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Home » Hacking News » CLA-2002:545-Conectiva Linux Security Announcement - php4

CLA-2002:545-Conectiva Linux Security Announcement - php4

by Nikola Strahija on November 14th, 2002 PHP[1] is a very popular scripting language used by web servers to offer dynamic content.

This update addresses the following issues:

1) Safe mode bypass vulnerability[3]
Wojciech Purczynski reported[2] a vulnerability in
the mail() function which could be used to bypass PHP's safe mode
setting and execute any program as if this mode was not enabled.
Since PHP 4.0.5, the mail() function has a fifth parameter which is
used to pass additional command line parameters to the sendmail
binary. It is possible to use this parameter to change the behaviour
of sendmail and use it to execute arbitrary programs or scripts.
The updated PHP packages disallow the use of this fifth parameter if
safe mode is in use.
This vulnerability affects Conectiva Linux 7.0 and 8 if safe mode is
in use. Conectiva Linux 6.0 was shipped with an earlier version of
PHP which does not have this parameter.

2) Control characters injection[4]
Wojciech Purczynski also reported that it is possible
to insert ASCII control characters (such as 'n') in the text
supplied as parameter to the mail() function. Depending on how the
PHP script handles user input (wheter it is filtered or not, and
how), this could be used to add other mail headers to the message.
This vulnerability affects PHP4 and PHP3. The fix applied to the
packages listed here change such characters, if found in the
"subject" or "to" parameter, to a white space (" ").
In a similar way, other functions such as fopen() also accept control
characters in their parameters. This is now also being filtered, and
such characters are being changed to "_" (underscore).

3) Old file upload vulnerability[4][6]
While preparing the updates for the above issues, it has come to our
attention that the PHP3 packages in Conectiva Linux 7.0 were not
updated regarding the file upload vulnerability which was addressed
in the CLSA-2002:468[6] advisory. PHP4 is the default PHP package for
that distribution and PHP3 was shipped in the second CD only for
backwards compatibility. The PHP3 packages for CL 7.0 have now been

It is recommended that all PHP users upgrade their packages.

IMPORTANT: if PHP is being used as an Apache module, the web server
has to be restarted after the upgrade if it was already running. To
do so, please run, as root:

service httpd stop

(wait a few seconds and check with "ps ax|grep httpd" if there are
any httpd processes running. On a busy webserver this could take a
little longer.)

service httpd start



Users of Conectiva Linux version 6.0 or higher may use apt to perform
upgrades of RPM packages:
- add the following line to /etc/apt/sources.list if it is not there yet
(you may also use linuxconf to do this):

rpm [cncbr] 6.0/conectiva updates

(replace 6.0 with the correct version number if you are not running CL6.0)

- run: apt-get update
- after that, execute: apt-get upgrade

Detailed instructions reagarding the use of apt and upgrade examples
can be found at

- -------------------------------------------------------------------------
All packages are signed with Conectiva's GPG key. The key and instructions
on how to import it can be found at
Instructions on how to check the signatures of the RPM packages can be
found at
- -------------------------------------------------------------------------
All our advisories and generic update instructions can be viewed at

- -------------------------------------------------------------------------
subscribe: [email protected]
unsubscribe: [email protected]
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: For info see


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