AWS EC2 Startup Shell Script Change

 1title: AWS EC2 Startup Shell Script Change
 2id: 1ab3c5ed-5baf-417b-bb6b-78ca33f6c3df
 3status: test
 4description: Detects changes to the EC2 instance startup script. The shell script will be executed as root/SYSTEM every time the specific instances are booted up.
 5references:
 6    - https://github.com/RhinoSecurityLabs/pacu/blob/866376cd711666c775bbfcde0524c817f2c5b181/pacu/modules/ec2__startup_shell_script/main.py#L9
 7author: faloker
 8date: 2020-02-12
 9modified: 2022-06-07
10tags:
11    - attack.execution
12    - attack.t1059.001
13    - attack.t1059.003
14    - attack.t1059.004
15logsource:
16    product: aws
17    service: cloudtrail
18detection:
19    selection_source:
20        eventSource: ec2.amazonaws.com
21        requestParameters.attribute: 'userData'
22        eventName: ModifyInstanceAttribute
23    condition: selection_source
24falsepositives:
25    - Valid changes to the startup script
26level: high