CVE-2023-49646 Overview
CVE-2023-49646 is an improper authentication vulnerability affecting multiple Zoom client applications and SDKs before version 5.16.5. This security flaw allows an authenticated user to conduct a denial of service attack via network access. The vulnerability stems from weaknesses in the authentication mechanisms (CWE-287: Improper Authentication) and improper verification of cryptographic signatures (CWE-347).
Critical Impact
An authenticated attacker can exploit this vulnerability to disrupt Zoom services for other users, potentially causing service outages across enterprise environments that rely on Zoom for critical communications.
Affected Products
- Zoom Meeting Software Development Kit (versions before 5.16.5)
- Zoom Video Software Development Kit (versions before 5.16.5)
- Zoom Virtual Desktop Infrastructure (versions before 5.16.5)
- Zoom Desktop Client for Windows, macOS, Linux (versions before 5.16.5)
- Zoom Mobile App for iOS and Android (versions before 5.16.5)
Discovery Timeline
- 2023-12-13 - CVE-2023-49646 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2023-49646
Vulnerability Analysis
This vulnerability represents an improper authentication flaw that can be exploited by users who have already authenticated to the Zoom platform. The vulnerability is associated with two CWE classifications: CWE-287 (Improper Authentication) and CWE-347 (Improper Verification of Cryptographic Signature), indicating that the authentication mechanism fails to properly validate certain security credentials or signatures.
The network-accessible nature of this vulnerability means attackers can exploit it remotely without requiring physical access to the target system. However, the requirement for prior authentication limits the attack surface to legitimate users or attackers who have obtained valid Zoom credentials.
Root Cause
The root cause of CVE-2023-49646 lies in the improper implementation of authentication controls within the Zoom client applications. Specifically, the vulnerability involves:
Improper Authentication (CWE-287): The affected Zoom clients fail to adequately verify that an actor claiming a specific identity is genuinely that actor, allowing authenticated users to perform actions that should be restricted.
Improper Verification of Cryptographic Signature (CWE-347): The software does not properly verify cryptographic signatures, which can allow attackers to forge or bypass authentication tokens.
Attack Vector
The attack vector for CVE-2023-49646 is network-based, requiring an authenticated user to initiate the attack. The exploitation scenario involves:
- An attacker first authenticates to a Zoom session using valid credentials
- The attacker then sends specially crafted requests that exploit the authentication weakness
- These requests bypass proper validation checks due to the cryptographic signature verification flaw
- The result is a denial of service condition affecting the availability of Zoom services
Since no verified exploit code is available for this vulnerability, the specific technical implementation of the attack remains limited to the information provided in Zoom's security bulletin. Organizations should review the Zoom Security Bulletin ZSB-23062 for additional technical details.
Detection Methods for CVE-2023-49646
Indicators of Compromise
- Unusual network traffic patterns originating from authenticated Zoom clients
- Abnormal authentication request volumes from individual user accounts
- Service disruptions or availability issues affecting Zoom meeting sessions
- Log entries showing repeated failed or malformed authentication attempts
Detection Strategies
- Monitor Zoom client versions across the enterprise to identify installations running versions prior to 5.16.5
- Implement network monitoring to detect anomalous traffic patterns to and from Zoom services
- Enable detailed logging on Zoom clients and review for authentication anomalies
- Deploy endpoint detection solutions to monitor Zoom application behavior
Monitoring Recommendations
- Establish baseline metrics for normal Zoom authentication patterns and alert on deviations
- Configure SIEM rules to correlate Zoom-related network activity with user behavior analytics
- Monitor for unexpected Zoom service degradation that could indicate active exploitation
- Track Zoom client update compliance across the organization through asset management tools
How to Mitigate CVE-2023-49646
Immediate Actions Required
- Upgrade all Zoom clients to version 5.16.5 or later immediately
- Inventory all systems running Zoom Meeting SDK, Video SDK, and VDI clients
- Prioritize patching systems used in critical business communications
- Review network access controls for Zoom traffic to limit potential attack surface
Patch Information
Zoom has released security updates to address this vulnerability. All affected products should be updated to version 5.16.5 or later. Detailed patch information is available in the Zoom Security Bulletin ZSB-23062.
The following products require updates:
- Zoom Desktop Client (Windows, macOS, Linux)
- Zoom Mobile App (iOS, Android)
- Zoom Meeting Software Development Kit
- Zoom Video Software Development Kit
- Zoom Virtual Desktop Infrastructure
Workarounds
- Restrict Zoom access to trusted network segments while awaiting patch deployment
- Implement additional network monitoring for Zoom traffic to detect potential exploitation attempts
- Consider temporary usage of Zoom web client as an alternative if client updates cannot be immediately deployed
- Enable enhanced logging on Zoom installations to support incident response if needed
# Configuration example
# Check Zoom client version on Windows systems
wmic product where "name like 'Zoom%%'" get name,version
# Check Zoom client version on macOS
defaults read /Applications/zoom.us.app/Contents/Info.plist CFBundleShortVersionString
# Check Zoom client version on Linux
zoom --version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
