Western Digital My Cloud Command Injection / File Upload
Posted on 07 March 2017
SEC Consult Vulnerability Lab Security Advisory < 20170307-0 > ======================================================================= title: Unauthenticated OS command injection & arbitrary file upload product: Western Digital My Cloud vulnerable version: at least: 2.21.126 (My Cloud), 2.11.157(My Cloud EX2), 2.21.126 (My Cloud EX2 Ultra), 2.11.157 (My Cloud EX4), 2.21.126 (My Cloud EX2100), 2.21.126 (My Cloud EX4100), 2.11.157 (My Cloud Mirror), 2.21.126 (My Cloud Mirror Gen2), 2.21.126 (My Cloud PR2100), 2.21.126 (My Cloud PR4100), 2.21.126 (My Cloud DL2100), 2.21.126 (My Cloud DL4100) fixed version: - CVE number: - impact: Critical homepage: https://www.wdc.com/en-um/ found: 2017-01-17 by: Wan Ikram (Office Kuala Lumpur) Fikri Fadzil (Office Kuala Lumpur) SEC Consult Vulnerability Lab An integrated part of SEC Consult Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich https://www.sec-consult.com ======================================================================= Vendor description: ------------------- "Reliable, centralized personal storage with automatic backup that plugs into your own home network. Share whatever you want, anywhere you have an Internet connection." Source: https://www.wdc.com/products/personal-cloud-storage/my-cloud.html Business recommendation: ------------------------ By combining the vulnerabilities documented in this advisory an attacker can fully compromise a WD My Cloud device. In the worst case one could steal sensitive data stored on the device or use it as a jump host for further internal attacks. SEC Consult recommends not to attach WD My Cloud to the network until a thorough security review has been performed by security professionals and all identified issues have been resolved. Vulnerability overview/description: ----------------------------------- The firmware doesn't apply proper validation on many user inputs. As a result, below vulnerabilities could be exploited by unauthenticated attackers to fully compromise the device. 1. Unauthenticated OS Command Injection Any OS commands can be injected by unauthenticated attackers. This is a serious vulnerability as the chances for the device to be fully compromise is very high. 2. Unauthenticated Arbitrary File Upload A malicious file can be uploaded into the webserver with no authentication required. It is possible for an attacker to upload a script to issue operating system commands. 3. Cross Site Request Forgery (CSRF) There is no anti-CSRF mechanism implemented in the firmware. Due to this, an attacker can force a user to execute any action through any script. As the vulnerabilities described in 1) and 2) do not need authentication, those can be exploited via CSRF over the Internet as well! Proof of concept: ----------------- 1. Unauthenticated OS Command Injection Below is a sample cURL request to execute arbitrary OS command for one of vulnerable scripts. $ curl http://$IP/web/addons/jqueryFileTree.php?host=x&pwd=x&user=x&dir=x&lang=x"; <os-command-here>; echo "x 2. Unauthenticated Arbitrary File Upload Below is the cURL request to upload arbitrary files on the webserver. $ curl -F "file=@shell.php" http://$IP/web/addons/upload.php?name=x&folder=<target-upload-directory>&index=<script-name> 3. Cross Site Request Forgery (CSRF) There is no anti-CSRF mechanism implemented for all accessible scripts in the firmware. Vulnerable / tested versions: ----------------------------- The following device & firmware has been tested and found to be vulnerable: 2.11.157 (My Cloud EX2) As the firmware used by all My Cloud devices are more or less similar, we believe the other versions are also prone to the same vulnerabilities. This could be verified by using the IoT Inspector software for automated firmware analysis. Vendor contact timeline: ------------------------ 2017-01-18: Contacting vendor through "WD Support - Create a Support Case" page (https://support.wdc.com/support/case.aspx?lang=en). Assigned ticket number - 011817-11728265. 2017-01-19: Vendor: replies to the ticket asking for more clarification. 2017-01-20: Replied to the vendor, requesting security contact and encryption keys 2017-01-23: Vendor: "we don't have a security department that we could forward this concern" 2017-01-23: Telling support that there seems to be a security contact by referencing other WD advisories, requesting security contact again 2017-01-24: Vendor: asking for affected product name and firmware version. 2017-01-24: Providing list of affected product name and firmware versions, requesting security contact again 2017-01-25: Vendor: informs us that they "have already escalated the case from their back end team", they will update us. 2017-02-09: Requesting a status update 2017-02-10: Vendor (support): back end team is already informed, they will follow up 2017-02-10: Vendor security contact emails us 2017-02-16: Asking for encryption information to send advisory 2017-02-16: Vendor (security contact): requests security advisory to be shared over unencrypted channel 2017-02-20: Provided advisory and proof of concept through insecure channel as requested 2017-02-21: Vendor (security contact): requesting extension of deadline to a period of 90 days from the date of detail disclosure 2017-02-22: Informing the vendor that we grant extension of disclosure but not from detail disclosure date (2017-02-20), but from initial contact date (2017-01-18) as they could have reacted faster in the first place Set latest disclosure date to 2017-04-19 (no answer from vendor) 2017-03-03: 3rd party researcher discloses many 0-days, containing our findings as well, https://www.exploitee.rs/index.php/Western_Digital_MyCloud 2017-03-07: Informing vendor security contact of our public disclosure 2017-03-07: Public disclosure of advisory Solution: --------- There is currently no update available from the vendor. Workaround: ----------- None Advisory URL: ------------- https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Vulnerability Lab SEC Consult Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich About SEC Consult Vulnerability Lab The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It ensures the continued knowledge gain of SEC Consult in the field of network and application security to stay ahead of the attacker. The SEC Consult Vulnerability Lab supports high-quality penetration testing and the evaluation of new offensive and defensive technologies for our customers. Hence our customers obtain the most current information about vulnerabilities and valid recommendation about the risk profile of new technologies. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Interested to work with the experts of SEC Consult? Send us your application https://www.sec-consult.com/en/Career.htm Interested in improving your cyber security with the experts of SEC Consult? Contact our local offices https://www.sec-consult.com/en/About/Contact.htm ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Mail: research at sec-consult dot com Web: https://www.sec-consult.com Blog: http://blog.sec-consult.com Twitter: https://twitter.com/sec_consult EOF Fikri Fadzil / @2017
