AdTran SRG 834-5 HDC17600021F1 devices (with SmartOS 11.1.1.1 and fixed in Version 12.1.3.1) have SSH enabled by default, accessible both over the LAN and the Internet. During a window of time when the device is being set up, it uses a default username and password combination of admin/admin with root-level privileges. An attacker can exploit this window to gain unauthorized root access by either modifying the existing admin account or creating a new account with equivalent privileges. This vulnerability allows attackers to execute arbitrary commands.
