AWS CLI listing S3 buckets gives SignatureDoesNotMatch error using IAM user credentials

Question

I am using AWS CLI on Ubuntu 16.04 LTS, I am trying to list all buckets. In aws configure I have input the IAM user access key and IAM user secret key. This IAM user has permissions to list buckets and can list buckets in the console. But using AWS CLI with these keys and running the command aws s3 ls, it is giving me this error:

A client error (SignatureDoesNotMatch) occurred when calling the ListBuckets operation: The request signature we calculated does not match the signature you provided. Check your key and signing method.

I have created a policy to list buckets for this particular IAM user also.

I want to perform further sync operations and make all files public operations via a shell script using this IAM user credentials and do not want to use root credentials.

Answer 1

Found my issue. I had old AWS keys in my environment variables. If you have environment variables named

AWS_SECRET_ACCESS_KEY
AWS_ACCESS_KEY_ID

the awscli will use those values instead of what is provided via ~/.aws/credentials.

Try running printenv | grep AWS and verify that those values aren't set. If so then just run a

unset AWS_SECRET_ACCESS_KEY
unset AWS_ACCESS_KEY_ID

and you should be good to go.

Answer 2

In my case, this was due to incorrect aws_secret_access_key.

To check, open the file ~/.aws/credentials by typing:

cat ~/.aws/credentials

The content should be something like below:

[default]
aws_access_key_id = xxx
aws_secret_access_key = xx

See if the aws_access_key_id & aws_secret_access_key matches your credentials. If it doesn't, edit and save changes.

p/s: If you don't remember your aws_secret_access_key, generate a new key and secret by going to aws console --> your name --> My Security Credentials.

Then click 'Create access key':

Take note that you can only have two access keys at a time.