Zoom patches serious video conferencing bug

Zoom, a company that sells video conferencing software for the business market, patched a bug this week that could have allowed crooks to hijack customer video conferences.
Attackers with network access could have taken control of participating computers, according to researchers.
David Wells, a researcher at Tenable Security, reported the bug and provided an analysis including a proof of concept demonstration video explaining how attackers could compromise the Zoom system.
The vulnerability, which affected the Windows, Mac and Linux versions of Zoom’s software, lay in the way the company queued and processed messages in its software, Wells said.
This vulnerability affects the following Zoom versions:
- macOS 10.13, Zoom 4.1.33259.0925
- Windows 10, Zoom 4.1.33259.0925
- Ubuntu 14.04, Zoom 2.4.129780.0915
The internal mechanism that Zoom uses to send its network messages handles two kinds of network packet: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).
UDP doesn’t have the kind of handshaking and packet loss prevention overhead that you find in TCP packets, making it leaner and better suited for the latency-sensitive network communications that you find in audio and video conferencing.
TCP is therefore typically used to control sessions, while the simpler UDP protocol is used to send session content.
The messaging mechanism dispatches both kinds of packet to the same message handler program. Wells worked out a way to create a malformed UDP packet that the message handler interprets as a TCP message. The exploit works because the message handler isn’t validating the incoming messages to spot the malformed packet, according to Tenable’s synopsis.
The message handler accepts the UDP packets even when encrypted sessions are enabled, meaning that attackers do not need to authenticate themselves on the system first. That makes it possible for attackers outside of rogue meeting attendees to hijack a meeting. An attacker can be on the local network, or even on a WAN connection, suggests Wells, by brute-forcing the port that the victim is using for their UDP session with the Zoom server.
An attacker could take control of a computer by targeting a remote attendee sharing their screen during a session, said Tenable’s analysis. They could then bypass screen control permissions and send keystrokes and mouse movements directly to that participant’s machine. In practice, though, they’d have to avoid packet loss, which is a common occurrence in UDP sessions, and which could cause their keystrokes to go amiss. They would also have to avoid the victim noticing what they were doing and stopping them.
Tenable first gave Zoom the full details of this flaw on 11 October, and the video conferencing company released fixed versions for its Windows and Mac clients on 20 November, following up with a fix for the Linux client on 30 November.
Source: nakedsecurity
Industry: Unified communication news

Latest Jobs
-
- Identity Channel Partner Manager | London
- London
- N/A
-
Identity Channel Partner Manager | London Location: South East UK (commutable to London) We are working with a Cyber Security business who are looking for a Channel Partner Manager to drive and grow relationships across their identity ecosystem. Prior experience working within VARs, distributors, vendors or resellers in the identity space is essential. You must have experience working with technologies such as CyberArk, Sailpoint, Okta etc Responsibilities will include, but not be limited to: Build, maintain and develop strong relationships with channel partners. Work closely with partner sales teams to support growth drive sales opportunities. Identify and onboard new partners while strengthening existing partnerships. Act as the key point of contact for all channel-related activity. If you are an experienced channel professional, with experience in the Identity space and are ready for your next challenge, apply today.
-
- Service Architect- DACH regions
- Germany
- Upto €110,000 plus bonus and benefits
-
Lead Service Architect with the authority and experience to take control of complex, multi-million-euro outsourcing bids. This role is about leading the Service/ solutioning effort, bringing structure to chaos, and driving the entire bid team to deliver winning proposals. The company area a global managed services business working with enterprise and public sector clients, across Cloud, End-User Computing, Digital Workplace, Service Desk, and Network Infrastructure. What You’ll Do: Lead Service/ solution design from qualification to contract. Control bid teams — architects, pricing, delivery, and SMEs. Break down RFPs/RFIs into actionable, costed, client-ready solutions. Present internally and to clients at decision-maker level. Run solution workshops, own the architecture, and shape the financial model. You’ll Need: Experience working as a Service architect, Service Manager or Customer Success Manager R Gravitas to lead and drive teams through high-stakes bids. Deep knowledge of managed services delivery and commercial models. Strong technical grasp: Cloud, Security, EUC, Unified Comms, Service Desk, and more. Experience leading deals across onshore, offshore, and hybrid delivery models.
-
- Deal Architect- DACH region
- Germany
- Upto €110,000 plus bonus and benefits
-
Lead Deal Architect with the authority and experience to take control of complex, multi-million-euro outsourcing bids. This role is about leading the solutioning/ Service effort, bringing structure to chaos, and driving the entire bid team to deliver winning proposals. The company is a global managed services business providing solutions to enterprise and public sector clients, across Cloud, End-User Computing, Digital Workplace, Service Desk, and Network Infrastructure. What You’ll Do: Lead the deal from qualification to contract. Control bid teams — architects, pricing, delivery, and SMEs. Break down RFPs/RFIs into actionable, costed, client-ready solutions. Present internally and to clients at decision-maker level. Run solution workshops, own the architecture, and shape the financial model. Be responsible for the service Wrap and ensuring the Service meets clients requirements You’ll Need: A back ground with IT Services Experience in a similar type of role, for example: Deal, Service, or Solution Architect in ICT outsourcing. Gravitas to lead and drive teams through high-stakes bids. Deep knowledge of managed services delivery and commercial models. Strong technical knowledge: Cloud, Security, EUC, Unified Comms, Service Desk, and more. Experience leading deals across onshore, offshore, and hybrid delivery models.
-
- Pre Sales Lead- IT Services
- Germany
- Upto €100,000 plus benefits
-
As the Pre-Sales Lead (Sales Engineer/ Solution Architect) you will drive large-scale ICT managed services and outsourcing deals (from €0.5M to €20M+). You'll work directly with Business Development and clients to design high-impact solutions across Cloud (Azure, IaaS, SaaS, PaaS), EUC, Unified Comms, Security (SIEM, PAM), Networks, and Smart Workplaces. What You’ll Do: Lead the end-to-end pre-sales cycle — from RFI/RFP to contract. Design innovative, client-specific solutions with technical & commercial impact. Present at CxO level and steer proposal strategies & financial models. Collaborate closely with Portfolio, Service Desk, Field, and Digital Workplace teams. Support deal shaping with strong knowledge of ITIL, SIAM, Automation, and cost analysis. What You’ll Bring: Have strong experience in pre-sales or solution architecture. Experience with €M+ managed service deals. Deep technical expertise in modern ICT stack and enterprise IT services. Strong German (C1) and English communication skills. Certifications: ITIL v3/v4 required; SIAM, ISO20000 desirable.