diff --git a/README.md b/README.md
index 2b540e3..6c28526 100755
--- a/README.md
+++ b/README.md
@@ -15,13 +15,14 @@ Run and Eventarc.
 
 ## Changes
 
-*   2019-09-01 Initial version
-*   2020-10-05 Fixes for ClamAV OOM
-*   2021-10-14 Use Cloud Run and EventArc instead of Cloud Functions/App Engine
-*   2021-10-22 Improve resiliency, Use streaming reads (no temp disk required),
+* 2019-09-01 Initial version
+* 2020-10-05 Fixes for ClamAV OOM
+* 2021-10-14 Use Cloud Run and EventArc instead of Cloud Functions/App Engine
+* 2021-10-22 Improve resiliency, Use streaming reads (no temp disk required),
     improve logging, and handles files in subdirectories
-*   2021-11-08 Add support for scanning multiple buckets, improve error
-    handling to prevent infinite retries,
+* 2021-11-08 Add support for scanning multiple buckets, improve error
+    handling to prevent infinite retries
+* 2021-11-22 Remove requirement for Project Viewer permissions.
 
 ## License
 
diff --git a/cloudrun-malware-scanner/package.json b/cloudrun-malware-scanner/package.json
index 7f82606..130d040 100644
--- a/cloudrun-malware-scanner/package.json
+++ b/cloudrun-malware-scanner/package.json
@@ -1,6 +1,6 @@
 {
   "name": "gcs-malware-scanner",
-  "version": "1.2.0",
+  "version": "1.3.0",
   "description": "Service to scan GCS documents for the malware and move the analyzed documents to appropriate buckets",
   "main": "index.js",
   "scripts": {
diff --git a/cloudrun-malware-scanner/server.js b/cloudrun-malware-scanner/server.js
index 3f40e7d..5b5dd5c 100644
--- a/cloudrun-malware-scanner/server.js
+++ b/cloudrun-malware-scanner/server.js
@@ -32,7 +32,7 @@ const MAX_FILE_SIZE = 5000000000; // 5GiB
  * Configuration object.
  *
  * Values are read from the environment variable CONFIG_FILE (which specifies a
- * JSON file to read the config from) or single-bucket config variables: 
+ * JSON file to read the config from) or single-bucket config variables:
  * UNSCANNED_BUCKET, CLEAN_BUCKET and QUARANTINED_BUCKET.
  * See {@link readAndVerifyConfig}.
  *
@@ -273,24 +273,40 @@ async function readAndVerifyConfig() {
     throw new Error('No buckets configured');
   }
 
-  logger.info("BUCKET_CONFIG: "+JSON.stringify(BUCKET_CONFIG, null, 2));
+  logger.info('BUCKET_CONFIG: '+JSON.stringify(BUCKET_CONFIG, null, 2));
 
   // Check buckets are specified and exist.
   let success = true;
   for (let x = 0; x < BUCKET_CONFIG.buckets.length; x++) {
-    for (const bucket of ['unscanned', 'clean', 'quarantined']) {
-      if (!BUCKET_CONFIG.buckets[x][bucket]) {
-        logger.fatal(
-            `Error in bucket config #${x}: no "${bucket}" bucket defined`);
+    const config = BUCKET_CONFIG.buckets[x];
+    for (const bucketType of ['unscanned', 'clean', 'quarantined']) {
+      const bucketName = config[bucketType];
+      if (!bucketName) {
+        logger.fatal(`Error in bucket config[${x}]: no "${
+          bucketType}" bucket defined`);
         success = false;
       }
-      // Check for bucket existence
-      if (!(await storage.bucket(BUCKET_CONFIG.buckets[x][bucket]).exists())) {
-        logger.fatal(`Error in bucket config[${x}]: "${bucket}" bucket: ${
-          BUCKET_CONFIG.buckets[x][bucket]} does not exist`);
+      // Check for bucket existence by listing files in bucket, will throw
+      // an exception if the bucket is not readable.
+      // This is used in place of Bucket.exists() to avoid the need for
+      // Project/viewer permission.
+      try {
+        await storage.bucket(bucketName).getFiles(
+            {maxResults: 1, prefix: 'zzz', autoPaginate: false});
+      } catch (e) {
+        logger.fatal(`Error in bucket config[${x}]: cannot view files in "${
+          bucketType}" bucket: ${bucketName} : ${e.message}`);
+        logger.debug({err: e});
         success = false;
       }
     }
+    if(config.unscanned === config.clean
+        || config.unscanned === config.quarantined
+        || config.clean === config.quarantined) {
+      logger.fatal(
+          `Error in bucket config[${x}]: bucket names are not unique`);
+      success = false;
+    }
   }
   if (!success) {
     throw new Error('Invalid configuration');