Dasan Networks GPON ONT WiFi Router H64X Series Authentication Bypass

Title: Dasan Networks GPON ONT WiFi Router H64X Series Authentication Bypass
Advisory ID: ZSL-2017-5421
Type: Local/Remote
Impact: Security Bypass
Risk: (4/5)
Release Date: 12.07.2017
Summary
H64xx is comprised of one G-PON uplink port and four ports of Gigabit Ethernet downlink supporting 10/100/1000Base-T (RJ45). It helps service providers to extend their core optical network all the way to their subscribers, eliminating bandwidth bottlenecks in the last mile. H64xx is integrated device that provide the high quality Internet, telephony service (VoIP) and IPTV or OTT content for home or office. H64xx enable the subscribers to make a phone call whose quality is equal to PSTN at competitive price, and enjoy the high quality resolution live video and service such as VoD or High Speed Internet.
Description
The vulnerable device does not properly perform authentication and authorization, allowing it to be bypassed through cookie manipulation. Setting the Cookie 'Grant' with value 1 (user) or 2 (admin) will bypass security controls in place enabling the attacker to take full control of the device management interface.
Vendor
Dasan Networks - http://www.dasannetworks.com
Affected Version
Model:
H640GR-02
H640GV-03
H640GW-02
H640RW-02
H645G

Firmware:
2.76-9999
2.76-1101
2.67-1070
Tested On
Server: lighttpd/1.4.31
Server: DasanNetwork Solution
Vendor Status
[19.05.2017] Vulnerability discovered.
[30.05.2017] Vendor contacted.
[30.05.2017] Vendor replied asking more details.
[31.05.2017] Sent details to the vendor.
[01.06.2017] Vendor provides latest firmware version 3.03-1144-01.
[01.06.2017] Working with the vendor.
[05.07.2017] Vendor responds that the 3.03 version has some fixes like backup file password security. Vendor asks if it's possible to test on latest version.
[05.07.2017] Replied to the vendor that if they provide a sample, we can execute.
[05.07.2017] Vendor provides public IP access to test version 3.03p1-1145. Config download fixed with 7z password protection.
[05.07.2017] Informed the vendor about the other issues.
[05.07.2017] Vendor replied.
[13.07.2017] Asked vendor for status update.
[13.07.2017] Vendor will fix remaining issues in next FW release. No confirmed date for new release.
[13.07.2017] Coordinated public security advisory released.
PoC
dasan-h64_auth.txt
Credits
Vulnerability discovered by Gjoko Krstic - <gjoko@zeroscience.mk>
References
N/A
Changelog
[12.07.2017] - Initial release
Contact
Zero Science Lab

Web: http://www.zeroscience.mk
e-mail: lab@zeroscience.mk