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

Techniques

T1530

Sample rules

Detect S3 access from a new IP

source: splunk
technicques:
- T1530

Description

The following analytic identifies access to an S3 bucket from a new or previously unseen remote IP address. It leverages S3 bucket-access logs, specifically focusing on successful access events (http_status=200). This activity is significant because access from unfamiliar IP addresses could indicate unauthorized access or potential data exfiltration attempts. If confirmed malicious, this activity could lead to unauthorized data access, data theft, or further exploitation of the compromised S3 bucket, posing a significant risk to sensitive information stored within the bucket.

Detection logic

`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 
| stats min(firstTime) as firstTime, max(lastTime) as lastTime by bucket_name remote_ip 
| outputlookup previously_seen_S3_access_from_remote_ip
| 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`