Sensitive Port Is Exposed To Small Public Network

• Query id: e35c16a2-d54e-419d-8546-a804d8e024d0
• Query name: Sensitive Port Is Exposed To Small Public Network
• Platform: Terraform
• Severity: Medium
• Category: Networking and Firewall
• URL: Github

Description

A sensitive port, such as port 23 or port 110, is open for a small public network in either TCP or UDP protocol
Documentation

Code samples

Code samples with security vulnerabilities

Postitive test num. 1 - tf file

resource "aws_security_group" "positive1" {
  name        = "allow_tls1"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 2200
    to_port     = 2500
    protocol    = "-1"
    cidr_blocks = ["12.0.0.0/25"]
  }
}


resource "aws_security_group" "positive2" {
  name        = "allow_tls2"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 20
    to_port     = 60
    protocol    = "tcp"
    cidr_blocks = ["1.2.3.4/26"]
  }
}


resource "aws_security_group" "positive3" {
  name        = "allow_tls3"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 5000
    to_port     = 6000
    protocol    = "-1"
    cidr_blocks = ["2.12.22.33/27"]
  }
}


resource "aws_security_group" "positive4" {
  name        = "allow_tls4"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 20
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["10.92.168.0/28"]
  }
}


resource "aws_security_group" "positive5" {
  name        = "allow_tls5"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 445
    to_port     = 500
    protocol    = "udp"
    cidr_blocks = ["1.1.1.1/29","0.0.0.0/0",  "2.2.3.4/12"]
  }
}


resource "aws_security_group" "positive6" {
  name        = "allow_tls6"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 135
    to_port     = 170
    protocol    = "udp"
    cidr_blocks = ["10.68.0.0", "0.0.0.0/28"]
  }
}


resource "aws_security_group" "positive7" {
  name        = "allow_tls7"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 2383
    to_port     = 2383
    protocol    = "udp"
    cidr_blocks = ["/0", "1.2.3.4/27"]
  }
}


resource "aws_security_group" "positive8" {
  name        = "allow_tls8"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["10.68.0.0/26"]
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "aws_security_group" "negative1" {
  name        = "allow_tls1"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 2383
    to_port     = 2383
    protocol    = "tcp"
    cidr_blocks = [aws_vpc.main.cidr_block]
  }
}


resource "aws_security_group" "negative2" {
  name        = "allow_tls2"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 2384
    to_port     = 2386
    protocol    = "tcp"
    cidr_blocks = ["/0"]
  }
}


resource "aws_security_group" "negative3" {
  name        = "allow_tls3"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 25
    to_port     = 2500
    protocol    = "tcp"
    cidr_blocks = ["1.2.3.4/0"]
  }
}


resource "aws_security_group" "negative4" {
  name        = "allow_tls4"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 25
    to_port     = 2500
    protocol    = "tcp"
    cidr_blocks = ["1.2.3.4/5"]
  }
}


resource "aws_security_group" "negative5" {
  name        = "allow_tls5"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 25
    to_port     = 2500
    protocol    = "udp"
    cidr_blocks = ["1.2.3.4/5","0.0.0.0/12"]
  }
}


resource "aws_security_group" "negative6" {
  name        = "allow_tls6"
  description = "Allow TLS inbound traffic"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "TLS from VPC"
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["1.2.3.4","0.0.0.0/0"]
  }
}