Amazon Web Services (AWS) Identity & Access Management (IAM) is a foundational service that provides security in the cloud. It allows you to manage access to your AWS services, resources, and applications. It’s a core service for AWS, but nothing’s perfect. And while using it, you may encounter errors. But don’t sweat it! Let’s dig into the cause and resolution for five common AWS IAM errors. Show Accelerate your career in cloud A Cloud Guru makes it easy (and awesome) to level up your cloud career — even if you’re totally new to tech. Check out ACG’s current free courses or get started now with a free trial. 1. AccessDeniedException – I Can’t Assume a RoleIAM roles can be used to delegate access to your AWS resources across different AWS accounts that you own. For example, you can share resources in one account with users in a different account. This is made possible by establishing trust relationships between the trusting account and your other AWS trusted accounts. Let’s take the case where you want to give users in your development account access to resources in your production account. This could be a case where there is a need to promote an update made in development to production. This type of access is called cross-account access. If permissions aren’t set up correctly, you may encounter the error below. Error Cause Assuming you’ve already created a role in your production account that a user in your development account can assume (to retrieve temporary security credentials), consider the solutions below. Solution #1 Solution #2 Upon success of assuming the role, the AssumeRole API returns a set of temporary security credentials that can be used to access the production account with the permissions specified in role. 2. AccessDeniedException – I Can’t Call an AWS API OperationWhen providing access to resources in your AWS account, consider the principle of least-privileged permissions. Least-privileged permissions grant only the minimum level of access necessary to perform a given task. This principle highlights the fact that users and services cannot access resources until access is explicitly granted. Let’s take the case of a user attempting to call the list bucket operation on an Amazon S3 bucket using the command line interface. The user is met with the error below. Error Cause Solution To provide an additional level of security, you can name objects in the Resource element instead of using the wildcard *, which represents all resources. If you’re not familiar with the Resource element, it specifies the object or objects that the policy covers. The example below allows access to all items within a specific Amazon S3 bucket using the Resource, the Amazon Resource Name (ARN), and the wildcard *. { "Version": "2012-10-17", "Statement": [ { "Sid": "VisualEditor0", "Effect": "Allow", "Action": [ "s3:ListAllMyBuckets", "s3:ListBucket", "s3:HeadBucket" ], "Resource": "arn:aws:s3:::bucket_name/*" } ] }Let’s start your AWS journeyLooking to get AWS certified or level up your cloud career? Learn in-demand AWS skills by doing — with ACG. 3. UnauthorizedOperation – I am not Authorized to Perform an OperationWhen attempting to perform an operation, you may see an error stating you’re not authorized to perform that operation. Let’s take the case of listing EC2 instances in an account using the describe-instances action. Error Cause Solution It is important to highlight that the DescribeInstances action cannot be defined with an ARN in the Resource element. Some services do not allow you to specify actions for individual resources and require that you use the wildcard * in the Resource element instead. While you can define resource level permissions for a subset of the EC2 APIs, the DescribeInstances action currently does not support resource level permissions. In this case, if you add an ARN number to the Resource element, you will continue to see the UnauthorizedOperation error. Want to Prevent the deletion of an Amazon S3 Bucket? Use the AWS Policy Generator tool to create policies that control access to AWS products and resources! 4. One Service is Not Authorized to Perform an Action on Another ServiceWhen managing your AWS resources, you often need to grant one AWS service access to another service to accomplish tasks. Let’s take the case where you need to query a DynamoDB table from a Lambda function. The following Lambda code snippet, to query the USERS table, results in the error shown below. table = boto3.resource('dynamodb').Table('USERS') response = table.query(KeyConditionExpression=Key('USER_ID').eq(userid))Error Cause Solution The same method can be followed to allow Lambda access to Amazon S3. The method described above will work if the Lambda function and S3 bucket are in the same AWS account. However, if they are in different accounts, you will need to grant Amazon S3 permissions on both the Lambda execution role and the bucket policy. 5. The policy must contain a valid version stringWhen creating or modifying a policy, you may encounter an error that states the policy must contain a valid Version string. This Version policy element is not the same as multiple version support for managed policies. The Version policy element specifies the language syntax rules that should be used to process the policy. This can be a point of confusion for those new to IAM as they often try to use the current date for the Version policy element; however, the Version is limited to a few select values. For example, using the current date for the Version string, similar to what’s shown below, will cause an error. { "Version": "2020-07-30", "Statement": [ { "Sid": "VisualEditor0", "Effect": "Allow", "Action": [ "ec2:DescribeInstances" ], "Resource": "*" } ] }Error Cause Solution
If you do not include a Version element, the value defaults to 2008-10-17. Learn more about IAMWell, there you have it! We’ve reviewed some of the common errors along with resolutions that you may encounter when using IAM. Looking for more details and tips to help you troubleshoot other errors with IAM? Check out my new introductory course around IAM, Identity and Access Management (IAM) Concepts. And if you want to learn more about IAM in Azure, check out free-for-the-month-of-October course IAM for Azure. It’s one of the two dozen free cloud courses available with A Cloud Guru’s free tier. There’s more where that came from! A Cloud Guru offers learning paths, quizzes, certification prep, and more. How do I check permissions on my S3?Open the Amazon S3 console at https://console.aws.amazon.com/s3/ . Select the bucket that you want AWS Config to use to deliver configuration items, and then choose Properties. Choose Permissions.
Can SageMaker connect to S3?The lifecycle configuration accesses the S3 bucket via AWS PrivateLink. This architecture allows our internet-disabled SageMaker notebook instance to access S3 files, without traversing the public internet.
How do I give permission to an S3 bucket?To set ACL permissions for a bucket
Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/ . In the Buckets list, choose the name of the bucket that you want to set permissions for. Choose Permissions. Under Access control list, choose Edit.
How do I know if I have access to S3 bucket?Preview access
In the S3 console, open the Edit bucket policy page and draft a policy, as shown in Figure 1. Under Preview external access, choose an existing account analyzer from the drop-down menu and then choose Preview. Access Analyzer generates a preview of findings for access to your bucket.
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