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Nuclei Templates

Restrict EC2 Telnet Access

ID: ec2-unrestricted-telnet

Severity: critical

Author: princechaddha

Tags: cloud,devops,aws,amazon,ec2,aws-cloud-config

Description

Section titled “Description”

Checks for unrestricted inbound Telnet access (TCP port 23) in Amazon EC2 security groups, highlighting potential security risks.

YAML Source

Section titled “YAML Source”
id: ec2-unrestricted-telnet
info:
  name: Restrict EC2 Telnet Access
  author: princechaddha
  severity: critical
  description: |
    Checks for unrestricted inbound Telnet access (TCP port 23) in Amazon EC2 security groups, highlighting potential security risks.
  impact: |
    Unrestricted Telnet access can expose EC2 instances to unauthorized access and potential security breaches.
  remediation: |
    Restrict inbound Telnet access by updating EC2 security group rules to allow only trusted IP ranges or disabling Telnet if not required.
  reference:
    - https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/authorizing-access-to-an-instance.html
  tags: cloud,devops,aws,amazon,ec2,aws-cloud-config


variables:
  region: "us-east-1"


self-contained: true
code:
  - engine:
      - sh
      - bash
    source: |
      aws ec2 describe-security-groups --region $region --filters Name=ip-permission.from-port,Values=23 Name=ip-permission.to-port,Values=23 Name=ip-permission.cidr,Values='0.0.0.0/0' --output json --query 'SecurityGroups[*].GroupId'


    extractors:
      - type: json
        name: securitygroup
        internal: true
        json:
          - '.[]'


      - type: dsl
        dsl:
          - 'securitygroup + " security group(s) alows unrestricted access (0.0.0.0/0 or ::/0) on TCP port 23"'
# digest: 4a0a00473045022100ef17451433471bd35263e1eb314c2a1c6e85ed124c2e62659576272b21ecd78e02206b57de436186c1d141bd7d5bf3479fdbcc8a7273b0057d9349f9f3f3e4b6f5be:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

Section titled “Guide to check the vulnerabilities”

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

Terminal window
$ nuclei -u "URL" -t "cloud/aws/ec2/ec2-unrestricted-telnet.yaml"

View on Github