Name:Cloud Compute Instance Created In Previously Unused Region id:fa4089e2-50e3-40f7-8469-d2cc1564ca59 version:3 date:2024-10-17 author:David Dorsey, Splunk status:experimental type:Anomaly Description:The following analytic detects the creation of a cloud compute instance in a region that has not been previously used within the last hour. It leverages cloud infrastructure logs and compares the regions of newly created instances against a lookup file of historically used regions. This activity is significant because the creation of instances in new regions can indicate unauthorized or suspicious activity, such as an attacker attempting to evade detection or establish a foothold in a less monitored area. If confirmed malicious, this could lead to unauthorized resource usage, data exfiltration, or further compromise of the cloud environment. Data_source:
-AWS CloudTrail
search:| tstats earliest(_time) as firstTime latest(_time) as lastTime values(All_Changes.object_id) as dest, count from datamodel=Change where All_Changes.action=created by All_Changes.vendor_region, All_Changes.user | `drop_dm_object_name("All_Changes")` | lookup previously_seen_cloud_regions vendor_region as vendor_region OUTPUTNEW firstTimeSeen, enough_data | eventstats max(enough_data) as enough_data | where enough_data=1 | eval firstTimeSeenRegion=min(firstTimeSeen) | where isnull(firstTimeSeenRegion) OR firstTimeSeenRegion > relative_time(now(), "-24h@h") | table firstTime, user, dest, count , vendor_region | `security_content_ctime(firstTime)` | `cloud_compute_instance_created_in_previously_unused_region_filter`
how_to_implement:You must be ingesting your cloud infrastructure logs from your cloud provider. You should run the baseline search `Previously Seen Cloud Regions - Initial` to build the initial table of images observed and times. You must also enable the second baseline search `Previously Seen Cloud Regions - Update` to keep this table up to date and to age out old data. You can also provide additional filtering for this search by customizing the `cloud_compute_instance_created_in_previously_unused_region_filter` macro. known_false_positives:It's possible that a user has unknowingly started an instance in a new region. Please verify that this activity is legitimate. References: drilldown_searches:
: tags: analytic_story: - 'Cloud Cryptomining' asset_type:Cloud Compute Instance confidence:60 impact:70 message:User $user$ is creating an instance $dest$ in a new region for the first time mitre_attack_id: - 'T1535' observable: name:'user' type:'User' - role: - 'Attacker' name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'All_Changes.object_id' - 'All_Changes.action' - 'All_Changes.vendor_region' - 'All_Changes.user' risk_score:42 security_domain:threat
