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splunk-security_content/detections/cloud/aws_lambda_updatefunctioncode.yml
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2022-02-28 11:28:27 -08:00

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YAML

name: AWS Lambda UpdateFunctionCode
id: 211b80d3-6340-4345-11ad-212bf3d0d111
version: 1
date: '2022-02-24'
author: Bhavin Patel, Splunk
type: Hunting
datamodel: []
description: This analytic is designed to detect IAM users attempting to update/modify AWS lambda code via the AWS CLI to gain persistence, futher access into your AWS environment and to facilitate planting backdoors.
search: '`cloudtrail` eventSource=lambda.amazonaws.com eventName=UpdateFunctionCode* errorCode = success user_type=IAMUser | stats count min(_time) as firstTime max(_time) as lastTime values(requestParameters.functionName) as function_updated by src_ip user_arn user_agent user_type eventName aws_account_id |`aws_lambda_updatefunctioncode_filter`'
how_to_implement: You must install Splunk AWS add on and Splunk App for AWS. This
search works with AWS CloudTrail logs.
known_false_positives: While this search has no known false positives, it is possible
that an AWS admin or an autorized IAM user has updated the lambda code legitimately.
references:
- http://detectioninthe.cloud/execution/modify_lambda_function_code/
- https://sysdig.com/blog/exploit-mitigate-aws-lambdas-mitre/
tags:
analytic_story:
- Suspicious Cloud User Activities
asset_type: AWS Account
automated_detection_testing: passed
cis20:
- CIS 13
confidence: 90
context:
- Source:Cloud Data
- Scope:External
- Outcome:Allowed
- Stage:Execution
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1204/aws_updatelambdafunctioncode/aws_cloudtrail_events.json
impact: 70
kill_chain_phases:
- Actions on Objectives
message: User $user_arn$ is attempting to create access keys for $requestParameters.userName$
from this IP $src$
mitre_attack_id:
- T1204
nist:
- PR.DS
- PR.AC
- DE.CM
observable:
- name: src_ip
type: IP Address
role:
- Attacker
- name: user_arn
type: User
role:
- Attacker
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- eventName
- userAgent
- errorCode
risk_score: 63
security_domain: cloud