access

AWS Get Access Key Info

June 28, 2022

How to look for an access key in AWS. Find the account.

$ aws sts get-access-key-info --access-key-id AKIA8XXXXXXXXXXXXXXX
{
    "Account": "XXXXXXXXXXXX"
}

Sudoers File Explained

June 30, 2021

You are probably wondering how the sudoers file works. Here’s a simple explanation.

Command

username host=(user:group) tag:commands

Explanation

- username – the specified user allowed to run commands.
- host – the specified host the command is allowed to run.
- user – specifies which users can use the command.
- group – specifies which groups can run the command.
- tag – the option allowed. NOPASSWD
- command – the command allowed to run.

Examples

root    ALL=(ALL) ALL
username ALL=(ALL) ALL
john test=(ALL) NOPASSWD: /bin/useradd
jane ALL=(sales) NOPASSWD: /bin/sh
%sudo ALL=(ALL) ALL
%adgroup ALL=(ALL) ALL

Here’s the permission needed for an AWS user to manage their own IAM account. The policy allows them to view their own account information, change their own passwords, rotate access keys and certificates, and manage their own git credentials.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowViewAccountInfo",
            "Effect": "Allow",
            "Action": [
                "iam:GetAccountPasswordPolicy",
                "iam:GetAccountSummary"
            ],
            "Resource": "*"
        },
        {
            "Sid": "AllowManageOwnPasswords",
            "Effect": "Allow",
            "Action": [
                "iam:ChangePassword",
                "iam:GetUser"
            ],
            "Resource": "arn:aws:iam::*:user/${aws:username}"
        },
        {
            "Sid": "AllowManageOwnAccessKeys",
            "Effect": "Allow",
            "Action": [
                "iam:CreateAccessKey",
                "iam:DeleteAccessKey",
                "iam:GetAccessKeyLastUsed",
                "iam:ListAccessKeys",
                "iam:UpdateAccessKey"
            ],
            "Resource": "arn:aws:iam::*:user/${aws:username}"
        },
        {
            "Sid": "AllowManageOwnSigningCertificates",
            "Effect": "Allow",
            "Action": [
                "iam:DeleteSigningCertificate",
                "iam:ListSigningCertificates",
                "iam:UpdateSigningCertificate",
                "iam:UploadSigningCertificate"
            ],
            "Resource": "arn:aws:iam::*:user/${aws:username}"
        },
        {
            "Sid": "AllowManageOwnSSHPublicKeys",
            "Effect": "Allow",
            "Action": [
                "iam:DeleteSSHPublicKey",
                "iam:GetSSHPublicKey",
                "iam:ListSSHPublicKeys",
                "iam:UpdateSSHPublicKey",
                "iam:UploadSSHPublicKey"
            ],
            "Resource": "arn:aws:iam::*:user/${aws:username}"
        },
        {
            "Sid": "AllowManageOwnGitCredentials",
            "Effect": "Allow",
            "Action": [
                "iam:CreateServiceSpecificCredential",
                "iam:DeleteServiceSpecificCredential",
                "iam:ListServiceSpecificCredentials",
                "iam:ResetServiceSpecificCredential",
                "iam:UpdateServiceSpecificCredential"
            ],
            "Resource": "arn:aws:iam::*:user/${aws:username}"
        }
    ]
}

{ "Version": "2012-10-17", "Statement": [ { "Sid": "AllowViewAccountInfo", "Effect": "Allow", "Action": [ "iam:GetAccountPasswordPolicy", "iam:GetAccountSummary" ], "Resource": "*" }, { "Sid": "AllowManageOwnPasswords", "Effect": "Allow", "Action": [ "iam:ChangePassword", "iam:GetUser" ], "Resource": "arn:aws:iam::*:user/${aws:username}" }, { "Sid": "AllowManageOwnAccessKeys", "Effect": "Allow", "Action": [ "iam:CreateAccessKey", "iam:DeleteAccessKey", "iam:GetAccessKeyLastUsed", "iam:ListAccessKeys", "iam:UpdateAccessKey" ], "Resource": "arn:aws:iam::*:user/${aws:username}" }, { "Sid": "AllowManageOwnSigningCertificates", "Effect": "Allow", "Action": [ "iam:DeleteSigningCertificate", "iam:ListSigningCertificates", "iam:UpdateSigningCertificate", "iam:UploadSigningCertificate" ], "Resource": "arn:aws:iam::*:user/${aws:username}" }, { "Sid": "AllowManageOwnSSHPublicKeys", "Effect": "Allow", "Action": [ "iam:DeleteSSHPublicKey", "iam:GetSSHPublicKey", "iam:ListSSHPublicKeys", "iam:UpdateSSHPublicKey", "iam:UploadSSHPublicKey" ], "Resource": "arn:aws:iam::*:user/${aws:username}" }, { "Sid": "AllowManageOwnGitCredentials", "Effect": "Allow", "Action": [ "iam:CreateServiceSpecificCredential", "iam:DeleteServiceSpecificCredential", "iam:ListServiceSpecificCredentials", "iam:ResetServiceSpecificCredential", "iam:UpdateServiceSpecificCredential" ], "Resource": "arn:aws:iam::*:user/${aws:username}" } ] }

Standard S3 Policy

January 28, 2020

Here’s a standard S3 policy to grant an IAM user access to a bucket within an AWS account. User is allowed to add, update, and delete objects. These 3 actions s3:ListAllMyBuckets, s3:GetBucketLocation, and s3:ListBucket are the additional permissions required to access the console. Also, the s3:PutObjectAcl and the s3:GetObjectAcl actions are required to be able to copy, cut, and paste objects within the console.

{
   "Version":"2012-10-17",
   "Statement":[
      {
         "Effect":"Allow",
         "Action":[
            "s3:ListAllMyBuckets"
         ],
         "Resource":"arn:aws:s3:::*"
      },
      {
         "Effect":"Allow",
         "Action":[
            "s3:ListBucket",
            "s3:GetBucketLocation"
         ],
         "Resource":"arn:aws:s3:::examplebucket"
      },
      {
         "Effect":"Allow",
         "Action":[
            "s3:PutObject",
            "s3:PutObjectAcl",
            "s3:GetObject",
            "s3:GetObjectAcl",
            "s3:DeleteObject"
         ],
         "Resource":"arn:aws:s3:::examplebucket/*"
      }
   ]
}

AWS CLI Add User

December 4, 2019

Here’s how to add an AWS user using the CLI.

aws iam create-user --user-name john.doe \
--tags Key='Name',Value='John Doe' Key='Role',Value='Admin'

Create an access key for the user.

aws iam create-access-key --user-name john.doe

SSH Access AllowGroups

September 16, 2019

If unable to login via SSH, check the /etc/ssh/sshd_config for AllowGroups.

AllowGroups root groupname

It’s case sensitive.

GCP Instance Scopes

March 15, 2019

Give Instances access to other cloud services using scopes.

gcloud alpha compute instances set-scopes instance-name \
--project project-name --zone us-central1-a \
--scopes=cloud-platform,cloud-source-repos,compute-rw,storage-rw