Several problems in CARE 2002
-------------------------------------
# What is CARE 2002?
CARE 2002 is a free software package for hospitals. It's based on php +
mysql. For further information visit <http://www.care2x.com/>.
#### include + NULL problem ####
# Problem description
There are several include statements which use variables passed by
the user. So if register_globals is on and magic_quotes_gpc is off you
are able to read any file on the webserver:
./main/cafenews.php:
[...]
include("../language/".$lang."/lang_".$lang."_newsdummy.php");
[...]
If $lang contains NULL (aka \0 or %00) the include statement ignores
everything after the NULL and includes the file.
Here's some metacode explaining the behavior:
foobar.php looks like this:
<?php
include("../".$input."blubb");
?>
Calling the file with the following parameter:
foobar.php?input=bla%00bla
results in (with enabled magic_quotes_gcp):
<br />
<b>Warning</b>: Failed opening '../bla\0blablubb' for inclusion
(include_path='.:/usr/local/lib/php') in <b>/home/user/public_html/foobar.php</b> on
line
<b>2</b><br />
This doesn't seem to be exploitable, but what happens, if magic_quotes_gcp
is turned off (like on php.ini-recommened, for performance reasons, without
pointing to THIS kind of problem)?:
<br />
<b>Warning</b>: Failed opening '../bla' for inclusion
(include_path='.:/usr/local/lib/php') in <b>/home/user/public_html/foobar.php</b> on
line
<b>2</b><br />
Huh?! Did you get it? Everything after NULL (%00) is ignored!
So what can we do now? We can take a look at the avaiable users:
foobar.php?input=../../../etc/passwd%00
Voila...
You can open every file you want. Ok, not every file. It has to be
readable by the http-user, like wwwrun or www.
# And the solution?
One can test, if a file exists with the function file_exists(). This
function doesn't ignore the characters after NULL.
On the other side, one could try to avoid using userdata to open a file.
In CARE 2002 and other webapps, you are often faced to this kind of
problem while handling language or themes files.
# Fix?
The authors will release a new version (1.0.0.2) at
<http://www.care2x.com/>.
The best way for a admin is, to enable magic_quotes_gpc and/or other
security related options in php. For further information take a look at:
<http://php.net/security> .
Other options, like enable_safe_mode or open_base_dir helps you too, to
keep your server privacy if you can't trust the executed phpcode.
#### missing addslashes() ####
# Problem description
None of the data passed (there are just a few exeptions) to the mysqld
is checked for control characters like ', " et al.
So one is able to commit injected sql queries.
The problem exists, when magic_quotes_gpc is turned off.
For further information about dangerous sql queries
see:
*<http://www.php.net/manual/en/security.database.php#security.database.sql-injection>.
* <http://www.google.com/search?q=sql+injection+problem>
# And the solution?
One can use addslashes() for _every_ data a user enters and is submitted
to the database.
Lazy people hope, that magic_quotes_gpc is enabled. Never expect, that an
admin configured a webserver correct, try to start the security at
application level.
# Fix?
Within the new release, the author fixed the problems.
Turn magic_quotes_qpc on!
##### Credits #####
Thanks skyp, for cross reading the text.
For the german-speaking folk: <http://bluephod.net/>
Sorry for the broken lines I hate webmailer :).
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