Techniques
Sample rules
Cloud Instance Modified By Previously Unseen User
- source: splunk
- technicques:
- T1078.004
Description
The following analytic identifies cloud instances being modified by users who have not previously modified them. It leverages data from the Change data model, focusing on successful modifications of EC2 instances. This activity is significant because it can indicate unauthorized or suspicious changes by potentially compromised or malicious users. If confirmed malicious, this could lead to unauthorized access, configuration changes, or potential disruption of cloud services, posing a significant risk to the organization’s cloud infrastructure.
Detection logic
| tstats `security_content_summariesonly` count earliest(_time) as firstTime, latest(_time) as lastTime values(All_Changes.object_id) as object_id values(All_Changes.command) as command from datamodel=Change where All_Changes.action=modified All_Changes.change_type=EC2 All_Changes.status=success by All_Changes.user
| `drop_dm_object_name("All_Changes")`
| lookup previously_seen_cloud_instance_modifications_by_user user as user OUTPUTNEW firstTimeSeen, enough_data
| eventstats max(enough_data) as enough_data
| where enough_data=1
| eval firstTimeSeenUser=min(firstTimeSeen)
| where isnull(firstTimeSeenUser) OR firstTimeSeenUser > relative_time(now(), "-24h@h")
| table firstTime user command object_id count
| `security_content_ctime(firstTime)`
| `cloud_instance_modified_by_previously_unseen_user_filter`