#!/usr/bin/env bash

# Prowler - the handy cloud security tool (copyright 2019) by Toni de la Fuente
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may not
# use this file except in compliance with the License. You may obtain a copy
# of the License at http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software distributed
# under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
# CONDITIONS OF ANY KIND, either express or implied. See the License for the
# specific language governing permissions and limitations under the License.
CHECK_ID_extra741="7.41"
CHECK_TITLE_extra741="[extra741] Find secrets in EC2 User Data"
CHECK_SCORED_extra741="NOT_SCORED"
CHECK_TYPE_extra741="EXTRA"
CHECK_SEVERITY_extra741="Critical"
CHECK_ASFF_RESOURCE_TYPE_extra741="AwsEc2Instance"
CHECK_ALTERNATE_check741="extra741"
CHECK_SERVICENAME_extra741="ec2"
CHECK_RISK_extra741='Secrets hardcoded into instance user data can be used by malware and bad actors to gain lateral access to other services.'
CHECK_REMEDIATION_extra741='Implement automated detective control (e.g. using tools like Prowler ) to scan accounts for passwords and secrets. Use secrets manager service to store and retrieve passwords and secrets. '
CHECK_DOC_extra741='https://docs.aws.amazon.com/secretsmanager/latest/userguide/tutorials_basic.html'
CHECK_CAF_EPIC_extra741='IAM'

extra741(){
  SECRETS_TEMP_FOLDER="$PROWLER_DIR/secrets-$ACCOUNT_NUM"
  if [[ ! -d $SECRETS_TEMP_FOLDER ]]; then
    # this folder is deleted once this check is finished
    mkdir $SECRETS_TEMP_FOLDER
  fi

  for regx in $REGIONS; do
    LIST_OF_EC2_INSTANCES=$($AWSCLI ec2 describe-instances $PROFILE_OPT --region $regx --query Reservations[*].Instances[*].InstanceId --output text --max-items $MAXITEMS | grep -v None)
    if [[ $LIST_OF_EC2_INSTANCES ]];then
      for instance in $LIST_OF_EC2_INSTANCES; do
        EC2_USERDATA_FILE="$SECRETS_TEMP_FOLDER/extra741-$instance-userData.decoded"
        EC2_USERDATA=$($AWSCLI ec2 describe-instance-attribute --attribute userData $PROFILE_OPT --region $regx --instance-id $instance --query UserData.Value --output text| grep -v ^None | decode_report > $EC2_USERDATA_FILE)
        if [ -s "$EC2_USERDATA_FILE" ];then
          # This finds ftp or http URLs with credentials and common keywords
          # FINDINGS=$(egrep -i '[[:alpha:]]*://[[:alnum:]]*:[[:alnum:]]*@.*/|key|secret|token|pass' $EC2_USERDATA_FILE |wc -l|tr -d '\ ')
          # New implementation using https://github.com/Yelp/detect-secrets
          # Test if user data is a valid GZIP file, if so gunzip first
          if gunzip -t "$EC2_USERDATA_FILE" > /dev/null 2>&1; then
            mv "$EC2_USERDATA_FILE" "$EC2_USERDATA_FILE.gz" ; gunzip "$EC2_USERDATA_FILE.gz"
          fi
          FINDINGS=$(secretsDetector file "$EC2_USERDATA_FILE")
          if [[ $FINDINGS -eq 0 ]]; then
            textPass "$regx: No secrets found in $instance User Data" "$regx" "$instance"
            # delete file if nothing interesting is there
            rm -f "$EC2_USERDATA_FILE"
          else
            textFail "$regx: Potential secret found in $instance User Data" "$regx" "$instance"
            # delete file to not leave trace, user must look at the instance User Data
            rm -f "$EC2_USERDATA_FILE"
          fi
        else
          textPass "$regx: No secrets found in $instance User Data or it is empty" "$regx" "$instance"
        fi
      done
    else
      textInfo "$regx: No EC2 instances found" "$regx"
    fi
  done
  rm -rf $SECRETS_TEMP_FOLDER
}