An issue was discovered on Securifi Almond, Almond+, and Almond 2015 devices with…

Summary

An issue was discovered on Securifi Almond, Almond+, and Almond 2015 devices with firmware AL-R096. The device provides a user with the capability of adding new routes to the device. It seems that the POST parameters passed in this request to set up routes on the device can be set in such a way that would result in passing commands to a "popen" API in the function and thus result in command injection on the device. If the firmware version AL-R096 is dissected using binwalk tool, we obtain a cpio-root archive which contains the filesystem set up on the device that contains all the binaries. The binary "goahead" is the one that has the vulnerable function that receives the values sent by the POST request. If we open this binary in IDA-pro we will notice that this follows a MIPS little endian format. The function sub_00420F38 in IDA pro is identified to be receiving the values sent in the POST request and the value set in POST parameter "dest" is extracted at address 0x00420FC4. The POST parameter "dest is concatenated in a route add command and this is passed to a "popen" function at address 0x00421220. This allows an attacker to provide the payload of his/her choice and finally take control of the device.