I have an Amazon S3 bucket that is being used by CloudTrail.
However, the S3 bucket is not visible in S3.
When I click on the bucket in CloudTrail, it links to S3 but I get access denied.
The bucket is currently in use by CloudTrail, and based on the icons that seems to be working fine.
So, it seems this is an existing bucket but I cannot access it!
I also tried to access the S3 bucket with the root account, but the same issue occurs there.
Please advise on how I would regain access.
Just because cloudtrail has access to the bucket, doesn't mean your account also does.
You would need to talk to whoever manages your security and request access. or if this is your account, make sure you are logged in with credentials that have the proper access.
Related
I am kinda new to S3 and I am aware that access to my bucket/objects can be given either through bucket policy or acl. The thing is that acl access can be given per object, so it is not clear to me how to fully review who was given access, even to a single object in the bucket. My question is how can I easily and accurately evaluate that either from the aws web management console or from boto3, in order to ensure that I am the only one who has access to my bucket and all of its objects.
It's not easy.
First, let's review the ways that permission might be granted:
Access Control Lists (ACLs) are object-level permissions that can grant public access, or access to a specific user. They are a remnant of the early way that Amazon S3 worked and can be annoying to manage. In fact, a new feature was recently made available that allows ACLs to be disabled -- and that's what AWS recommends!
Bucket Policies allow permissions to be assigned to a bucket, or a path within a bucket. This is a great way to make a bucket public and the only way to provide cross-account access to a bucket.
IAM Policies can be applied to an IAM User, IAM Group or IAM Role. These policies can grant permission to access Amazon S3 resources within the same account. This is a great way to assign permissions to specific IAM Users rather than doing it via a Bucket Policy.
The Amazon S3 console does allow you to Review bucket access using Access Analyzer for S3:
Access Analyzer for S3 alerts you to S3 buckets that are configured to allow access to anyone on the internet or other AWS accounts, including AWS accounts outside of your organization. For each public or shared bucket, you receive findings into the source and level of public or shared access. For example, Access Analyzer for S3 might show that a bucket has read or write access provided through a bucket access control list (ACL), a bucket policy, a Multi-Region Access Point policy, or an access point policy. Armed with this knowledge, you can take immediate and precise corrective action to restore your bucket access to what you intended.
However, it won't give you a full list of who can access which buckets.
You want to "ensure that you are the only one who has access to the bucket" -- this would require checking the Bucket Policy and the permissions of all IAM Users. There's no short-cut for doing this.
I think the other answer answers most of the options in a very good detail.
But usually each bucket contains either public data, non-public data or sensitive data. For any bucket which should not contain public data just disable it and the CloudFormation
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-s3-bucket.html
mentions this https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-s3-bucket-publicaccessblockconfiguration.html for restricting public access.
Additionally the bucket supports encryption, when you allow KMS encryption you can also control access to data via the KMS key. That is something worth to consider for sensitive data.
Otherwise - yes, it is really hard to make sure there is no policy in the account which would not allow any user in your account to get access to something they should not have access to. One way how to do it may be to just control who can modify the the IAM policies (the iam:* permissions). There are also automatic tools to control policies and find vulnerabilities. For just one purpose it is not that hard to create one too.
Even if the bucket is completely private, the objects can be made public by other means - typically via CloudFront.
From petrch's answer
Otherwise - yes, it is really hard to make sure there is no policy in the account which would not allow any user in your account to get access to something they should not have access to
At least, it will be simpler now.
From "Controlling ownership of objects and disabling ACLs for your bucket":
Starting in April 2023, Amazon S3 will change the default settings for S3 Block Public Access and Object Ownership (ACLs disabled) for all new S3 buckets.
For new buckets created after this update,
all S3 Block Public Access settings will be enabled, and
S3 access control lists (ACLs) will be disabled.
These defaults are the recommended best practices for securing data in Amazon S3.
You can adjust these settings after creating your bucket.
For more information, see Default settings for new S3 buckets FAQ and Heads-Up: Amazon S3 Security Changes Are Coming in April of 2023 in the AWS News Blog.
This might be a stupid question, but I've never used AWS before.
So apparently, to create an AWS account I need to give my credit card information, but I don't want to do that.
Is there any other way to access the information from this link?:
https://s3.console.aws.amazon.com/s3/buckets/quizdb-public/?region=us-east-1&tab=overview
The URL https://s3.console.aws.amazon.com/s3/buckets/quizdb-public/?region=us-east-1&tab=overview
is the link that will be shown in the address bar when you log into the AWS console, go to S3 and click on the bucket. If you do not have access to that specific AWS account and the AWS console you will not be able to access the information in the bucket with that URL.
I need to quickly deploy a static angular app to AWS S3. Unfortunately, I am still new to id so I would like to ask your help on:
What should be the bucket policy?
What roles should I give a user group to access it?
Requirements:
App deployed in the S3 bucket is public
Bucket contents should only accessible by those part of a user group. The users of the group should only be able to upload and get files in the bucket. Nothing more nothing less.
Another user group as administrators of the bucket.
Thanks. Any help would be appreciated.
Have you read Hosting a static website using S3? That should answer your question about bucket policy.
IAM users will need the appropriate S3 permissions on the bucket. This is an example of a read-write policy; remove the s3:PutObject and s3:DeleteObject permissions for read-only access.
As luk2302 pointed out, if you want to publish the S3 URL as your website URL, then the bucket contents must be publicly readable. If you want to publish the app using a custom domain name and/or use HTTPS, you should consider adding a CloudFront distribution. Doing so would also allow you to keep the bucket contents private so only your IAM users have direct access to the bucket.
I have provided AmazonS3FullAccess policy for both the IAM user and group. Also the buket that I am trying to access says "Objects can be public". I have explicitly made the folder inside the bucket public. Despite all this I am getting access denied error when I tried to access it through its url. Any idea on this?
Objects in Amazon S3 are private by default. This means that objects are not accessible by anonymous users.
You have granted permission for your IAM User to be able to access S3. Therefore, you have access to the objects but you must identify yourself to S3 so that it can verify your identity.
You should be able to access S3 content:
Via the Amazon S3 management console
Using the AWS CLI (eg aws s3 ls s3://bucketname)
Via authenticated requests in a web browser
I suspect that you have been accessing your bucket via an unauthenticated request (eg bucketname.s3.amazonaws.com/foo.txt. Unfortunately, this does not tell Amazon S3 who you are, so it will deny the request.
To access content with this type of URL, you can generate an Amazon S3 pre-signed URLs, which appends some authentication information to the URL to prove your identity. An easy way to generate the URL is with the AWS CLI:
aws s3 presign s3://bucketname/foo.txt
It will return a URL that looks like this:
https://bucketname.s3.amazonaws.com/foo.txt?AWSAccessKeyId=AKIAxxx&Signature=xxx&Expires=1608175109
The URL will be valid for one hour by default, up to 7 days.
There are two ways I will recommend.
go to s3 dashboard, and download the object you need, one by one manually, the bucket can be kept private at the same time.
build a gateway/a small service, to handle authentication for you, set a policy and give the permission to the service container/lambda to visit the private bucket, and restrict only specific users to download the objects.
References
download from aws s3
aws policy, permission and roles
I am trying to move client data from clients S3 bucket(s3://client-bucket) to our organizations S3 bucket(s3://org-bucket) I was given access keys to the clients S3 bucket.
Using AWS CLI i am able to access S3 bucket of client as see all files. I cannot however use aws s3 mv because the profile that has access to client-bucket does not have permissions set up for org-bucket.
I am not allowed to move data to an intermediate public bucket bc of security issues/sensitivity of data.
What is the best way of making this transfer go thru? Is there a way to set up a profile in aws cli config/credentials with both the access keys to org-bucket and client-bucket?
The best way is to use the access keys in your organization to access your client's S3 bucket. Since you need to copy objects directly via the CopyObject API, your IAM user/role needs to have access to both the S3 bucket in your org AND your client's S3 bucket. Therefore, your current approach doesn't work and even AssumeRole would not work either. You can follow this guide to configure proper resource-based policies in S3.