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Description

The following analytic detects failed attempts to delete AWS IAM groups, triggered by access denial, conflicts, or non-existent groups. It operates by monitoring CloudTrail logs for specific error codes related to deletion failures. This behavior is significant for a SOC as it may indicate unauthorized attempts to modify access controls or disrupt operations by removing groups. Such actions could be part of a larger attack aiming to escalate privileges or impair security protocols. Identifying these attempts allows for timely investigation and mitigation, preventing potential impact on the organizations security posture.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-02-14
  • Author: Patrick Bareiss, Splunk
  • ID: 8d12f268-c567-4557-9813-f8389e235c06

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1098 Account Manipulation Persistence, Privilege Escalation
Kill Chain Phase
  • Installation
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`amazon_security_lake` api.operation=DeleteGroup api.response.error IN (NoSuchEntityException,DeleteConflictException, AccessDenied) http_request.user_agent!=*.amazonaws.com 
| fillnull 
| stats count min(_time) as firstTime max(_time) as lastTime by api.operation actor.user.account_uid actor.user.name actor.user.uid http_request.user_agent src_endpoint.ip cloud.region 
| rename actor.user.name as user, src_endpoint.ip as src_ip, cloud.region as region, http_request.user_agent as user_agent, actor.user.account_uid as aws_account_id 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `asl_aws_iam_failure_group_deletion_filter`

Macros

The SPL above uses the following Macros:

:information_source: asl_aws_iam_failure_group_deletion_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • api.operation
  • actor.user.account_uid
  • actor.user.name
  • actor.user.uid
  • http_request.user_agent
  • src_endpoint.ip
  • cloud.region

How To Implement

The detection is based on Amazon Security Lake events from Amazon Web Services (AWS), which is a centralized data lake that provides security-related data from AWS services. To use this detection, you must ingest CloudTrail logs from Amazon Security Lake into Splunk. To run this search, ensure that you ingest events using the latest version of Splunk Add-on for Amazon Web Services (https://splunkbase.splunk.com/app/1876) or the Federated Analytics App.

Known False Positives

This detection will require tuning to provide high fidelity detection capabilties. Tune based on src addresses (corporate offices, VPN terminations) or by groups of users. Not every user with AWS access should have permission to delete groups (least privilege).

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
5.0 10 50 User $user$ has had mulitple failures while attempting to delete groups from $src_ip$

:information_source: 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: 3