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OpenCA Security Advisory: Cross Site Scripting vulnerability



OpenCA Security Advisory: Cross Site Scripting vulnerability

Authors
  Martin Bartosch <mb-bugtraq@xxxxxxxxx>
  Michael Bell <michael.bell@xxxxxxxxxxxxxxxx>

2004-09-01 Initial revision 
2004-09-06 Public release 

Summary
-------

The OpenCA Project is a collaborative effort to develop a robust, 
full-featured and Open Source out-of-the-box Certification Authority 
implementing the most used protocols with full-strength cryptography 
world-wide. OpenCA is based on many Open-Source Projects. Among the 
supported software is OpenLDAP, OpenSSL, Apache Project, Apache mod_ssl.

A Cross Site Scripting (XSS) vulnerability was found in the OpenCA PKI 
software, allowing users of the system to inject malicious HTML 
code into the system. The malicious code may even affect offline 
components.


Affected versions
-----------------

All versions of OpenCA, including 0.9.1-8 and 0.9.2 RC6.


Details
-------

Form input to the web frontends is not properly validated, making it
possible to inject malicious HTML code into the system. Once the
offending code has been inserted into the system, it may affect
PKI staff or other users accessing the data.

OpenCA advocates the separation between individual frontends and the
use of an offline CA and RA. In this case data is exchanged using
a removable medium such as a floppy disk. The offending code embedded
in the user data may thus be transferred even to systems not connected
to a network and might be used to attack offline nodes.


Impact
------

Cross site scripting attacks primarily affect the client system 
running the browser used to display the web page. OpenCA itself is
not directly affected by such attacks. However, XSS exploit
code may be deployed e. g. in order to gain session credentials, 
allowing for session takeover. More advanced attacks (requiring
specially crafted exploit code) could even be targeted at manipulating
data on the OpenCA node on the user's behalf.


Recommendations
---------------

All users of OpenCA should upgrade to a version that is not affected
by the problem.

OpenCA version 0.9.1 users are encouraged to upgrade to version 0.9.1-9.
Users of the current development branch 0.9.2 should upgrade to CVS
head.



References
----------

The Common Vulnerabilities and Exposures project (cve.mitre.org) has
assigned the name CAN-2004-0787 to this issue.

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0787

URL for this Security Advisory:
http://www.openca.org/news/CAN-2004-0787.txt



Appendix
--------

Security Patches

###########################################################################
## Patches against version 0.9.2
###########################################################################

Index: src/common/lib/functions/initServer
===================================================================
RCS file: /cvsroot/openca/openca-0.9/src/common/lib/functions/initServer,v
retrieving revision 1.40
diff -u -r1.40 initServer
--- src/common/lib/functions/initServer 30 Aug 2004 12:31:53 -0000      1.40
+++ src/common/lib/functions/initServer 1 Sep 2004 13:27:27 -0000
@@ -184,6 +184,10 @@
     $query->set_gettext (\&i18nGettext);
     close ($fh);
 
+    ## validate input data
+    ## 2004-08-27 Martin Bartosch <m.bartosch@xxxxxxxxx>
+    validateCGIParameters(\$query);
+
     ## reinit configuration
     my $CONFIG = $AUTOCONF {"etc_prefix"}.'/servers/'.$AUTOCONF
{"config_prefix"}.'.conf';
     if( not defined (my $ret = $config->loadCfg( "$CONFIG" )) ) {
Index: src/common/lib/functions/misc-utils.lib
===================================================================
RCS file:
/cvsroot/openca/openca-0.9/src/common/lib/functions/misc-utils.lib,v
retrieving revision 1.50
diff -u -r1.50 misc-utils.lib
--- src/common/lib/functions/misc-utils.lib     26 Aug 2004 14:08:03 -0000      
1.50
+++ src/common/lib/functions/misc-utils.lib     1 Sep 2004 13:27:27 -0000
@@ -443,4 +443,39 @@
     debug ($cmd, @_);
 }
 
+# 2004-08-31 Martin Bartosch <m.bartosch@xxxxxxxxx>
+# clean up CGI parameters
+# input: reference to CGI class instance
+# This function modifies the object itself
+sub validateCGIParameters {
+    my $queryref = shift;
+    
+    ## validate input data
+    ## 2004-08-27 Martin Bartosch <m.bartosch@xxxxxxxxx>
+    foreach my $param (keys %{$$queryref->Vars}) {
+       my @values = $$queryref->param($param);
+
+       # replace < and > with &lt; and &rt; for all CGI parameters passed
+       # NOTE/FIXME: unescaping might be necessary when actually
+       # passing this data to e. g. certificate generation routines
+       # to prevent literal XML entities in certificate contents
+       map { 
+           s/</&lt;/gm; 
+           s/>/&gt;/gm; 
+       } @values;
+       $$queryref->param(-name => $param, -value => @values);
+
+       # extra sanity check just to be sure (redundant)
+       foreach (@values) {
+           if (/<\S+.*?>/m) {
+               print "Content-type: text/html\n\n";
+               print "Security violation\n";
+               exit 101;
+           }
+       }
+    }
+    return $queryref;
+}
+
+
 1;




###########################################################################
## Patches against version 0.9.1-8
###########################################################################


Index: src/common/lib/functions/misc-utils.lib
===================================================================
RCS file:
/cvsroot/openca/openca-0.9/src/common/lib/functions/misc-utils.lib,v
retrieving revision 1.16.2.2
diff -u -r1.16.2.2 misc-utils.lib
--- src/common/lib/functions/misc-utils.lib     16 Apr 2003 13:24:51
-0000   1.16.2.2
+++ src/common/lib/functions/misc-utils.lib     1 Sep 2004 11:49:14 -0000
@@ -445,4 +445,38 @@
 
 }
 
+# 2004-08-31 Martin Bartosch <m.bartosch@xxxxxxxxx>
+# clean up CGI parameters
+# input: reference to CGI class instance
+# This function modifies the object itself
+sub validateCGIParameters {
+    my $queryref = shift;
+    
+    ## validate input data
+    ## 2004-08-27 Martin Bartosch <m.bartosch@xxxxxxxxx>
+    foreach my $param (keys %{$$queryref->Vars}) {
+       my @values = $$queryref->param($param);
+
+       # replace < and > with &lt; and &rt; for all CGI parameters passed
+       # NOTE/FIXME: unescaping might be necessary when actually
+       # passing this data to e. g. certificate generation routines
+       # to prevent literal XML entities in certificate contents
+       map { 
+           s/</&lt;/gm; 
+           s/>/&gt;/gm; 
+       } @values;
+       $$queryref->param(-name => $param, -value => @values);
+
+       # extra sanity check just to be sure (redundant)
+       foreach (@values) {
+           if (/<\S+.*?>/m) {
+               print "Content-type: text/html\n\n";
+               print "Security violation\n";
+               exit 101;
+           }
+       }
+    }
+    return $queryref;
+}
+
 1;
Index: src/web-interfaces/ca/ca.in
===================================================================
RCS file: /cvsroot/openca/openca-0.9/src/web-interfaces/ca/ca.in,v
retrieving revision 1.8.2.1
diff -u -r1.8.2.1 ca.in
--- src/web-interfaces/ca/ca.in 10 Nov 2003 13:10:48 -0000      1.8.2.1
+++ src/web-interfaces/ca/ca.in 1 Sep 2004 11:49:16 -0000
@@ -132,6 +132,9 @@
 ##// Now it's time to get the parameters passed over the web
 $query  = new OpenCA::TRIStateCGI;
 
+## validate input parameters 
+validateCGIParameters(\$query);
+
 ## Generate a new reference to Configuration ( instance )
 $dbconfig = new OpenCA::Configuration;
 $dbiconfig = new OpenCA::Configuration;
Index: src/web-interfaces/ldap/ldap.in
===================================================================
RCS file: /cvsroot/openca/openca-0.9/src/web-interfaces/ldap/ldap.in,v
retrieving revision 1.7.2.1
diff -u -r1.7.2.1 ldap.in
--- src/web-interfaces/ldap/ldap.in     10 Nov 2003 13:10:48 -0000      1.7.2.1
+++ src/web-interfaces/ldap/ldap.in     1 Sep 2004 11:49:16 -0000
@@ -138,6 +138,9 @@
 ##// Now it's time to get the parameters passed over the web
 $query  = new OpenCA::TRIStateCGI;
 
+## validate input parameters 
+validateCGIParameters(\$query);
+
 ## Generate a new reference to Configuration ( instance )
 $dbconfig = new OpenCA::Configuration;
 $dbiconfig = new OpenCA::Configuration;
Index: src/web-interfaces/node/node.in
===================================================================
RCS file: /cvsroot/openca/openca-0.9/src/web-interfaces/node/node.in,v
retrieving revision 1.2.2.1
diff -u -r1.2.2.1 node.in
--- src/web-interfaces/node/node.in     10 Nov 2003 13:10:48 -0000      1.2.2.1
+++ src/web-interfaces/node/node.in     1 Sep 2004 11:49:17 -0000
@@ -139,6 +139,9 @@
 ##// Now it's time to get the parameters passed over the web
 $query  = new OpenCA::TRIStateCGI;
 
+## validate input parameters 
+validateCGIParameters(\$query);
+
 ## Generate a new reference to Configuration ( instance )
 $dbconfig = new OpenCA::Configuration;
 $dbiconfig = new OpenCA::Configuration;
Index: src/web-interfaces/pub/pki.in
===================================================================
RCS file: /cvsroot/openca/openca-0.9/src/web-interfaces/pub/pki.in,v
retrieving revision 1.7.2.1
diff -u -r1.7.2.1 pki.in
--- src/web-interfaces/pub/pki.in       10 Nov 2003 13:10:48 -0000      1.7.2.1
+++ src/web-interfaces/pub/pki.in       1 Sep 2004 11:49:17 -0000
@@ -136,6 +136,9 @@
 ##// Now it's time to get the parameters passed over the web
 $query  = new OpenCA::TRIStateCGI;
 
+## validate input parameters 
+validateCGIParameters(\$query);
+
 ## Generate a new reference to Configuration ( instance )
 $dbconfig = new OpenCA::Configuration;
 $dbiconfig = new OpenCA::Configuration;
Index: src/web-interfaces/pub/scepd.in
===================================================================
RCS file: /cvsroot/openca/openca-0.9/src/web-interfaces/pub/Attic/scepd.in,v
retrieving revision 1.2.2.1
diff -u -r1.2.2.1 scepd.in
--- src/web-interfaces/pub/scepd.in     10 Nov 2003 13:10:48 -0000      1.2.2.1
+++ src/web-interfaces/pub/scepd.in     1 Sep 2004 11:49:17 -0000
@@ -121,6 +121,9 @@
 ##// Now it's time to get the parameters passed over the web
 $query  = new OpenCA::TRIStateCGI;
 
+## validate input parameters 
+validateCGIParameters(\$query);
+
 ## Generate a new reference to Configuration ( instance )
 $dbconfig = new OpenCA::Configuration;
 $dbiconfig = new OpenCA::Configuration;
Index: src/web-interfaces/ra/RAServer.in
===================================================================
RCS file: /cvsroot/openca/openca-0.9/src/web-interfaces/ra/RAServer.in,v
retrieving revision 1.8.2.1
diff -u -r1.8.2.1 RAServer.in
--- src/web-interfaces/ra/RAServer.in   10 Nov 2003 13:10:49 -0000      1.8.2.1
+++ src/web-interfaces/ra/RAServer.in   1 Sep 2004 11:49:18 -0000
@@ -138,6 +138,9 @@
 ##// Now it's time to get the parameters passed over the web
 $query  = new OpenCA::TRIStateCGI;
 
+## validate input parameters 
+validateCGIParameters(\$query);
+
 ## Generate a new reference to Configuration ( instance )
 $dbconfig = new OpenCA::Configuration;
 $dbiconfig = new OpenCA::Configuration;

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