参考链接：https://ctftime.org/task/6263
After unpacking the firmware archive, you now have a binary in which to go hunting. Its now time to walk around the firmware and see if you can find anything.
解压之后是个.ext4文件，可以用zip来解压哦。解压后root目录里有个.mediapc_backdoor_password.gz，flag就在那里面
Google Capture The Flag 2018 (Quals) - Beginner's Quest - Reverse - Firmware
原文：https://www.cnblogs.com/Antiver/p/10292909.html