AWS IAM Policy - Force MFA - This policy allows users to manage their own passwords and MFA devices but nothing else unless they authenticate with MFA -- *EDIT*: I forgot where I found it in the 1st place. In fact this policy is explained statement by statement in AWS docs: https://docs.aws.amazon.com/IAM/latest/UserGuide/tutorial_users-self-man…

AWS IAM Policy - ForceMFA.json

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowAllUsersToListAccounts",
            "Effect": "Allow",
            "Action": [
                "iam:ListAccountAliases",
                "iam:ListUsers",
                "iam:GetAccountPasswordPolicy",
                "iam:GetAccountSummary"
            ],
            "Resource": "*"
        },
        {
            "Sid": "AllowIndividualUserToSeeAndManageOnlyTheirOwnAccountInformation",
            "Effect": "Allow",
            "Action": [
                "iam:CreateAccessKey",
                "iam:DeleteAccessKey",
                "iam:DeleteLoginProfile",
                "iam:GetLoginProfile",
                "iam:ListAccessKeys",
                "iam:UpdateAccessKey",
                "iam:UpdateLoginProfile",
                "iam:ListSigningCertificates",
                "iam:DeleteSigningCertificate",
                "iam:UpdateSigningCertificate",
                "iam:UploadSigningCertificate",
                "iam:ListSSHPublicKeys",
                "iam:GetSSHPublicKey",
                "iam:DeleteSSHPublicKey",
                "iam:UpdateSSHPublicKey",
                "iam:UploadSSHPublicKey"
            ],
            "Resource": "arn:aws:iam::*:user/${aws:username}"
        },
        {
            "Sid": "AllowIndividualUserToListOnlyTheirOwnMFA",
            "Effect": "Allow",
            "Action": [
                "iam:ListVirtualMFADevices",
                "iam:ListMFADevices"
            ],
            "Resource": [
                "arn:aws:iam::*:mfa/*",
                "arn:aws:iam::*:user/${aws:username}"
            ]
        },
        {
            "Sid": "AllowIndividualUserToManageTheirOwnMFA",
            "Effect": "Allow",
            "Action": [
                "iam:CreateVirtualMFADevice",
                "iam:DeleteVirtualMFADevice",
                "iam:EnableMFADevice",
                "iam:ResyncMFADevice"
            ],
            "Resource": [
                "arn:aws:iam::*:mfa/${aws:username}",
                "arn:aws:iam::*:user/${aws:username}"
            ]
        },
        {
            "Sid": "AllowIndividualUserToDeactivateOnlyTheirOwnMFAOnlyWhenUsingMFA",
            "Effect": "Allow",
            "Action": [
                "iam:DeactivateMFADevice"
            ],
            "Resource": [
                "arn:aws:iam::*:mfa/${aws:username}",
                "arn:aws:iam::*:user/${aws:username}"
            ],
            "Condition": {
                "Bool": {
                    "aws:MultiFactorAuthPresent": "true"
                }
            }
        },
        {
            "Sid": "BlockMostAccessUnlessSignedInWithMFA",
            "Effect": "Deny",
            "NotAction": [
                "iam:ChangePassword",
                "iam:CreateLoginProfile",
                "iam:CreateVirtualMFADevice",
                "iam:DeleteVirtualMFADevice",
                "iam:ListVirtualMFADevices",
                "iam:EnableMFADevice",
                "iam:ResyncMFADevice",
                "iam:ListAccountAliases",
                "iam:ListUsers",
                "iam:ListSSHPublicKeys",
                "iam:ListAccessKeys",
                "iam:ListServiceSpecificCredentials",
                "iam:ListMFADevices",
                "iam:GetAccountSummary",
                "sts:GetSessionToken"
            ],
            "Resource": "*",
            "Condition": {
                "BoolIfExists": {
                    "aws:MultiFactorAuthPresent": "false"
                }
            }
        }
    ]
}