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Merge pull request #463 from zfLQ2qx2/issue458
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Rewrite of check extra73
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@toniblyx
toniblyx committed Jan 27, 2020
2 parents ef001af + f735de8 commit f797805
Showing 1 changed file with 109 additions and 136 deletions.
245 changes: 109 additions & 136 deletions checks/check_extra73
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Original file line number Diff line number Diff line change
Expand Up @@ -19,46 +19,65 @@ CHECK_ALTERNATE_extra703="extra73"
CHECK_ALTERNATE_check73="extra73"
CHECK_ALTERNATE_check703="extra73"

# Improved and simplified check on Nov 18th 2018 due to a new bucket attribute
# called PolicyStatus, not available in all regions yet.

# extra73(){
# ALL_BUCKETS_LIST=$($AWSCLI s3api list-buckets --query 'Buckets[*].{Name:Name}' $PROFILE_OPT --region $REGION --output text)
# for bucket in $ALL_BUCKETS_LIST; do
# BUCKET_LOCATION=$($AWSCLI s3api get-bucket-location --bucket $bucket $PROFILE_OPT --region $REGION --output text 2>&1)
# if [[ $(echo "$BUCKET_LOCATION" | grep AccessDenied) ]]; then
# textFail "Access Denied Trying to Get Bucket Location for $bucket"
# continue
# fi
# if [[ "None" == $BUCKET_LOCATION ]]; then
# BUCKET_LOCATION="us-east-1"
# fi
# if [[ "EU" == $BUCKET_LOCATION ]]; then
# BUCKET_LOCATION="eu-west-1"
# fi
# Verified with AWS support that if get-bucket-acl doesn't return a grant
# for All and get-bucket-policy-status returns IsPublic false or bad request
# (no policy) then the bucket can be considered not public - though
# individual objects may still be. If in addition put-public-access-block is
# used to set IgnorePublicAcls and RestrictPublicBuckets to true then that
# causes Amazon S3 to ignore all public ACLs on a bucket and any objects that
# it contains.
#
# BUCKET_POLICY_STATUS=$($AWSCLI s3api get-bucket-policy-status --bucket $bucket --query PolicyStatus.IsPublic --output text | grep False)
# if [[ $BUCKET_POLICY_STATUS ]];then
# textFail "$BUCKET_LOCATION: $bucket bucket is Public!" "$BUCKET_LOCATION"
# else
# textPass "$BUCKET_LOCATION: $bucket bucket is not Public" "$BUCKET_LOCATION"
# fi
# done
# }

# This check does not address legacy ACLs or policies that would give
# public access if not blocked at account or bucket level, instead it tries
# to reward the use of more broadly restrictive controls with quicker and less
# computational intensive checks.
#
# If we are assembling an inventory then maybe that is not what we want but
# for day to day usage that is probably desirable.

extra73(){
textInfo "Looking for open S3 Buckets (ACLs and Policies) in all regions... "
ALL_BUCKETS_LIST=$($AWSCLI s3api list-buckets --query 'Buckets[*].{Name:Name}' $PROFILE_OPT --output text)

for bucket in $ALL_BUCKETS_LIST; do
#
# If public ACLs disabled at account level then look no further
#
ACCOUNT_PUBLIC_ACCESS_BLOCK=$($AWSCLI s3control get-public-access-block $PROFILE_OPT --region $REGION --account-id $ACCOUNT_NUM --output json 2>&1)
if [[ $(echo "$ACCOUNT_PUBLIC_ACCESS_BLOCK" | grep AccessDenied) ]]; then
textFail "Access Denied Trying to Get Public Access Block for $bucket"
return
fi
if [[ $(echo "$ACCOUNT_PUBLIC_ACCESS_BLOCK" | grep NoSuchPublicAccessBlockConfiguration) ]]; then
ACCOUNTIGNOREPUBLICACLS=""
ACCOUNTRESTRICTPUBLICBUCKETS=""
else
ACCOUNTIGNOREPUBLICACLS=$(echo "$ACCOUNT_PUBLIC_ACCESS_BLOCK" | jq -r '.PublicAccessBlockConfiguration.IgnorePublicAcls')
ACCOUNTRESTRICTPUBLICBUCKETS=$(echo "$ACCOUNT_PUBLIC_ACCESS_BLOCK" | jq -r '.PublicAccessBlockConfiguration.RestrictPublicBuckets')
fi
if [[ $ACCOUNTIGNOREPUBLICACLS == "true" && $ACCOUNTRESTRICTPUBLICBUCKETS == "true" ]]; then
textPass "All S3 public access blocked at account level"
return
fi

# 3 Different problems, let's show only 1 finding all together
S3_FINDING_ALLUSERS_ACL="Ok"
S3_FINDING_AUTHUSERS_ACL="Ok"
S3_FINDING_POLICY="Ok"
#
# Otherwise start to iterate bucket
#
ALL_BUCKETS_LIST=$($AWSCLI s3api list-buckets --query 'Buckets[*].{Name:Name}' $PROFILE_OPT --output text 2>&1)
if [[ $(echo "$ALL_BUCKETS_LIST" | grep AccessDenied) ]]; then
textFail "Access Denied Trying to List Buckets"
return
fi
if [[ "$ALL_BUCKETS_LIST" == "" ]]; then
textInfo "No buckets found"
return
fi

# LOCATION
for bucket in $ALL_BUCKETS_LIST; do

#
# LOCATION - requests referencing buckets created after March 20, 2019
# must be made to S3 endpoints in the same region as the bucket was
# created.
#
BUCKET_LOCATION=$($AWSCLI s3api get-bucket-location --bucket $bucket $PROFILE_OPT --output text 2>&1)
if [[ $(echo "$BUCKET_LOCATION" | grep AccessDenied) ]]; then
textFail "Access Denied Trying to Get Bucket Location for $bucket"
Expand All @@ -71,111 +90,65 @@ extra73(){
BUCKET_LOCATION="eu-west-1"
fi

# EXPLICIT DENY
CHEK_FOR_EXPLICIT_DENY=$($AWSCLI s3api get-bucket-acl $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --output text 2>&1)
if [[ $(echo "$CHEK_FOR_EXPLICIT_DENY" | grep AccessDenied) ]] ; then
textInfo "$BUCKET_LOCATION: $bucket have an explicit Deny. Not possible to get ACL." "$bucket" "$BUCKET_LOCATION"
#
# If public ACLs disabled at bucket level then look no further
#
BUCKET_PUBLIC_ACCESS_BLOCK=$($AWSCLI s3api get-public-access-block $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --output json 2>&1)
if [[ $(echo "$BUCKET_PUBLIC_ACCESS_BLOCK" | grep AccessDenied) ]]; then
textFail "Access Denied Trying to Get Public Access Block for $bucket"
continue
fi
if [[ $(echo "$BUCKET_PUBLIC_ACCESS_BLOCK" | grep NoSuchPublicAccessBlockConfiguration) ]]; then
BUCKETIGNOREPUBLICACLS=""
BUCKETRESTRICTPUBLICBUCKETS=""
else
# PUBLIC BLOCK
# https://docs.aws.amazon.com/cli/latest/reference/s3api/get-public-access-block.html
BUCKET_PUBLIC_BLOCK=$($AWSCLI s3api get-public-access-block --bucket $bucket $PROFILE_OPT --region $BUCKET_LOCATION 2>/dev/null)
BUCKET_PUBLIC_BLOCK_IGNOREPUBLICACL=$(echo $BUCKET_PUBLIC_BLOCK | jq .PublicAccessBlockConfiguration.BlockPublicAcls 2>/dev/null)
BUCKET_PUBLIC_BLOCK_BLOCKPUBLICPOLICY=$(echo $BUCKET_PUBLIC_BLOCK | jq .PublicAccessBlockConfiguration.BlockPublicPolicy 2>/dev/null)
BUCKET_PUBLIC_BLOCK_BLOCKPUBLICACLS=$(echo $BUCKET_PUBLIC_BLOCK | jq .PublicAccessBlockConfiguration.BlockPublicAcls 2>/dev/null)
BUCKET_PUBLIC_BLOCK_RESTRICPUBLICBUCKET=$(echo $BUCKET_PUBLIC_BLOCK | jq .PublicAccessBlockConfiguration.RestrictPublicBuckets 2>/dev/null)
if [[ $BUCKET_PUBLIC_BLOCK_IGNOREPUBLICACL == "true" ]] && [[ $BUCKET_PUBLIC_BLOCK_BLOCKPUBLICPOLICY == "true" ]] && [[ $BUCKET_PUBLIC_BLOCK_BLOCKPUBLICACLS == "true" ]] && [[ $BUCKET_PUBLIC_BLOCK_RESTRICPUBLICBUCKET == "true" ]]; then
textPass "$BUCKET_LOCATION: $bucket bucket is public blocked (public-access-block)" "$BUCKET_LOCATION"
else
## ACL
# check if AllUsers is in the ACL as Grantee
CHECK_BUCKET_ALLUSERS_ACL=$($AWSCLI s3api get-bucket-acl $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AllUsers']" --output text |grep -v GRANTEE)
CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_ALLUSERS_ACL)
# check if AuthenticatedUsers is in the ACL as Grantee, they will have access with sigened URL only
CHECK_BUCKET_AUTHUSERS_ACL=$($AWSCLI s3api get-bucket-acl $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AuthenticatedUsers']" --output text |grep -v GRANTEE)
CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_AUTHUSERS_ACL)
## POLICY
BUCKET_POLICY_STATUS=$($AWSCLI s3api get-bucket-policy-status $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --query PolicyStatus.IsPublic --output text 2>/dev/null)
if [[ $CHECK_BUCKET_ALLUSERS_ACL || $CHECK_BUCKET_AUTHUSERS_ACL || $CHECK_BUCKET_ALLUSERS_POLICY == "True" ]]; then
if [[ $CHECK_BUCKET_ALLUSERS_ACL || $CHECK_BUCKET_AUTHUSERS_ACL ]] && [[ $BUCKET_PUBLIC_BLOCK_IGNOREPUBLICACL != "true" ]];then
if [[ $CHECK_BUCKET_ALLUSERS_ACL ]];then
S3_FINDING_ALLUSERS_ACL="bucket ACL is open to the Internet (Everyone) with permissions: $CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE"
fi
if [[ $CHECK_BUCKET_AUTHUSERS_ACL ]];then
S3_FINDING_AUTHUSERS_ACL="bucket ACL is open to Authenticated users (Any AWS user) with permissions: $CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE"
fi
fi
if [[ $BUCKET_PUBLIC_BLOCK_RESTRICPUBLICBUCKET != "true" ]] && [[ $BUCKET_POLICY_STATUS == "True" ]]; then
# Here comes the magic: Find Statement Allow, Principal * and No Condition
BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION=$($AWSCLI s3api get-bucket-policy $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket \
| jq '.Policy | fromjson' | jq '.Statement[] | select(.Effect=="Allow") | select(.Principal=="*" or .Principal.AWS=="*" or .Principal.CanonicalUser=="*") | select(has("Condition") | not)')
if [[ $BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION ]]; then
# Let's do more magic and identify who can do what
BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION_DETAILS=$(echo $BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION \
| jq '"[Principal: " + (.Principal|tostring) + " Action: " + (.Action|tostring) + "]"' )
S3_FINDING_POLICY="bucket policy allow perform actions: $BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION_DETAILS"
else
textPass "$BUCKET_LOCATION: $bucket bucket policy with conditions" "$BUCKET_LOCATION"
fi
fi
else
textPass "$BUCKET_LOCATION: $bucket bucket is not open" "$bucket" "$BUCKET_LOCATION"
fi
fi
BUCKETIGNOREPUBLICACLS=$(echo "$BUCKET_PUBLIC_ACCESS_BLOCK" | jq -r '.PublicAccessBlockConfiguration.IgnorePublicAcls')
BUCKETRESTRICTPUBLICBUCKETS=$(echo "$BUCKET_PUBLIC_ACCESS_BLOCK" | jq -r '.PublicAccessBlockConfiguration.RestrictPublicBuckets')
fi
if [[ $S3_FINDING_ALLUSERS_ACL != "Ok" ]] || [[ $S3_FINDING_AUTHUSERS_ACL != "Ok" ]] || [[ $S3_FINDING_POLICY != "Ok" ]] ; then
textFail "$BUCKET_LOCATION: (bucket: $bucket) ALLUSERS_ACL: $S3_FINDING_ALLUSERS_ACL | AUTHUSERS_ACL: $S3_FINDING_AUTHUSERS_ACL | BUCKET_POLICY: $S3_FINDING_POLICY" "$BUCKET_LOCATION"
if [[ $BUCKETIGNOREPUBLICACLS == "true" && $BUCKETRESTRICTPUBLICBUCKETS == "true" ]]; then
textPass "$BUCKET_LOCATION: $bucket bucket is not Public" "$BUCKET_LOCATION"
continue
fi

#
# Check for public ACL grants
#
BUCKET_ACL=$($AWSCLI s3api get-bucket-acl $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --output json 2>&1)
if [[ $(echo "$BUCKET_ACL" | grep AccessDenied) ]]; then
textFail "Access Denied Trying to Get Bucket Acl for $bucket"
continue
fi

ALLUSERS_ACL=$(echo "$BUCKET_ACL" | jq '.Grants[]|select(.Grantee.URI != null)|select(.Grantee.URI | endswith("/AllUsers"))')
if [[ $ALLUSERS_ACL != "" ]]; then
textFail "$BUCKET_LOCATION: $bucket bucket is Public!" "$BUCKET_LOCATION"
continue
fi

AUTHENTICATEDUSERS_ACL=$(echo "$BUCKET_ACL" | jq '.Grants[]|select(.Grantee.URI != null)|select(.Grantee.URI | endswith("/AuthenticatedUsers"))')
if [[ $AUTHENTICATEDUSERS_ACL != "" ]]; then
textFail "$BUCKET_LOCATION: $bucket bucket is Public!" "$BUCKET_LOCATION"
continue
fi

#
# Check for public access in policy
#
BUCKET_POLICY_STATUS=$($AWSCLI s3api get-bucket-policy-status $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --query PolicyStatus.IsPublic --output text 2>&1)
if [[ $(echo "$BUCKET_POLICY_STATUS" | grep AccessDenied) ]]; then
textFail "Access Denied Trying to Get Bucket Policy Status for $bucket"
continue
fi
if [[ $(echo "$BUCKET_POLICY_STATUS" | grep NoSuchBucketPolicy) ]]; then
BUCKET_POLICY_STATUS="False"
fi

if [[ $BUCKET_POLICY_STATUS != "" && $BUCKET_POLICY_STATUS != "False" ]]; then
textFail "$BUCKET_LOCATION: $bucket bucket is Public!" "$BUCKET_LOCATION"
continue
fi

textPass "$BUCKET_LOCATION: $bucket bucket is not Public" "$BUCKET_LOCATION"

done
}

# Then implementation below makes pararel checks but can reach AWS API limits
# and eventually doesn't work as expected

# extra73(){
# textTitle "$ID73" "$TITLE73" "NOT_SCORED" "EXTRA"
# textNotice "Looking for open S3 Buckets (ACLs and Policies) in all regions... "
# ALL_BUCKETS_LIST=$($AWSCLI s3api list-buckets --query 'Buckets[*].{Name:Name}' --profile $PROFILE --region $REGION --output text)
# for bucket in $ALL_BUCKETS_LIST; do
# extra73Thread $bucket &
# done
# wait
# }
# extra73Thread(){
# bucket=$1
# BUCKET_LOCATION=$($AWSCLI s3api get-bucket-location --bucket $bucket --profile $PROFILE --region $REGION --output text 2>&1)
# if [[ $(echo "$BUCKET_LOCATION" | grep AccessDenied) ]]; then
# textFail "Access Denied Trying to Get Bucket Location for $bucket"
# return
# fi
# if [[ "None" == $BUCKET_LOCATION ]]; then
# BUCKET_LOCATION="us-east-1"
# fi
# if [[ "EU" == $BUCKET_LOCATION ]]; then
# BUCKET_LOCATION="eu-west-1"
# fi
# # check if AllUsers is in the ACL as Grantee
# CHECK_BUCKET_ALLUSERS_ACL=$($AWSCLI s3api get-bucket-acl --profile $PROFILE --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AllUsers']" --output text |grep -v GRANTEE)
# CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_ALLUSERS_ACL)
# # check if AuthenticatedUsers is in the ACL as Grantee, they will have access with sigened URL only
# CHECK_BUCKET_AUTHUSERS_ACL=$($AWSCLI s3api get-bucket-acl --profile $PROFILE --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AuthenticatedUsers']" --output text |grep -v GRANTEE)
# CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_AUTHUSERS_ACL)
# # to prevent error NoSuchBucketPolicy first clean the output controlling stderr
# TEMP_POLICY_FILE=$(mktemp -t prowler-${ACCOUNT_NUM}-${bucket}.policy.XXXXXXXXXX)
# $AWSCLI s3api get-bucket-policy --profile $PROFILE --region $BUCKET_LOCATION --bucket $bucket --output text --query Policy > $TEMP_POLICY_FILE 2> /dev/null
# # check if the S3 policy has Principal as *
# CHECK_BUCKET_ALLUSERS_POLICY=$(cat $TEMP_POLICY_FILE | sed -e 's/[{}]/''/g' | awk -v k="text" '{n=split($0,a,","); for (i=1; i<=n; i++) print a[i]}'|awk '/Principal/ && !skip { print } { skip = /Deny/} '|grep ^\"Principal|grep \*)
# if [[ $CHECK_BUCKET_ALLUSERS_ACL || $CHECK_BUCKET_AUTHUSERS_ACL || $CHECK_BUCKET_ALLUSERS_POLICY ]];then
# if [[ $CHECK_BUCKET_ALLUSERS_ACL ]];then
# textWarn "$BUCKET_LOCATION: $bucket bucket is open to the Internet (Everyone) with permissions: $CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE" "$BUCKET_LOCATION"
# fi
# if [[ $CHECK_BUCKET_AUTHUSERS_ACL ]];then
# textWarn "$BUCKET_LOCATION: $bucket bucket is open to Authenticated users (Any AWS user) with permissions: $CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE" "$BUCKET_LOCATION"
# fi
# if [[ $CHECK_BUCKET_ALLUSERS_POLICY ]];then
# textWarn "$BUCKET_LOCATION: $bucket bucket policy \"may\" allow Anonymous users to perform actions (Principal: \"*\")" "$BUCKET_LOCATION"
# fi
# else
# textOK "$BUCKET_LOCATION: $bucket bucket is not open" "$BUCKET_LOCATION"
# fi
# rm -f $TEMP_POLICY_FILE
# }

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