@(#)Mordred Labs advisory - Integer overflow in PHP str_repeat() function

From: Sir Mordred (mordred@s-mail.com)
Date: Tue Apr 01 2003 - 04:29:57 PST

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    //@(#) Mordred Security Labs advisory 
    
    Release date: April 1, 2003 
    Name: Integer overflow in PHP str_repeat() function
    Versions affected: all versions 
    Risk: average
    Author: Sir Mordred (mordred@s-mail.com) 
    
    I. Description: 
    
    PHP is a widely-used general-purpose scripting language that is
    especially suited for Web development and can be embedded into HTML.
    Please visit http://www.php.net for more information about PHP.
    
    II. Details: 
    
    The function str_repeat(string input, int multiplier) returns input
    repeated multiplier times.
    
    The implementation of this function suffers from a simple integer overflow
    caused by 
    a very long second argument and could allow a local/remote attacker in the
    worst case to gain control over the web server.
    
    The following short script will illustrate this vulnerability:
    
    $ cat t.php
    <?php 
        str_repeat(str_repeat("A", 0x2000), 0x40000000);
    ?>
    
    III. Platforms tested
    
    Linux 2.4 with Apache 1.3.27 / PHP 4.3.1
    
    IV. Vendor response
    
    Vendor has been contacted.
    
    
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