Trendnet AC2600 TEW-827DRU version 2.08B01 does not properly implement csrf protections. Most pages lack proper usage of CSRF protections or mitigations. Additionally, pages that do make use of CSRF tokens are trivially bypassable as the server does not appear to validate them properly (i.e. re-using an old token or finding the token thru some other method is possible).
Trendnet AC2600 TEW-827DRU version 2.08B01 does not have sufficient access controls for the WAN interface. The default iptables ruleset for governing access to services on the device only apply to IPv4. All services running on the devices are accessible via the WAN interface via IPv6 by default.
Trendnet AC2600 TEW-827DRU version 2.08B01 improperly discloses information via redirection from the setup wizard. Authentication can be bypassed and a user may view information as Admin by manually browsing to the setup wizard and forcing it to redirect to the desired page.
Trendnet AC2600 TEW-827DRU version 2.08B01 contains a flaw in the session management for the device. The router's management software manages web sessions based on IP address rather than verifying client cookies/session tokens/etc. This allows an attacker (whether from a different computer, different web browser on the same machine, etc.) to take over an existing session. This does require the attacker to be able to spoof or take over original IP address of the original user's session.
Trendnet AC2600 TEW-827DRU version 2.08B01 lacks proper authentication to the bittorrent functionality. If enabled, anyone is able to visit and modify settings and files via the Bittorent web client by visiting: http://192.168.10.1:9091/transmission/web/
Trendnet AC2600 TEW-827DRU version 2.08B01 contains a symlink vulnerability in the bittorrent functionality. If enabled, the bittorrent functionality is vulnerable to a symlink attack that could lead to remote code execution on the device. If an end user inserts a flash drive with a malicious symlink on it that the bittorrent client can write downloads to, then a user is able to download arbitrary files to any desired location on the devices filesystem, which could lead to remote code execution. Example directories vulnerable to this include "config", "downloads", and "torrents", though it should be noted that "downloads" is the only vector that allows for arbitrary files to be downloaded to arbitrary locations.
Trendnet AC2600 TEW-827DRU version 2.08B01 contains an security flaw in the web interface. HTTPS is not enabled on the device by default. This results in cleartext transmission of sensitive information such as passwords.
Trendnet AC2600 TEW-827DRU version 2.08B01 makes use of hardcoded credentials. It is possible to backup and restore device configurations via the management web interface. These devices are encrypted using a hardcoded password of "12345678".
Trendnet AC2600 TEW-827DRU version 2.08B01 contains an improper access control configuration that could allow for a malicious firmware update. It is possible to manually install firmware that may be malicious in nature as there does not appear to be any signature validation done to determine if it is from a known and trusted source. This includes firmware updates that are done via the automated "check for updates" in the admin interface. If an attacker is able to masquerade as the update server, the device will not verify that the firmware updates downloaded are legitimate.