THIS IS A EXPERIMENTAL DETECTION
This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.
This analytic looks for several delete specific API calls made to AWS Security Services like CloudWatch, GuardDuty and Web Application Firewalls. These API calls are often leveraged by adversaries to weaken existing security defenses by deleting logging configurations in the CloudWatch alarm, delete a set of detectors from your Guardduty environment or simply delete a bunch of CloudWatch alarms to remain stealthy and avoid detection.
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Web
- Last Updated: 2023-06-01
- Author: Patrick Bareiss, Bhavin Patel, Gowthamaraj Rajendran, Splunk
- ID: 5029b681-0462-47b7-82e7-f7e3d37f5a2d
Kill Chain Phase
- CIS 10
1 2 3 4 5 `amazon_security_lake` api.operation IN ("DeleteLogStream","DeleteDetector","DeleteIPSet","DeleteWebACL","DeleteRule","DeleteRuleGroup","DeleteLoggingConfiguration","DeleteAlarms") | stats count min(_time) as firstTime max(_time) as lastTime by api.operation identity.user.account_uid identity.user.credential_uid identity.user.name identity.user.type identity.user.uid identity.user.uuid http_request.user_agent src_endpoint.ip cloud.region | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `asl_aws_defense_evasion_impair_security_services_filter`
The SPL above uses the following Macros:
asl_aws_defense_evasion_impair_security_services_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
You must install Splunk Add-On for AWS Version v7.0.0 (https://splunkbase.splunk.com/app/1876) that includes includes a merge of all the capabilities of the Splunk Add-on for Amazon Security Lake. This search works with Amazon Security Lake logs which are parsed in the Open Cybersecurity Schema Framework (OCSF)format.
Known False Positives
While this search has no known false positives, it is possible that it is a legitimate admin activity. Please consider filtering out these noisy events using userAgent, user_arn field names.
Associated Analytic Story
|42.0||70||60||User $identity.user.name$ has made potentially risky api calls $api.operation$ that could impair AWS security services for account id $identity.user.account_uid$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1