Group With Privilege Escalation By Actions 'iam:UpdateAssumeRolePolicy' And 'sts:AssumeRole'

• Query id: 78f1ec6f-5659-41ea-bd48-d0a142dce4f2
• Query name: Group With Privilege Escalation By Actions 'iam:UpdateAssumeRolePolicy' And 'sts:AssumeRole'
• Platform: Terraform
• Severity: Medium
• Category: Access Control
• URL: Github

Description

Group with privilege escalation by actions 'iam:UpdateAssumeRolePolicy' and 'sts:AssumeRole' and Resource set to '*'. For more information see https://rhinosecuritylabs.com/aws/aws-privilege-escalation-methods-mitigation/.
Documentation

Code samples

Code samples with security vulnerabilities

Postitive test num. 1 - tf file

resource "aws_iam_group" "cosmic" {
  name = "cosmic"
}

resource "aws_iam_group_policy" "test_inline_policy" {
  name = "test_inline_policy"
  group = aws_iam_group.cosmic.name

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = [
          "iam:UpdateAssumeRolePolicy",
        ]
        Effect   = "Allow"
        Resource = "*"
      },
    ]
  })
}


resource "aws_iam_policy_attachment" "test-attach" {
  name       = "test-attachment"
  groups     = [aws_iam_group.cosmic.name]
  policy_arn = aws_iam_policy.policy.arn
}


resource "aws_iam_policy" "policy" {
  name        = "test-policy"
  description = "A test policy"

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = [
          "sts:AssumeRole",
        ]
        Effect   = "Allow"
        Resource = "*"
      },
    ]
  })
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "aws_iam_user" "cosmic2" {
  name = "cosmic2"
}

resource "aws_iam_user_policy" "inline_policy_run_instances2" {
  name = "inline_policy_run_instances"
  user = aws_iam_user.cosmic2.name

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = [
          "ec2:Describe*",
        ]
        Effect   = "Allow"
        Resource = "*"
      },
    ]
  })
}