This search looks for AWS provisioning activities from previously unseen IP addresses. Provisioning activities are defined broadly as any event that begins with “Run” or “Create.” This search is deprecated and have been translated to use the latest Change Datamodel.
- Type: Anomaly
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2018-03-16
- Author: David Dorsey, Splunk
- ID: 42e15012-ac14-4801-94f4-f1acbe64880b
Kill Chain Phase
- CIS 1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 `cloudtrail` (eventName=Run* OR eventName=Create*) [search `cloudtrail` (eventName=Run* OR eventName=Create*) | iplocation sourceIPAddress | search Country=* | stats earliest(_time) as firstTime, latest(_time) as lastTime by sourceIPAddress, City, Region, Country | inputlookup append=t previously_seen_provisioning_activity_src.csv | stats min(firstTime) as firstTime max(lastTime) as lastTime by sourceIPAddress, City, Region, Country | outputlookup previously_seen_provisioning_activity_src.csv | stats min(firstTime) as firstTime max(lastTime) as lastTime by sourceIPAddress | eval newIP=if(firstTime >= relative_time(now(), "-70m@m"), 1, 0) | where newIP=1 | table sourceIPAddress] | spath output=user userIdentity.arn | rename sourceIPAddress as src_ip | table _time, user, src_ip, eventName, errorCode | `aws_cloud_provisioning_from_previously_unseen_ip_address_filter`
The SPL above uses the following Macros:
aws_cloud_provisioning_from_previously_unseen_ip_address_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
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 AWS CloudTrail inputs. This search works best when you run the “Previously Seen AWS Provisioning Activity Sources” support search once to create a history of previously seen locations that have provisioned AWS resources.
Known False Positives
This is a strictly behavioral search, so we define “false positive” slightly differently. Every time this fires, it will accurately reflect the first occurrence in the time period you’re searching within, plus what is stored in the cache feature. But while there are really no “false positives” in a traditional sense, there is definitely lots of noise.
This search will fire any time a new IP address is seen in the GeoIP database for any kind of provisioning activity. If you typically do all provisioning from tools inside of your country, there should be few false positives. If you are located in countries where the free version of MaxMind GeoIP that ships by default with Splunk has weak resolution (particularly small countries in less economically powerful regions), this may be much less valuable to you.
Associated Analytic story
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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