diff --git a/phpseclib/Net/SSH1.php b/phpseclib/Net/SSH1.php
index 8d8a9945..f1fae02b 100644
--- a/phpseclib/Net/SSH1.php
+++ b/phpseclib/Net/SSH1.php
@@ -1128,6 +1128,7 @@ class Net_SSH1
 
         $padding_length = 8 - ($temp['length'] & 7);
         $length = $temp['length'] + $padding_length;
+        $raw = '';
 
         while ($length > 0) {
             $temp = fread($this->fsock, $length);