KL-001-2021-006: CommScope Ruckus IoT Controller Web Application Arbitrary Read/Write  
Title: CommScope Ruckus IoT Controller Web Application Arbitrary Read/Write  
Advisory ID: KL-001-2021-006  
Publication Date: 2021.05.26  
Publication URL:  
1. Vulnerability Details  
Affected Vendor: CommScope  
Affected Product: Ruckus IoT Controller  
Affected Version: and earlier  
Platform: Linux  
CWE Classification: CWE-250: Execution with Unnecessary Privileges  
CVE ID: CVE-2021-33217  
2. Vulnerability Description  
The IoT Controller web application includes a NodeJS module,  
node-red, which has the capability for users to read or write to  
local files on the IoT Controller. With the elevated privileges  
the web application runs as, this allowed for reading and  
writing to any file on the IoT Controller filesystem.  
3. Technical Description  
The Ruckus IoT Controller contains the node-red NodeJS  
Module. The node-red module has the built in functionality  
to read and write to files on the local filesystem of the  
IoT Controller.  
An authentication token is required. But a token is easily  
obtained due to hard-coded, default, unchangeable web application  
credentials (CVE-2021-33219).  
With the web application (and the node-red NodeJS module)  
running as root, this functionality can be leveraged to  
read or write to any file on the filesystem of the Ruckus  
IoT Controller.  
This condition was leveraged to add an account to the  
/etc/passwd file, then used to add a password hash to  
/etc/shadow. Additionally, the SSH daemon configuration was  
modified to ensure that the newly added account would be able  
to SSH in to the device. And to complete the escalation to  
root-level privileges, the newly added account was added to  
the /etc/sudoers configuration file.  
None of these steps would have been possible if the web  
application (and the node-red module as a result) had not been  
running as the 'root' user.  
4. Mitigation and Remediation Recommendation  
The vendor has released an updated firmware ( which  
remediates the described vulnerability. Firmware and release  
notes are available at:  
5. Credit  
This vulnerability was discovered by Jim Becher (@jimbecher)  
of KoreLogic, Inc.  
6. Disclosure Timeline  
2021.03.30 - KoreLogic submits vulnerability details to  
2021.03.30 - CommScope acknowledges receipt and the intention  
to investigate.  
2021.04.06 - CommScope notifies KoreLogic that this issue,  
along with several others reported by KoreLogic,  
will require more than the standard 45 business  
day remediation timeline.  
2021.04.06 - KoreLogic agrees to extend disclosure embargo if  
2021.04.30 - CommScope informs KoreLogic that remediation for  
this vulnerability will be available inside of the  
standard 45 business day timeline. Requests  
KoreLogic acquire CVE number for this  
2021.05.14 - 30 business days have elapsed since the  
vulnerability was reported to CommScope.  
2021.05.17 - CommScope notifies KoreLogic that the patched  
version of the firmware will be available the week  
of 2021.05.24.  
2021.05.19 - KoreLogic requests CVE from MITRE.  
2021.05.19 - MITRE issues CVE-2021-33217.  
2021.05.25 - CommScope releases firmware and associated  
2021.05.26 - KoreLogic public disclosure.  
7. Proof of Concept  
An excerpt of one of the POSTs, which is 16000+ bytes in length, is  
POST /node-red/flows HTTP/1.1  
and then there is a subsequent POST to inject/trigger the flow.  
root@vriot:~# tail -1 /etc/passwd  
jbecher2:x:18626:18626:Jim Becher,,,:/tmp:/bin/bash  
root@vriot:~# tail -1 /etc/shadow  
Note: the above hash is the same as the hash of the vriotha user,  
whose password is known to be 'nplus1user' (CVE-2021-33218).  
root@vriot:~# tail -2 /etc/ssh/sshd_config  
Match User jbecher2  
PasswordAuthentication yes  
root@vriot:~# tail -1 /etc/sudoers  
The contents of this advisory are copyright(c) 2021  
KoreLogic, Inc. and are licensed under a Creative Commons  
Attribution Share-Alike 4.0 (United States) License:  
KoreLogic, Inc. is a founder-owned and operated company with a  
proven track record of providing security services to entities  
ranging from Fortune 500 to small and mid-sized companies. We  
are a highly skilled team of senior security consultants doing  
by-hand security assessments for the most important networks in  
the U.S. and around the world. We are also developers of various  
tools and resources aimed at helping the security community.  
Our public vulnerability disclosure policy is available at: