Unrestricted access between network segments - RDS
Description
Some RDS Cluster or Instances are not defined inside a Database Subnet Group.
Impact
Access to RDS services in a insecure way from the Internet.
Recommendation
Ensure that all RDS instances belong to a Database Subnet Group.
Threat
Authenticated attacker from the Internet.
Expected Remediation Time
⌚ 90 minutes.
Score
Default score using CVSS 3.1. It may change depending on the context of the vulnerability.
Base
- Attack vector: N
- Attack complexity: L
- Privileges required: H
- User interaction: N
- Scope: U
- Confidentiality: L
- Integrity: L
- Availability: L
Temporal
- Exploit code madurity: P
- Remediation level: O
- Report confidence: C
Result
- Vector string: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
- Score:
- Base: 4.7
- Temporal: 4.2
- Severity:
- Base: Medium
- Temporal: Medium
Code Examples
Compliant code
The resources have defined security groups
Resources:
MyLaunchTemplate:
Type: AWS::EC2::LaunchTemplate
Properties:
LaunchTemplateName: MyLaunchTemplate
LaunchTemplateData:
InstanceType: t2.micro
KeyName: MyKeyPair
SecurityGroupIds:
- sg-083cd3bfb8example
MyEC2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: "ami-79fd7eee"
KeyName: "testkey"
SecurityGroups:
- name1
Non compliant code
There are some resources which use the pre defined security group or do not define one
Resources:
MyLaunchTemplate:
Type: AWS::EC2::LaunchTemplate
Properties:
LaunchTemplateName: MyLaunchTemplate
LaunchTemplateData:
InstanceType: t2.micro
KeyName: MyKeyPair
MyEC2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: "ami-79fd7eee"
KeyName: "testkey"
Using the AWS CLI, the following command checks the subnet groups associated with a given database instance subnet ID
$ aws ec2 describe-route-tables
--region us-east-1
--filters "Name=association.subnet-id,Values=subnet-19e7cc6f"
--query 'RouteTables[*].Routes[]'
If the output contains any entries with the GatewayId value set to igw-xxxxxxxx and the DestinationCidrBlock value set to 0.0.0.0/0, the selected RDS database instance was provisioned inside a public subnet, and has an insecure configuration
Requirements
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