Sunday, May 30, 2021

CommScope Ruckus IoT Controller Web Application Arbitrary Read/Write

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.

[email protected]:~# tail -1 /etc/passwd
jbecher2:x:18626:18626:Jim Becher,,,:/tmp:/bin/bash

[email protected]:~# 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).

[email protected]:~# tail -2 /etc/ssh/sshd_config
Match User jbecher2
PasswordAuthentication yes

[email protected]:~# 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:


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Thanks for everything Templateism - You should have written the code a little more complicated