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prowler/checks/check_extra771

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#!/usr/bin/env bash
# Prowler - the handy cloud security tool (copyright 2018) 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_extra771="7.71"
CHECK_TITLE_extra771="[extra771] Check if S3 buckets have policies which allow WRITE access "
CHECK_SCORED_extra771="NOT_SCORED"
CHECK_CIS_LEVEL_extra771="EXTRA"
CHECK_SEVERITY_extra771="Critical"
CHECK_ASFF_RESOURCE_TYPE_extra771="AwsS3Bucket"
CHECK_ALTERNATE_check771="extra771"
CHECK_SERVICENAME_extra771="s3"
CHECK_RISK_extra771='Non intended users can put objects in a given bucket.'
CHECK_REMEDIATION_extra771='Ensure proper bucket policy is in place with the least privilege principle applied.'
CHECK_DOC_extra771='https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_s3_rw-bucket.html'
CHECK_CAF_EPIC_extra771='IAM'
extra771(){
LIST_OF_BUCKETS=$("${AWSCLI}" s3api list-buckets ${PROFILE_OPT} --region "${REGION}" --query "sort_by(Buckets, &Name)[].Name" --output text 2>&1)
if grep -q -E 'AccessDenied|UnauthorizedOperation|AuthorizationError' <<< "${LIST_OF_BUCKETS}"; then
textInfo "${REGION}: Access Denied trying to list buckets" "${REGION}"
return
fi
if [[ "${LIST_OF_BUCKETS}" ]]; then
for bucket in ${LIST_OF_BUCKETS};do
# Recover Bucket region
BUCKET_REGION=$("${AWSCLI}" ${PROFILE_OPT} s3api get-bucket-location --bucket "${bucket}" --query LocationConstraint --output text)
if grep -q -E 'AccessDenied|UnauthorizedOperation|AuthorizationError' <<< "${BUCKET_POLICY_STATEMENTS}"; then
textInfo "${REGION}: Access Denied trying to get bucket policy for ${bucket}" "${REGION}"
fi
# If None use default region
if [[ "${BUCKET_REGION}" == "None" ]]; then
BUCKET_REGION="${REGION}"
fi
# Recover Bucket policy statements
BUCKET_POLICY_STATEMENTS=$("${AWSCLI}" s3api ${PROFILE_OPT} get-bucket-policy --region "${BUCKET_REGION}" --bucket "${bucket}" --output json --query Policy 2>&1)
if grep -q -E 'AccessDenied|UnauthorizedOperation|AuthorizationError' <<< "${BUCKET_POLICY_STATEMENTS}"; then
textInfo "${REGION}: Access Denied trying to get bucket policy for ${bucket}" "${REGION}"
continue
fi
if grep -q -E 'NoSuchBucketPolicy'<<< "${BUCKET_POLICY_STATEMENTS}"; then
textInfo "${REGION}: Bucket policy does not exist for bucket ${bucket}" "${REGION}"
else
BUCKET_POLICY_BAD_STATEMENTS=$(jq --compact-output --arg arn "arn:${AWS_PARTITION}:s3:::$bucket" 'fromjson | .Statement[]|select(
.Effect=="Allow" and
(
( (.Principal|type == "object") and (.Principal.AWS == "*") ) or
( (.Principal|type == "string") and (.Principal == "*") )
) and
(
( (.Action|type == "string") and (.Action|startswith("s3:Put")) ) or
( (.Action|type == "string") and (.Action|startswith("s3:*")) ) or
( (.Action|type == "array") and (.Action[]|startswith("s3:Put")) ) or
( (.Action|type == "array") and (.Action[]|startswith("s3:*")) )
) and
.Condition == null
)' <<< "${BUCKET_POLICY_STATEMENTS}" | tr '\n' ' ')
# Make sure JSON comma characted will not break CSV output. Replace "," by word "[comma]"
BUCKET_POLICY_BAD_STATEMENTS="${BUCKET_POLICY_BAD_STATEMENTS//,/[comma]}"
if [[ "${BUCKET_POLICY_BAD_STATEMENTS}" != "" ]]; then
textFail "${REGION}: Bucket ${bucket} allows public write: ${BUCKET_POLICY_BAD_STATEMENTS}" "${REGION}" "${bucket}"
else
textPass "${REGION}: Bucket ${bucket} has S3 bucket policy which does not allow public write access" "${REGION}" "${bucket}"
fi
fi
done
else
textInfo "${REGION}: No S3 Buckets found" "${REGION}"
fi
}