Hitron CGNV4 modem/router multiple vulnerabilities
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Platforms / Firmware confirmed affected:
- Hitron CGNV4, 4.3.9.9-SIP-UPC
- Product page: http://www.hitrontech.com/en/cable_detail.php?id=62

Vulnerabilities
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Insecure session management

The web interface uses insecure cookies, which can be brute-forced
easily (e.g cookie: userid=0). If admin login is successful, the IP
address of the admin user is stored and everybody can access the
management interface with the same IP.

Missing CSRF protection

The web interface is not used any CSRF protection. In case of a valid
session exists, the attacker can modify any settings of the router. If
the default admin password was not changed, the attacker can perform a
login also and modify any settings after it.

Authenticated command injection

The ping diagnostic function is vulnerable to system command injection,
because the parameters are checked only at the client side. Using the
following ping target, the attacker can gain local root access to the
device:

“google.com;nc -l -p 1337 -e /bin/sh;echo”.

Disclaimer
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We found these vulnerabilities within a very short time range (3 hours),
and we did not check a lot of areas such as:
- Command injections in other modules
- Buffer overflows
- User authentication
- Default SSID and passphrase
- Analysis of the backup file
- Device configuration (such as SNMP)

Timeline
--------
- 2015.10.16: Vulnerabilities found in the Hitron CGNV4 were reported to UPC Magyarorszag and Liberty Global
- 2016.01.27: UPC Magyarorszag send out a repeated warning to its end users about the importance of the change of the default passphrases.
- 2016.02.16: Face to face meeting with Liberty Global security personnel in Amsterdam headquarters
- 2016.02.18: A proposal was sent to Liberty Global suggesting a wardriving experiment in Budapest, Hungary to measure the rate of end users who are still using the default passphrases.

Recommendations
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We do not know about any possible solution. Firmware update should
install the ISP after the fix will be ready.

Credits
-------
This vulnerability was discovered and researched by Gergely Eberhardt
from SEARCH-LAB Ltd. (www.search-lab.hu)

References
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[1] http://www.search-lab.hu/advisories/secadv-20160720