CVE-2021-30480 in Chat
Summary
by MITRE • 04/10/2021
Zoom Chat through 2021-04-09 on Windows and macOS allows certain remote authenticated attackers to execute arbitrary code without user interaction. An attacker must be within the same organization, or an external party who has been accepted as a contact. NOTE: this is specific to the Zoom Chat software, which is different from the chat feature of the Zoom Meetings and Zoom Video Webinars software.
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Analysis
by VulDB Data Team • 04/15/2021
The vulnerability identified as CVE-2021-30480 represents a critical remote code execution flaw within Zoom Chat software versions up to 2021-04-09 on Windows and macOS platforms. This security weakness specifically targets the chat functionality of Zoom's communication suite, distinguishing it from the chat features embedded within Zoom Meetings and Zoom Video Webinars applications. The vulnerability's exploitation requires an attacker to either be within the same organizational network or to have been granted contact access by a legitimate user, establishing a specific attack vector that leverages existing trust relationships within the Zoom ecosystem. The flaw enables authenticated attackers to execute arbitrary code on target systems without requiring any user interaction, making it particularly dangerous as it can be triggered silently during normal chat operations.
The technical nature of this vulnerability stems from improper input validation and handling within the Zoom Chat client software, creating a condition where malicious payloads can be processed and executed directly by the application. This type of flaw typically falls under CWE-74, which encompasses Improper Neutralization of Special Elements in Output Used by a Downstream Component, or potentially CWE-119, which addresses insufficient protection of memory. The vulnerability's design allows attackers to craft specially formatted messages or files that, when processed by the vulnerable Zoom Chat client, trigger unintended code execution. The authentication requirement means that attackers must already possess valid credentials or have established contact relationships within the organization, but once these conditions are met, the attack can proceed with full system compromise potential.
The operational impact of CVE-2021-30480 extends beyond simple privilege escalation, as it provides attackers with persistent access to organizational communication channels and potentially broader network resources. When an attacker successfully exploits this vulnerability, they gain the ability to execute malicious code with the privileges of the authenticated user, which could lead to data exfiltration, lateral movement within the network, or establishment of persistent backdoors. The fact that this vulnerability is specific to Zoom Chat rather than the broader Zoom platform means that organizations using other Zoom services remain unaffected, but conversely, those relying heavily on chat functionality face significant exposure. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as attackers can leverage the compromised chat client to execute arbitrary commands.
Organizations should implement immediate mitigation strategies including urgent software updates to the latest Zoom Chat versions, which address this vulnerability through proper input validation and code execution restrictions. Network segmentation and monitoring of chat traffic can help detect anomalous behavior that might indicate exploitation attempts, while user education regarding suspicious messages and the importance of keeping software updated remains crucial. The vulnerability's classification under ATT&CK framework as a privilege escalation vector underscores the importance of implementing least privilege principles and monitoring for unauthorized code execution. Security teams should also consider deploying endpoint detection and response solutions that can identify suspicious processes spawned from chat applications, as well as implementing network-based controls to restrict communication with potentially malicious endpoints that might be used for command and control operations.