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Bhavin Patel
66 lines
2.4 KiB
YAML
66 lines
2.4 KiB
YAML
name: AWS Lambda UpdateFunctionCode
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id: 211b80d3-6340-4345-11ad-212bf3d0d111
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version: 2
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date: '2024-05-13'
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author: Bhavin Patel, Splunk
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status: production
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type: Hunting
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description: The following analytic identifies IAM users attempting to update or modify
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AWS Lambda code via the AWS CLI. It leverages CloudTrail logs to detect successful
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`UpdateFunctionCode` events initiated by IAM users. This activity is significant
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as it may indicate an attempt to gain persistence, further access, or plant backdoors
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within your AWS environment. If confirmed malicious, an attacker could upload and
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execute malicious code automatically when the Lambda function is triggered, potentially
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compromising the integrity and security of your AWS infrastructure.
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data_source:
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- AWS CloudTrail
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search: '`cloudtrail` eventSource=lambda.amazonaws.com eventName=UpdateFunctionCode* errorCode
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= success user_type=IAMUser | stats count min(_time) as firstTime max(_time) as
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lastTime values(requestParameters.functionName) as function_updated by src_ip user_arn
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user_agent user_type eventName aws_account_id |`aws_lambda_updatefunctioncode_filter`'
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how_to_implement: You must install Splunk AWS Add on and enable Cloudtrail logs in
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your AWS Environment.
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known_false_positives: While this search has no known false positives, it is possible
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that an AWS admin or an autorized IAM user has updated the lambda fuction code legitimately.
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references:
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- http://detectioninthe.cloud/execution/modify_lambda_function_code/
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- https://sysdig.com/blog/exploit-mitigate-aws-lambdas-mitre/
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tags:
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analytic_story:
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- Suspicious Cloud User Activities
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asset_type: AWS Account
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confidence: 90
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impact: 70
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message: User $user_arn$ is attempting to update the lambda function code of $function_updated$
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from this IP $src_ip$
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mitre_attack_id:
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- T1204
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observable:
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- name: src_ip
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type: IP Address
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role:
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- Attacker
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- name: user_arn
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type: User
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role:
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- Attacker
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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required_fields:
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- _time
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- eventName
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- userAgent
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- errorCode
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risk_score: 63
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security_domain: cloud
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tests:
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- name: True Positive Test
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attack_data:
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- data:
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https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1204/aws_updatelambdafunctioncode/aws_cloudtrail_events.json
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sourcetype: aws:cloudtrail
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source: aws_cloudtrail
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update_timestamp: true
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