The AT&T U-verse 9.2.2h0d83 firmware for the Arris NVG589, NVG599, and unspecified other devices, when IP Passthrough mode is not used, configures an sbdc.ha WAN TCP service on port 61001 with the bdctest account and the bdctest password, which allows remote attackers to obtain sensitive information (such as the Wi-Fi password) by leveraging knowledge of a hardware identifier, related to the Bulk Data Collection (BDC) mechanism defined in Broadband Forum technical reports.
https://threatpost.com/bugs-in-arris-modems-distributed-by-att-vulnerable-to-trivial-attacks/127753/