AWSCloudTrail - Successful brute force attack on S3 Bucket

Requête originale, sans modification.

let timeframe = 1h;
let failed_attempts = AWSCloudTrail
| where TimeGenerated >= ago(timeframe)
| where EventName == "GetObject" and isnotempty(ErrorMessage) and isnotempty(ErrorCode)
| where UserIdentityAccountId == "ANONYMOUS_PRINCIPAL" or UserIdentityAccessKeyId <> RecipientAccountId
| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
| extend UserName = tostring(split(UserIdentityArn, '/')[-1])
| extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
| extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
  AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)
| summarize time_min_failed=arg_min(TimeGenerated, *), failed_keys = dcount(keyName) by RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, SourceIpAddress, bucketName
| where failed_keys > 20;
let success_attempts = AWSCloudTrail
| where TimeGenerated >= ago(timeframe)
| where EventName == "GetObject" and isempty(ErrorMessage) and isempty(ErrorCode)
| where UserIdentityAccountId == "ANONYMOUS_PRINCIPAL" or UserIdentityAccessKeyId <> RecipientAccountId
| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
| extend UserName = tostring(split(UserIdentityArn, '/')[-1])
| extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
| extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
  AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)
| summarize time_min_success=arg_min(TimeGenerated, *), success_keys = dcount(keyName) by RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, SourceIpAddress, bucketName
| where success_keys >= 1;
failed_attempts
| join kind=inner success_attempts on SourceIpAddress, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, bucketName
| where time_min_success > time_min_failed
| project-away keyName