OpenSSL TLS 1.1 and 1.2 AES-NI DoS - Metasploit


This page contains detailed information about how to use the auxiliary/dos/ssl/openssl_aesni metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Table Of Contents
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Module Overview

Name: OpenSSL TLS 1.1 and 1.2 AES-NI DoS
Module: auxiliary/dos/ssl/openssl_aesni
Source code: modules/auxiliary/dos/ssl/openssl_aesni.rb
Disclosure date: 2013-02-05
Last modification time: 2020-10-02 17:38:06 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: -
Target network port(s): 443
List of CVEs: CVE-2012-2686

The AES-NI implementation of OpenSSL 1.0.1c does not properly compute the length of an encrypted message when used with a TLS version 1.1 or above. This leads to an integer underflow which can cause a DoS. The vulnerable function aesni_cbc_hmac_sha1_cipher is only included in the 64-bit versions of OpenSSL. This module has been tested successfully on Ubuntu 12.04 (64-bit) with the default OpenSSL 1.0.1c package.

Module Ranking and Traits

Module Ranking:

  • normal: The exploit is otherwise reliable, but depends on a specific version and can't (or doesn't) reliably autodetect. More information about ranking can be found here.

Basic Usage

msf > use auxiliary/dos/ssl/openssl_aesni
msf auxiliary(openssl_aesni) > show targets
    ... a list of targets ...
msf auxiliary(openssl_aesni) > set TARGET target-id
msf auxiliary(openssl_aesni) > show options
    ... show and set options ...
msf auxiliary(openssl_aesni) > exploit

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 dos/ssl/openssl_aesni auxiliary module looks in the msfconsole:

msf6 > use auxiliary/dos/ssl/openssl_aesni

msf6 auxiliary(dos/ssl/openssl_aesni) > show info

       Name: OpenSSL TLS 1.1 and 1.2 AES-NI DoS
     Module: auxiliary/dos/ssl/openssl_aesni
    License: Metasploit Framework License (BSD)
       Rank: Normal
  Disclosed: 2013-02-05

Provided by:
  Wolfgang Ettlinger <[email protected]>

Check supported:
  No

Basic options:
  Name       Current Setting  Required  Description
  ----       ---------------  --------  -----------
  MAX_TRIES  300              yes       Maximum number of tries
  RHOSTS                      yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT      443              yes       The target port (TCP)

Description:
  The AES-NI implementation of OpenSSL 1.0.1c does not properly 
  compute the length of an encrypted message when used with a TLS 
  version 1.1 or above. This leads to an integer underflow which can 
  cause a DoS. The vulnerable function aesni_cbc_hmac_sha1_cipher is 
  only included in the 64-bit versions of OpenSSL. This module has 
  been tested successfully on Ubuntu 12.04 (64-bit) with the default 
  OpenSSL 1.0.1c package.

References:
  https://nvd.nist.gov/vuln/detail/CVE-2012-2686
  https://www.openssl.org/news/secadv/20130205.txt

Module Options

This is a complete list of options available in the dos/ssl/openssl_aesni auxiliary module:

msf6 auxiliary(dos/ssl/openssl_aesni) > show options

Module options (auxiliary/dos/ssl/openssl_aesni):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   MAX_TRIES  300              yes       Maximum number of tries
   RHOSTS                      yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT      443              yes       The target port (TCP)

Advanced Options

Here is a complete list of advanced options supported by the dos/ssl/openssl_aesni auxiliary module:

msf6 auxiliary(dos/ssl/openssl_aesni) > show advanced

Module advanced options (auxiliary/dos/ssl/openssl_aesni):

   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
   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

Auxiliary Actions

This is a list of all auxiliary actions that the dos/ssl/openssl_aesni module can do:

msf6 auxiliary(dos/ssl/openssl_aesni) > show actions

Auxiliary actions:

   Name  Description
   ----  -----------

Evasion Options

Here is the full list of possible evasion options supported by the dos/ssl/openssl_aesni auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(dos/ssl/openssl_aesni) > 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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Error Messages

This module may fail with the following error messages:

Error Messages

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

No common ciphers!

Here is a relevant code snippet related to the "No common ciphers!" error message:

153:	      elsif cs == 0x0039 # DHE-RSA-AES256-SHA
154:	        p2 = p2_dhe
155:	      elsif cs == 0x0035 # AES256-SHA
156:	        p2 = p2_aes_sha
157:	      else
158:	        print_error("No common ciphers!")
159:	        return
160:	      end
161:	
162:	      sock.put(p2)
163:

DoS unsuccessful.

Here is a relevant code snippet related to the "DoS unsuccessful." error message:

174:	      disconnect
175:	
176:	    end
177:	
178:	    if success == false
179:	      print_error("DoS unsuccessful.")
180:	    end
181:	  end
182:	
183:	  def get_cipher_suite(resp)
184:	    offset = 0

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References

See Also

Check also the following modules related to this module:

Related Nessus plugins:

Authors

  • Wolfgang Ettlinger <wolfgang.ettlinger[at]gmail.com>

Version

This page has been produced using Metasploit Framework version 6.2.29-dev. For more modules, visit the Metasploit Module Library.

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