International Datacasting Corporation (IDC) SFX Series SuperFlex Satellite Receiver contains undocumented, hardcoded/insecure credentials for the xd user account. A remote unauthenticated attacker can log in via FTP using these credentials. Because the xd user has write permissions to their home directory where root-executed binaries and symlinks (such as those invoked by xdstartstop) are stored, the attacker can overwrite these files or manipulate symlinks to achieve arbitrary code execution as the root user.
Exploitability
AV:NAC:LAT:NPR:NUI:NVulnerable System
VC:LVI:NVA:NSubsequent System
SC:HSI:HSA:H7.9/CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:HOther