Sunhillo SureLine Authentication Bypass via Session Cookie

Sunhillo SureLine before 9.1.5 contains an authentication bypass vulnerability that allows an unauthenticated remote attacker to impersonate any user with an active web session by forging a session cookie containing only a cleartext username with no random identifier or integrity protection. Attackers can guess default account names such as Admin or sftp_user and submit a forged username cookie to satisfy the login check in checkLogin (libwebcmn.so) and networkDiag.cgi, chaining into root command execution.