Detect AWS Console Login by User from New City
Description
This search looks for AWS CloudTrail events wherein a console login event by a user was recorded within the last hour, then compares the event to a lookup file of previously seen users (by ARN values) who have logged into the console. The alert is fired if the user has logged into the console for the first time within the last hour
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Authentication
- Last Updated: 2022-08-25
- Author: Bhavin Patel, Eric McGinnis Splunk
- ID: 121b0b11-f8ac-4ed6-a132-3800ca4fc07a
Annotations
ATT&CK
Kill Chain Phase
- Weaponization
- Exploitation
NIST
- DE.AE
CIS20
- CIS 10
CVE
Search
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| tstats earliest(_time) as firstTime latest(_time) as lastTime from datamodel=Authentication where Authentication.signature=ConsoleLogin by Authentication.user Authentication.src
| iplocation Authentication.src
| `drop_dm_object_name(Authentication)`
| rename City as justSeenCity
| table firstTime lastTime user justSeenCity
| join user type=outer [
| inputlookup previously_seen_users_console_logins
| rename City as previouslySeenCity
| stats min(firstTime) AS earliestseen by user previouslySeenCity
| fields earliestseen user previouslySeenCity]
| eval userCity=if(firstTime >= relative_time(now(), "-24h@h"), "New City","Previously Seen City")
| where userCity = "New City"
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| table firstTime lastTime user previouslySeenCity justSeenCity userCity
| `detect_aws_console_login_by_user_from_new_city_filter`
Macros
The SPL above uses the following Macros:
detect_aws_console_login_by_user_from_new_city_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Lookups
The SPL above uses the following Lookups:
Required fields
List of fields required to use this analytic.
- _time
- Authentication.signature
- Authentication.user
- Authentication.src
How To Implement
You must install and configure the Splunk Add-on for AWS (version 5.1.0 or later) and Enterprise Security 6.2, which contains the required updates to the Authentication data model for cloud use cases. Run the Previously Seen Users in AWS CloudTrail - Initial
support search only once to create a baseline of previously seen IAM users within the last 30 days. Run Previously Seen Users in AWS CloudTrail - Update
hourly (or more frequently depending on how often you run the detection searches) to refresh the baselines. You can also provide additional filtering for this search by customizing the detect_aws_console_login_by_user_from_new_city_filter
macro.
Known False Positives
When a legitimate new user logins for the first time, this activity will be detected. Check how old the account is and verify that the user activity is legitimate.
Associated Analytic Story
- Suspicious AWS Login Activities
- Suspicious Cloud Authentication Activities
- AWS Identity and Access Management Account Takeover
- Compromised User Account
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
18.0 | 30 | 60 | User $user$ is logging into the AWS console from City $City$ for the first time |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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
source | version: 2