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Description

This search looks at S3 bucket-access logs and detects new or previously unseen remote IP addresses that have successfully accessed an S3 bucket.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel:
  • Last Updated: 2018-06-28
  • Author: Bhavin Patel, Splunk
  • ID: 2a9b80d3-6340-4345-b5ad-291bq3d0daq4

ATT&CK

ID Technique Tactic
T1530 Data from Cloud Storage Object Collection
`aws_s3_accesslogs` http_status=200  [search `aws_s3_accesslogs` http_status=200 
| stats earliest(_time) as firstTime latest(_time) as lastTime by bucket_name remote_ip 
| inputlookup append=t previously_seen_S3_access_from_remote_ip.csv 
| stats min(firstTime) as firstTime, max(lastTime) as lastTime by bucket_name remote_ip 
| outputlookup previously_seen_S3_access_from_remote_ip.csv 
| eval newIP=if(firstTime >= relative_time(now(), "-70m@m"), 1, 0) 
| where newIP=1 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| table bucket_name remote_ip]
| iplocation remote_ip 
|rename remote_ip as src_ip 
| table _time bucket_name src_ip City Country operation request_uri 
| `detect_s3_access_from_a_new_ip_filter`

Associated Analytic Story

How To Implement

You must install the AWS App for Splunk (version 5.1.0 or later) and Splunk Add-on for AWS (version 4.4.0 or later), then configure your S3 access logs' inputs. This search works best when you run the "Previously Seen S3 Bucket Access by Remote IP" support search once to create a history of previously seen remote IPs and bucket names.

Required field

  • _time
  • http_status
  • bucket_name
  • remote_ip

Kill Chain Phase

  • Actions on Objectives

Known False Positives

S3 buckets can be accessed from any IP, as long as it can make a successful connection. This will be a false postive, since the search is looking for a new IP within the past hour

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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