Zoom RCE Flaw Also Affects Its Rebranded Versions RingCentral and Zhumu

Jul 16, 2019

The same security vulnerabilities that were recently reported
in Zoom for macOS
also affect two other popular video conferencing software that
under the hood, are just a rebranded version of Zoom video
conferencing software.

Security researchers confirmed The Hacker News that RingCentral,
used by over 350,000 businesses, and Zhumu, a Chinese version of
Zoom, also runs a hidden local web server on users’ computers, just
like Zoom for macOS.

The controversial local web server that has been designed to
offer an automatic click-to-join feature was found vulnerable to
remote command injection attacks through 3rd-party
websites.

Security researcher Jonathan Leitschuh initially provided a
proof-of-concept demonstrating how the vulnerable web
server could eventually allow attackers to turn on users
laptop’s webcam and microphone remotely.

The flaw was later escalated to remote code execution attack by
another security researcher, Karan Lyons, who has
now published a new video demonstration confirming the same RCE
flaw in RingCentral and Zhumu for macOS users.
^[3]

RingCentral has already released an updated version (v7.0.151508.0712) of its meeting app for
macOS that patches both vulnerabilities by removing the vulnerable
web server installed by the video conferencing software.

As explained in our previous article by Mohit Kumar, Apple
released a silent update for its macOS users to remove the Zoom
local web server (ZoomOpener daemon) for all users. However, Apple
update did not remove the local server installed by RingCentral and
Zhumu.

Therefore, users who are still using the RingCentral video
conferencing software are highly recommended to update their
systems to the latest patched version of the software.

“All users that have installed RingCentral Meetings on MacOS should
accept the update. Please ensure that all RingCentral Meetings
MacOS versions prior to v7.0.151508.0712 are removed,” the company
says.

“RingCentral is continuing to work on addressing the General
Concern related to ‘Video ON Concern’ for additional platforms. We
will continue to provide updates.”

However, the software update could not protect former customers who
are not using the software anymore but have the vulnerable
web-server still activated on their systems unknowingly.

Those users are advised to remove the hidden
web server ^[5] manually by running
commands provided by the researcher on GitHub.

However, the Chinese app Zhumu has not yet released a patch for
their software, but users can still uninstall the server following
the same terminal commands.

^[1]^[2]^[4]

References

^{^}
Zoom for macOS
(thehackernews.com)
^{^}
vulnerable web server
(thehackernews.com)
^{^}
Karan Lyons
(twitter.com)
^{^}
v7.0.151508.0712
(support.ringcentral.com)
^{^}
remove the hidden web server
(gist.github.com)

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OWASP TOP !0

Injection. Injection flaws, such as SQL, NoSQL, OS, and LDAP injection, occur when untrusted data is sent to an interpreter as part of a command or query. The attacker’s hostile data can trick the interpreter into executing unintended commands or accessing data without proper authorization. Broken Authentication. Application functions related to authentication and session management are often implemented incorrectly, allowing attackers to compromise passwords, keys, or session tokens, or to exploit other implementation flaws to assume other users’ identities temporarily or permanently. Sensitive Data Exposure. Many web applications and APIs do not properly protect sensitive data, such as financial, healthcare, and PII. Attackers may steal or modify such weakly protected data to conduct credit card fraud, identity theft, or other crimes. Sensitive data may be compromised without extra protection, such as encryption at rest or in transit, and requires special precautions when exchanged with the browser. XML External Entities (XXE). Many older or poorly configured XML processors evaluate external entity references within XML documents. External entities can be used to disclose internal files using the file URI handler, internal file shares, internal port scanning, remote code execution, and denial of service attacks. Broken Access Control. Restrictions on what authenticated users are allowed to do are often not properly enforced. Attackers can exploit these flaws to access unauthorized functionality and/or data, such as access other users’ accounts, view sensitive files, modify other users’ data, change access rights, etc. Security Misconfiguration. Security misconfiguration is the most commonly seen issue. This is commonly a result of insecure default configurations, incomplete or ad hoc configurations, open cloud storage, misconfigured HTTP headers, and verbose error messages containing sensitive information. Not only must all operating systems, frameworks, libraries, and applications be securely configured, but they must be patched/upgraded in a timely fashion. Cross-Site Scripting XSS. XSS flaws occur whenever an application includes untrusted data in a new web page without proper validation or escaping, or updates an existing web page with user-supplied data using a browser API that can create HTML or JavaScript. XSS allows attackers to execute scripts in the victim’s browser which can hijack user sessions, deface web sites, or redirect the user to malicious sites. Insecure Deserialization. Insecure deserialization often leads to remote code execution. Even if deserialization flaws do not result in remote code execution, they can be used to perform attacks, including replay attacks, injection attacks, and privilege escalation attacks. Using Components with Known Vulnerabilities. Components, such as libraries, frameworks, and other software modules, run with the same privileges as the application. If a vulnerable component is exploited, such an attack can facilitate serious data loss or server takeover. Applications and APIs using components with known vulnerabilities may undermine application defenses and enable various attacks and impacts. Insufficient Logging & Monitoring. Insufficient logging and monitoring, coupled with missing or ineffective integration with incident response, allows attackers to further attack systems, maintain persistence, pivot to more systems, and tamper, extract, or destroy data. Most breach studies show time to detect a breach is over 200 days, typically detected by external parties rather than internal processes or monitoring.

Zoom RCE Flaw Also Affects Its Rebranded Versions RingCentral and Zhumu

References

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