---
title: Security group with unrestricted access to SSH
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Infrastructure as Code (IaC)
  Security > IaC Security Rules > Security group with unrestricted access to SSH
---

# Security group with unrestricted access to SSH

{% callout %}
# Important note for users on the following Datadog sites: app.ddog-gov.com, us2.ddog-gov.com

{% alert level="danger" %}
This product is not supported for your selected [Datadog site](https://docs.datadoghq.com/getting_started/site.md). ({% placeholder "user-datadog-site-name" /%}).
{% /alert %}

{% /callout %}

## Metadata{% #metadata %}

**Id:** `terraform-aws-security-group-with-unrestricted-access-to-ssh` 

**Provider:** AWS

**Platform:** Terraform

**Severity:** Medium

**Category:** Networking and Firewall

#### Learn More{% #learn-more %}

- [Provider Reference](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group)

### Description{% #description %}

This check verifies that AWS security groups do not allow unrestricted inbound access to port 22 (SSH) from the public internet (`cidr_blocks = ["0.0.0.0/0"]`). Allowing public SSH access exposes instances to unauthorized access attempts and automated attacks, increasing the risk of successful brute-force compromises. To mitigate this vulnerability, the `cidr_blocks` attribute in the `ingress` block should be restricted to trusted IP ranges only, as shown below:

Insecure configuration:

```
ingress {
  from_port   = 22
  to_port     = 22
  protocol    = "tcp"
  cidr_blocks = ["0.0.0.0/0"]
}
```

Secure configuration:

```
ingress {
  from_port   = 22
  to_port     = 22
  protocol    = "tcp"
  cidr_blocks = ["192.120.0.0/16", "75.132.0.0/16"]
}
```

If left unaddressed, this misconfiguration can lead to remote attackers gaining entry to instances via SSH, putting sensitive data and critical infrastructure at risk.

## Compliant Code Examples{% #compliant-code-examples %}

```terraform

resource "aws_security_group" "negative1" {
  name        = "allow_tls"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["192.120.0.0/16", "75.132.0.0/16"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "allow_tls"
  }
}
```

```terraform
module "vote_service_sg" {
  source = "terraform-aws-modules/security-group/aws"
  version = "4.3.0"
  name        = "user-service"
  description = "Security group for user-service with custom ports open within VPC, and PostgreSQL publicly open"
  vpc_id      = "vpc-12345678"

  ingress {
    description = "TLS from VPC"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["192.120.0.0/16", "75.132.0.0/16"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "allow_tls"
  }
}
```

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```terraform
resource "aws_security_group" "positive1" {
  name        = "allow_tls"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "allow_tls"
  }
}
```

```terraform
resource "aws_security_group" "positive2" {
  name        = "allow_tls"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["192.120.0.0/16", "0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "allow_tls"
  }
}
```

```terraform
module "vote_service_sg" {
  source = "terraform-aws-modules/security-group/aws"
  version = "4.3.0"
  name        = "user-service"
  description = "Security group for user-service with custom ports open within VPC, and PostgreSQL publicly open"
  vpc_id      = "vpc-12345678"

  ingress {
    description = "TLS from VPC"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "allow_tls"
  }
}
```