, RequestBodySize, ClientIP, SourceTable
  | extend Md5Hash = strcat_array(list_hexChar, "")
  //Pack the file information the summarise into a ClientIP row
  | extend p = pack("FileName", FileName, "FileSize", RequestBodySize, "Md5Hash", Md5Hash, "Time", TimeGenerated, "SourceTable", SourceTable)
  | summarize UploadedFileInfo=make_list(p, 10000), FilesUploaded=count() by ClientIP
      | join kind=leftouter (
        union
        StorageFileLogs,
        StorageBlobLogs
        | where OperationName =~ "DeleteFile" or OperationName =~ "DeleteBlob"
        | extend ClientIP = tostring(split(CallerIpAddress, ":", 0)[0])
        | extend FileName = extract(@"\/([\w\-. ]+)\?", 1, Uri)
        | extend SourceTable = iff(OperationName has "range", "StorageFileLogs", "StorageBlobLogs")
        | extend p = pack("FileName", FileName, "Time", TimeGenerated, "SourceTable", SourceTable)
        | summarize DeletedFileInfo=make_list(p, 10000), FilesDeleted=count() by ClientIP
        ) on ClientIP
  ) on $left.AttackerIP == $right.ClientIP
| mvexpand UploadedFileInfo
| extend LinkedMaliciousFileName = tostring(UploadedFileInfo.FileName)
| extend LinkedMaliciousFileHash = tostring(UploadedFileInfo.Md5Hash)
| extend HashAlgorithm = "MD5"
| project AlertTimeGenerated = TimeGenerated, LinkedMaliciousFileName, LinkedMaliciousFileHash, HashAlgorithm, AlertType, AttackerIP, AttackerCountry, MaliciousFileDirectory, MaliciousFileName, FilesUploaded, UploadedFileInfo