Is there a way to restrict the IAM policy for an EC2 instance s.t. it can only run a short list of Documents - I tried restricting access to ssm:GetDocument like this:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"ssm:GetDocument"
],
"Resource": [
"arn:aws:ssm:ap-southeast-2:*:document/MyCommand"
]
}
]}
But I can run any command on the instance still including the AWS-RunPowershellScript document.
This link shows how users can be restricted with respect to ssm:sendCommand:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/delegate-commands.html
I have not found a way to restrict SendCommand based on document. If a user does not have access, you get an error like this:
User: arn:aws:iam::123456789012:user/username is not authorized to perform: ssm:SendCommand on resource: arn:aws:ec2:us-east-1:123456789012:instance/i-01234567890abcdef
This indicates that the Resource in SendCommand can be limited based on instance ids. It would be nice if one of the Conditions was a Document ARN, but so far I haven't found any way to do it (it's not a condition in the policy generator wizard).
Update: I posted this question on the AWS forums, hopefully I'll get a response: https://forums.aws.amazon.com/thread.jspa?threadID=249039
Update 2: I got a response and the solution is that to accomplish this you must use Resource to specify both what instances you allow commands to be run on, and what document the user is allowed to run. For example, this is what I ended up with:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"ssm:SendCommand"
],
"Resource": [
"arn:aws:ec2:*:123456789012:instance/*",
"arn:aws:ssm:*:123456789012:document/RestartServices"
]
}
]
}
Related
My objective is userone buckets shoud not show to other users:
s3:ListAllMyBucket
Returns a list of all buckets owned by the authenticated sender of the request. To use this operation, you must have the s3:ListAllMyBuckets permission.
This is my policy
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:CreateBucket",
"s3:ListAllMyBuckets"
],
"Resource": [
"arn:aws:s3:::*"
]
}
]
}
s3.ListAllMyBuckets is not working i don't know why?
If i misunderstand something please let me know
This Solution works but i need to know why s3:ListAllMyBuckets not working or if misunderstand something please let me know
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"arn:aws:s3:::prefix*"
]
}
]
}
So there's no concept of a 'bucket owner' in MinIO as there is in AWS S3. The s3:ListAllMyBuckets operation effectively grants access to the ListBuckets API operation.
For what you want, there are a few patterns you can explore:
Using prefixes in a bucket per user and configuring the resource as "arn:aws:s3:::${aws:username}"
Creating a bucket per-user and creating a corresponding policy for that user only granting access to that bucket
MinIO adopts S3's deny-by-default attitude, so as long as you explicitly state which resources a user has access to, the others will fall off on their own.
I want to restrict access for a specific user to see just few EC2 instances. I created a new user in IAM Roles and I attached a new Policy to it. The content of that Policy is attached below. I tried to look over documentation and to do it myself like this:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "ec2:*",
"Resource": [
"arn:aws:ec2:eu-west-1:ACCOUNT_ID:instance/i-INSTANCE_ID1",
"arn:aws:ec2:eu-west-1:ACCOUNT_ID:instance/i-INSTANCE_ID2"
]
}
]
}
I placed my region,ACCOUNT_ID(the owner id, not of the new user created) and instance-id, but when I connect with that user and I go to list all Instances I got this An error occurred fetching instance data: You are not authorized to perform this operation..
After I placed the code in JSON editor, in Policy Review step I got this message:
This policy defines some actions, resources, or conditions that do not
provide permissions. To grant access, policies must have an action
that has an applicable resource or condition. For details, choose Show
remaining Learn more
The AWS documentation mention exactly the same configuration or these examples.
I assume you connect as that user in the console (but it would be the same with CLI) Here is what I think is happening:
To list all the instances, the console most probably calls the DescribeInstances API. As per the list of action/resources/tags that can be used in IAM policy, this API does not support the resource filter in IAM.
This means your user has no authorization to list instances and they will not be shown in the console. You can validate this theory by using the CLI to request the details of a specific instance id, if my hypothesis is correct, it will be authorized.
As DescribeInstances can not be restricted by resource or tags, I don't think it is possible to filter the instance list for a user.
To have the console working, you'll need to add the following statement in your IAM policy
"Statement": [
{ your existing statement },
{
"Effect": "Allow",
"Action": "ec2:DescribeInstances",
"Resource": "*"
}
]
Please report if I was right :-) The example you mentioned in your question shows exactly that : Resources = * on DescribeInstances and Resources specific InstanceId on other operations.
The previous answer is wrong, you can Conditionally allow access to ec2:DescribeInstances by tag names. It's an AWS best practice as well. Also explicitly deny access to the ec2:CreateTags and ec2:DeleteTags actions to prevent users from creating or deleting tags to take control of the instance.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "ec2:DescribeInstances",
"Resource": "*",
"Condition": {
"StringEquals": {
"ec2:ResourceTag/UserName": "${aws:username}"
}
}
},
{
"Effect": "Deny",
"Action": [
"ec2:CreateTags",
"ec2:DeleteTags"
],
"Resource": "*"
}
]
}
DescribeInstances action does not support condition.
https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazonec2.html
I want to use ec2 instance profile to allow my python program to access a DynamoDb table. I have tested a policy by directly assigning to the user. Now I assign this same policy as a Instance Profile to ec2 instance where my job is running.
This is the policy.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"dynamodb:*"
],
"Resource": "arn:aws:dynamodb:us-east-2:913580688765:table/users"
}
]
}
Additionally I assigned a policy to the user to be able to Pass the ec2 role.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"ec2:AssociateIamInstanceProfile",
"ec2:ReplaceIamInstanceProfileAssociation"
],
"Resource": "*"
},
{
"Effect": "Allow",
"Action": "ec2:DescribeIamInstanceProfileAssociations",
"Resource": "*"
},
{
"Effect": "Allow",
"Action": "iam:PassRole",
"Resource": "*"
}
]
}
But this does not work.
What am I missing here?
I don't have the exact answer for you but I have advice on how you can progress. First off, lets recap (and can you please double check all this):
1) You have an EC2 instance running, it's assigned to an IAM role.
2) The IAM Role trust relationship contains ec2.amazonaws.com.
3) The policy granting "dynamodb:*" is attached to the role.
If this is done, that means everything should be configured properly.
At this point, i would suggest you ssh to the EC2 instance and test out the permissions. This can be done by using the AWS CLI's dynamodb API to make a list/describe/get API calls to confirm they work on the instance. If they works, it means the instance has permissions to access dynamodb and there might be something wrong with how you're using the instance profile.
It's worthy to note that not all operations are going to work on "arn:aws:dynamodb:us-east-2:913580688765:table/users" since it's a specific table rather than all the tables e.g. "arn:aws:dynamodb:us-east-2:913580688765:table/*". API calls such as list-tables won't work if the resource is a specific table. You can find a list of dynamodb api calls and weather or not they support a specific table or not in the documentation here.
I am currently trying to configure an AWS policy for CodeCommit so that only one specific repo is shown on the repository overview page in the AWS GUI.
Currently my policy looks like this:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": [
"codecommit:Merge*",
"codecommit:Post*",
"codecommit:Describe*",
"codecommit:Update*",
"codecommit:Get*",
"codecommit:Test*",
"codecommit:BatchGet*",
"codecommit:GitPull",
"codecommit:Create*",
"codecommit:Put*",
"codecommit:GitPush",
"codecommit:DeleteBranch",
"codecommit:List*"
],
"Resource": "arn:aws:codecommit:eu-central-1:12345678:mycompany.drupal.myrepo.website"
}
]
}
But on the overview page I am always running into this error:
Error
User: arn:aws:iam::123456789:user/myuser#mycompany.de is not authorized to perform: codecommit:ListRepositories
My guess is that your policy is too restrictive for the AWS system being referenced ie CodeCommit. It may require List* and/or Describe*permissions to all repos, in order to perform its basic functions, such generating a list of all current repositories in the account, as it does on the overview page.
As a test, give codecommit:List* and codecommit:Describe* permissions to Resource: "*" only, as a second policy statement, leaving the more restrictive permissions referencing the specific resource as the first statement:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "RestrictCodeCommitAccessToSingleRepo",
"Effect": "Allow",
"Action": [
"codecommit:Merge*",
"codecommit:Post*",
"codecommit:Update*",
"codecommit:Get*",
"codecommit:Test*",
"codecommit:BatchGet*",
"codecommit:GitPull",
"codecommit:Create*",
"codecommit:Put*",
"codecommit:GitPush",
"codecommit:DeleteBranch"
],
"Resource": "arn:aws:codecommit:eu-central-1:12345678:mycompany.drupal.myrepo.website"
},
{
"Sid": "AllowBasicCodeCommitAccess",
"Effect": "Allow",
"Action": [
"codecommit:Describe*",
"codecommit:List*"
],
"Resource": "arn:aws:codecommit:eu-central-1:12345678:*"
}
]
I know this does not meet your objective of listing only the specific repo authorized, but you will still have denied all Create*,Put*,Update* etc type operations to all other repos. That should meet the main security objective of restricting R/W access to all other repos except mycompany.drupal.myrepo.website.
In my permission setups for users/groups, I often allow base operations like Get* List* Describe* for users to allow basic operations in the AWS console to function, even if I am more restrictive with one or more of those resources.
Unfortunately there is no way for you to do this right now. ListRepositories in CodeCommit will not filter results by authorization, this is a common pattern across many AWS services' List APIs.
AWS ListRepositories does not support resource-level permissions. This requires a wildcard (*) for the resource.
I have followed the docs at aws http://docs.aws.amazon.com/IAM/latest/UserGuide/PolicyVariables.html
and the question at Can an aws IAM policy dynamically refer to the logged in username?
to create a policy for a user to list his own credentials under web console/users so he can generate his own keys.
user/Alpha
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Allow",
"Action":["iam:*"],
"Resource":["arn:aws:iam::{myacctnumber}:user/${aws:username}"]
}
]
}
when I attach the the policy to user/Alpha, then open a new browser and log in as user Alpha > console > users, I get the error message
We encountered the following errors while processing your request
X User: arn:aws:iam::{myacctnumber}:user/Alpha is not authorized to perform: iam ListUsers on resource: arn:aws:iam::{myacctnumber}:user/
note the user/ is not displaying the friendly name as would be expected from ${aws:username}.
I have also tried changing the policy to
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Allow",
"Action":["iam:*"],
"Resource":["arn:aws:iam::{myacctnumber}:user/Alpha"]
}
]
}
but the same error displays.
If I make one further change to the resource and make it a wildcard,
"Resource":["arn:aws:iam::{myacctnumber}:user/*"]
the full user list is displayed to to the user Alpha
Do I need extra permissions to allow a user to see only themselves?
thx
Art
The console, when displaying a list of users, uses the iam:ListUsers API call. This call cannot be restricted by resource.
Therefore, the console will function correctly if you provide a policies that permits the ListUsers call, eg:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"iam:ListUsers"
],
"Resource": [
"*"
]
}
]
}
The only other way for the user to update their own settings would be via the AWS Command-Line Interface (CLI) or an API call, since they can avoid the need to call ListUsers.