prowler/checks/check23

#!/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_check23="2.3"
CHECK_TITLE_check23="[check23] Ensure the S3 bucket CloudTrail logs to is not publicly accessible"
CHECK_SCORED_check23="SCORED"
CHECK_CIS_LEVEL_check23="LEVEL1"
CHECK_SEVERITY_check23="Critical"
CHECK_ASFF_TYPE_check23="Software and Configuration Checks/Industry and Regulatory Standards/CIS AWS Foundations Benchmark"
CHECK_ASFF_RESOURCE_TYPE_check23="AwsS3Bucket"
CHECK_ALTERNATE_check203="check23"
CHECK_ASFF_COMPLIANCE_TYPE_check23="ens-op.exp.10.aws.trail.3 ens-op.exp.10.aws.trail.4"
CHECK_SERVICENAME_check23="cloudtrail"
CHECK_RISK_check23='Allowing public access to CloudTrail log content may aid an adversary in identifying weaknesses in the affected accounts use or configuration.'
CHECK_REMEDIATION_check23='Analyze Bucket policy to validate appropriate permissions. Ensure the AllUsers principal is not granted privileges. Ensure the AuthenticatedUsers principal is not granted privileges.'
CHECK_DOC_check23='https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_principal.html'
CHECK_CAF_EPIC_check23='Logging and Monitoring'

check23(){
  for regx in $REGIONS
  do
    TRAILS_DETAILS=$($AWSCLI cloudtrail describe-trails $PROFILE_OPT --region $regx --query 'trailList[*].{Name:Name, HomeRegion:HomeRegion, Multiregion:IsMultiRegionTrail, BucketName:S3BucketName}' --output text 2>&1)
    if [[ $(echo "$TRAILS_DETAILS" | grep AccessDenied) ]]; then
      textInfo "$regx: Access Denied trying to describe trails" "$regx"
      continue
    fi
    if [[ $TRAILS_DETAILS ]]
    then
      for REGION_TRAIL in "${TRAILS_DETAILS}"
      do
        while read -r TRAIL_BUCKET TRAIL_HOME_REGION IS_MULTIREGION TRAIL_NAME
        do
          if [[ ! "${TRAIL_BUCKET}" ]]
          then
            if [[ "${IS_MULTIREGION}" == "True" ]]
              then
                textFail "$regx: Multiregion trail ${TRAIL_NAME} configured from region ${TRAIL_HOME_REGION}  does not publish to S3" "$regx" "$TRAIL_NAME"
              else
                textFail "$regx: Single region trail ${TRAIL_NAME}  does not publish to S3" "$regx" "$TRAIL_NAME"
              fi
            continue
          fi

          BUCKET_LOCATION=$($AWSCLI s3api get-bucket-location $PROFILE_OPT --region $regx --bucket $TRAIL_BUCKET --output text 2>&1)
          if [[ $(echo "$BUCKET_LOCATION" | grep AccessDenied) ]]
          then
            textInfo "$regx: Trail ${TRAIL_NAME} with home region ${TRAIL_HOME_REGION} Access Denied getting bucket location for bucket $TRAIL_BUCKET" "$regx" "$TRAIL_NAME"
            continue
          fi
          if [[ $(echo "$BUCKET_LOCATION" | grep NoSuchBucket) ]]
          then
            textInfo "$regx: Trail ${TRAIL_NAME} with home region ${TRAIL_HOME_REGION} S3 logging bucket $TRAIL_BUCKET does not exist" "$regx" "$TRAIL_NAME"
            continue
          fi
          if [[ $BUCKET_LOCATION == "None" ]]; then
              BUCKET_LOCATION="us-east-1"
          fi
          if [[ $BUCKET_LOCATION == "EU" ]]; then
            BUCKET_LOCATION="eu-west-1"
          fi

          CLOUDTRAILBUCKET_HASALLPERMISIONS=$($AWSCLI s3api get-bucket-acl --bucket $TRAIL_BUCKET $PROFILE_OPT --region $BUCKET_LOCATION --query 'Grants[?Grantee.URI==`http://acs.amazonaws.com/groups/global/AllUsers`]' --output text 2>&1)
          if [[ $(echo "$CLOUDTRAILBUCKET_HASALLPERMISIONS" | grep AccessDenied) ]]; then
            textInfo "$regx: Trail ${TRAIL_NAME} with home region ${TRAIL_HOME_REGION} Access Denied getting bucket acl for bucket $TRAIL_BUCKET" "$regx" "$TRAIL_NAME"
            continue
          fi

          if [[ ! $CLOUDTRAILBUCKET_HASALLPERMISIONS ]]; then
            textPass "$regx: Trail ${TRAIL_NAME} with home region ${TRAIL_HOME_REGION} S3 logging bucket $TRAIL_BUCKET is not publicly accessible" "$regx" "$TRAIL_NAME"
          else
            textFail "$regx: Trail ${TRAIL_NAME} with home region ${TRAIL_HOME_REGION} S3 logging bucket $TRAIL_BUCKET is publicly accessible" "$regx" "$TRAIL_NAME"
          fi

        done <<< "${REGION_TRAIL}"
      done
    else
      textPass "$regx: No trails found in the region" "$regx"
    fi

  done

}