Critical IP Ports are Open: Identification, View and Set Security Groups Rules

Critical IP Ports are Open: Identification, View and Set Security Groups Rules

Identification

Our identification of the issue is based on the following data:

  • One or more security groups were configured to allow access through critical IP ports.
  • One or more of your AWS instances are using the security group with the open critical IP ports.
Newvem Group Security Assessment 

The following is a list of critical IP ports:

Port # Subject
5432 Postgres
3306 MySql
3362 MySql
1433 Sql Server
389 LDAP
9160 Cassandra
27170 MongoDB
5672 AMQP
11211 Memcached
Instructions
Viewing a Security Group’s Rules
  •  AWS Management Console
    1. Log in to the AWS Management Console and click the Amazon EC2 tab.
    2. In the Navigation pane, click Security Groups. The security groups belonging to the account are displayed.
    3. Select the security group whose rules you want to see. The security group’s information is displayed in the lower pane in the Details tab; its rules are displayed in the Inbound tab.
  • Using AWS CLI Command Line Tools - 

 Type the command:

PROMPT>  ec2-describe-group [group ...]

Amazon EC2 returns output in the format of the following example.

GROUP   sg-251s6f45     999988887777    WebServers   web

PERMISSION      999988887777    WebServers ALLOWS  tcp     80      80      FROM    CIDR    0.0.0.0/0       ingress

Tip: To filter the list to return only the security group with the open ports, use the ip-permission.from-port and ip-permission.to-port filters.

Note: These are a short explanations based on our detailed how-to guide - How to Add a Rule to an AWS Security Group


Adding a Rule to a Security Group

AWS Management Console

To add a rule to a security group -

  1.  In the AWS Management Console, select a specific EC2 security group, by following the instructions in the above procedure (Viewing a security group’s rules). The selected security group’s rules appear in the lower pane, in the Inbound tab.
  2. In the Inbound tab, in Create a new rule, select the type of rule to create.
  3. In Port range, specify a port or port range. In this case of open critical IP ports, we suggest that you reduce the number of open ports to a minimum, limiting access from the outside world only to web-facing services (e.g. port 80 for HTTP and port 443 for HTTPS).
  4. In Source, specify one of the following:
    • The name or ID of the security group that is allowed access. If the group is in someone else’s AWS account, type the AWS account ID that contains the security group, followed by “/”, followed by the security group name. For example:  978644442091/SecurityGroupA.
    • The IP address or range of addresses in CIDR notation that is allowed access. For example, 123.2.432.3 to limit access to one computer at that IP address; 123.2.432.3/24 to limit access to a network at that range of IP addresses. You can enter 0.0.0.0/0 to allow all IP addresses to access the specified port range.

5. Click Add Rule. An asterisk appears on the Inbound tab, and the Apply Rule Changes button becomes enabled.

6. Click Apply Rule Changes. The new rule is created and can be viewed in the right pane of the Inbound tab. The new rule is applied to all instances belonging to the selected security group.

Note: These are a short explanations based on our detailed how-to guide - How to Add a Rule to an AWS Security Group


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Keywords: critical IP ports, amazon aws security groups, AWS management console, security group rule, amazon ec2, aws instances,

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