diff --git a/src/settings.js b/src/settings.js
index a15ccbea6..789f9abea 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -395,6 +395,8 @@ function setBackupConfig(backupConfig, callback) {
     } else if (backupConfig.provider === 's3') {
         if (typeof backupConfig.accessKeyId !== 'string') return callback(new SettingsError(SettingsError.BAD_FIELD, 'accessKeyId must be a string'));
         if (typeof backupConfig.secretAccessKey !== 'string') return callback(new SettingsError(SettingsError.BAD_FIELD, 'secretAccessKey must be a string'));
+        if (typeof backupConfig.bucket !== 'string') return callback(new SettingsError(SettingsError.BAD_FIELD, 'bucket must be a string'));
+        if (typeof backupConfig.prefix !== 'string') return callback(new SettingsError(SettingsError.BAD_FIELD, 'prefix must be a string'));
     }
 
     settingsdb.set(exports.BACKUP_CONFIG_KEY, JSON.stringify(backupConfig), function (error) {