S3 full-access configuration from EC2 instance [duplicate] - amazon-web-services

This question already has answers here:
What is Wrong With My AWS Policy?
(2 answers)
Closed 4 years ago.
I've created a role to grant full access to S3 from an EC2 instance. This is working ok, every time I create a new EC2 instance and attach this role it has full access to all my buckets on S3. I feel this is quite insecure, so my question is: is it possible to create a role or something similar to grant EC2 instances full access to specific buckets on S3 and not to all of them? Thanks!
This is the role I have right now:
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "s3:*",
"Resource": "*"
}
]

Already answered by me HERE
You can try this policy to give full access to a particular bucket:
{
"Version": "2012-10-17",
"Statement": [{
"Action": "s3:*",
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::<BUCKETNAME>/*"
]
},
{
"Effect": "Allow",
"Action": "s3:ListAllMyBuckets",
"Resource": "arn:aws:s3:::*"
}
]
}

Related

AWS S3 Access Policy - Restricting Folder Access

I am having trouble with AWS S3 Policies.
Essentially I have a bucket for Client Backups. I'm now automating them and have set up users for each client.
I want each client to have access to their own folder for uploading backups within the main bucket. But I don't want them to have access to other clients. I am struggling to get any policy I find to do this.
This is access via WINSCP S3 and using a Wordpress backup plugin. Not sure if this relates to anything or not.
Is anyone able to guide or help with this? I've tried multiple templates with no success. Could someone give me something?
{
"Version":"2012-10-17",
"Statement": [
{
"Sid": "AllowUserToSeeBucketListInTheConsole",
"Action": ["s3:ListAllMyBuckets", "s3:GetBucketLocation"],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::*"]
},
{
"Sid": "AllowRootAndHomeListingOfCompanyBucket",
"Action": ["s3:ListBucket"],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::BUCKETNAME"],
"Condition":{"StringEquals":{"s3:prefix":["","CLIENTNAME/"],"s3:delimiter":["/"]}}
},
{
"Sid": "AllowListingOfUserFolder",
"Action": ["s3:ListBucket"],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::BUCKETNAME"],
"Condition":{"StringLike":{"s3:prefix":["CLIENTNAME/*"]}}
},
{
"Sid": "AllowAllS3ActionsInUserFolder",
"Effect": "Allow",
"Action": ["s3:*"],
"Resource": ["arn:aws:s3:::BUCKETNAME/CLIENTNAME/*"]
}
]
}
Thanks.
Please approach this a bit differently.
You want to create a group and programatically add desired users to that group.
Then you want to create a custom role with your desired permissions.
Then you attach the role to the group once. And then rest your automation will take care.

What is Wrong With My AWS Policy?

I am trying to give a programmatic IAM user access to a single bucket.
I setup the following policy and attached it to the user:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:ListBucket"
],
"Resource": [
"arn:aws:s3:::mybucket"
]
},
{
"Effect": "Allow",
"Action": [
"s3:PutObject",
"s3:GetObject",
"s3:DeleteObject"
],
"Resource": [
"arn:aws:s3:::mybucket/*"
]
}
]
}
Trying to programatically upload a file I got a 403.
I got this policy from here:
Writing IAM Policies: How to Grant Access to an Amazon S3 Bucket
I verified that everything else is working by then adding an AWS managed policy, AmazonS3FullAccess, after which my upload succeeded. But I would rather not give this user full access.
There are no other policies attached to this user.
Nothing is wrong with your policy. Make sure you're using the right bucket name in the IAM policy and to add the policy to the user.
You can test it with IAM Policy Simulator. Maybe you should consider the time to policies take effect, but it's "almost immediately". See this answer.
You can try this policy to give full access to a particular bucket:
{
"Version": "2012-10-17",
"Statement": [{
"Action": "s3:*",
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::<BUCKETNAME>/*"
]
},
{
"Effect": "Allow",
"Action": "s3:ListAllMyBuckets",
"Resource": "arn:aws:s3:::*"
}
]
}
Since you are providing Put, Get, Delete, You might as well provide full access to the particular bucket.

How to Give Amazon SES Permission to Write to Your Amazon S3 Bucket

I want my SES(AWS) can receive emails, so I follow the following tutorial,
http://docs.aws.amazon.com/ses/latest/DeveloperGuide/receiving-email-getting-started-receipt-rule.html
When I am at last step - creating rule, it comes with following error,
Could not write to bucket: "email-receiving"
I google and found this information on (http://docs.aws.amazon.com/ses/latest/DeveloperGuide/receiving-email-permissions.html) can fix the issue.
However, when adding my policy statement, it comes with an error - This policy contains the following error: Has prohibited field Principal For more information about the IAM policy grammar, see AWS IAM Policies.
My policy statement is,
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "GiveSESPermissionToWriteEmail",
"Effect": "Allow",
"Principal": {
"Service": [
"ses.amazonaws.com"
]
},
"Action": [
"s3:PutObject"
],
"Resource": "arn:aws:s3:::mybulketname/*",
"Condition": {
"StringEquals": {
"aws:Referer": "my12accountId"
}
}
}
]
}
If I take off
"Principal": {
"Service": [
"ses.amazonaws.com"
]
}
Validate policy will pass.
Thanks
Find bucket->permission->bucketPolicy
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AllowSESPuts",
"Effect": "Allow",
"Principal": {
"Service": "ses.amazonaws.com"
},
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::BUCKEN_NAME/*",
"Condition": {
"StringEquals": {
"aws:Referer": "YOUR ID"
}
}
}
]
}
Read more here https://docs.aws.amazon.com/ses/latest/DeveloperGuide/receiving-email-permissions.html
To find your AWS account ID number on the AWS Management Console, choose Support on the navigation bar on the upper-right, and then choose Support Center. Your currently signed-in account ID appears in the upper-right corner below the Support menu.
Read more here https://docs.aws.amazon.com/IAM/latest/UserGuide/console_account-alias.html
I follow this advice but I was still having the issue. After much debugging, I realized that SES was failing to write because I had default server-side encryption (on the bucket) set to "AWS-KMS"
I did a 5 minute google search and couldn't find this incompatibility documented anywhere.
You can work around this by updating your default encryption setting on the target bucket to either "AES-256" or "None".
This problem has been resolved.
Create the policy on the bucket you want to grant the SES permission, not in the IAM
Note, I continued to have this error even after correctly specifying permissions. If you are using cross-region (e.g. SES is in N Virginia and S3 Bucket is in Africa) then you either need to specify the bucket name with the region or else just make the bucket in the same region.
I have the same problem, if I only delete the "Condition"
the policy passes and the "RuleSet" is Ok:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "GiveSESPermissionToWriteEmail",
"Effect": "Allow",
"Principal": {
"Service": "ses.amazonaws.com"
},
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::mybulketname/*"
}
]
}

Granting access to S3 resources based on role name

IAM policy variables are quite cool and let you create generic policys to, for example, give users access to paths in an S3 bucket based on their username, like this:
{
"Version": "2012-10-17",
"Statement": [
{
"Action": ["s3:GetObject","s3:PutObject","s3:DeleteObject"],
"Effect": "Allow",
"Resource": "arn:aws:s3:::fooCorp-user-files/${aws:username}/*"
},
{
"Action": "s3:ListBucket",
"Effect": "Allow",
"Resource": "arn:aws:s3:::fooCorp-user-files"
}
]
}
My question is, how can this be done using roles (attached to EC2 instances) instead of user accounts?
I have a number of app servers with unique IAM user accounts that are linked to a generic policy similar to the one above. This isolates the files accessible by each user/app without creating multiple policies.
I want switch these servers to use roles instead but there doesn't seem to be an equivalent IAM variable like aws:rolename.
The docs indicate that when using a role assigned to an EC2 instance the aws:username variable isn't set and aws:userid is [role-id]:[ec2-instance-id] (which isn't helpful either).
This really seems like something you should be able to do.. or am I coming at this the wrong way?
I've been looking for the same and after a lot of searching my conclusion was that it is not possible to use the role name as a variable in a IAM policy (I'd love to be proven wrong though).
Instead, I tagged my role with a name and ended up with this:
{
"Version": "2012-10-17",
"Statement": [
{
"Action": ["s3:GetObject","s3:PutObject","s3:DeleteObject"],
"Effect": "Allow",
"Resource": "arn:aws:s3:::fooCorp-user-files/${aws:PrincipalTag/name}/*"
},
{
"Action": "s3:ListBucket",
"Effect": "Allow",
"Resource": "arn:aws:s3:::fooCorp-user-files"
}
]
}
(Cross-posted to AWS S3 IAM policy for role for restricting few instances to connect to S3 bucket based in instance tag or instance id)
Instead of using aws:SourceArn, use aws:userid!
The Request Information That You Can Use for Policy Variables documentation that you mentioned has a table showing various values of aws:userid including:
For Role assigned to an Amazon EC2 instance, it is set to role-id:ec2-instance-id
Therefore, you could use the Role ID of the role that is used to launch the Amazon EC2 instance to permit access OR the Instance ID.
For example, this one is based on a Role ID:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "SID123",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"*"
],
"Condition": {
"StringLike": {
"aws:userid": [
"AROAIIPEUJOUGITIU5BB6*"
]
}
}
}
]
}
Of course, if you are going to assign permission based on a Role ID, then you can just as easily grant permissions within the Role itself.
This one is based on an Instance ID:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "SID123",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"*"
],
"Condition": {
"StringLike": {
"aws:userid": [
"*:i-03c9a5f3fae4b630a"
]
}
}
}
]
}
The Instance ID will remain with the instance, but a new one will be assigned if a new instance is launched, even from the same Amazon Machine Image (AMI).

AWS IAM EC2 Access to Instance ID [duplicate]

This question already has an answer here:
how to show specific ec2 instance for an user
(1 answer)
Closed 7 years ago.
Trying to setup a user to only be able to access one type of instance and only be abled to stop and start the instance. But when I setup a policy for it the i just get an error saying not authorized:
An error occurred fetching instance data: You are not authorized to perform this operation.
Account ID was retrieved from security page.
For the sake of testing i have allowed all actions (ec2:*) and tried these policy's
{
"Version": "2012-10-17",
"Statement": [
{
"Action": "ec2:*",
"Effect": "Allow",
"Resource": "arn:aws:ec2:us-east-1:XXXXXXXXXX:instance/i-XXXXXXX"
}
]
}
with tag dev
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1411556016000",
"Effect": "Allow",
"Action": [
"ec2:StartInstances",
"ec2:StopInstances"
],
"Resource" : "*"
"Condition": {
"ArnEquals": {
"ec2:ResourceTag/Environment": "dev"
}
}
}
]
}
This is probably a duplicate of this question, but to answer, you probably also need to give DescribeInstances permissions.