CVE-2020-11469 in Client for Meetings
Summary
by MITRE
Zoom Client for Meetings through 4.6.8 on macOS copies runwithroot to a user-writable temporary directory during installation, which allows a local process (with the user's privileges) to obtain root access by replacing runwithroot.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/13/2024
The vulnerability identified as CVE-2020-11469 represents a critical privilege escalation flaw in the Zoom Client for Meetings version 4.6.8 and earlier on macOS systems. This issue stems from improper handling of temporary files during the installation process, creating a persistent security weakness that adversaries can exploit to gain elevated system privileges. The flaw specifically involves the installation routine's behavior of copying a privileged binary named runwithroot into a location accessible to regular user accounts.
The technical implementation of this vulnerability involves the installation script's failure to properly secure temporary directories where the runwithroot binary is placed. During the installation process, the system creates a temporary file in a user-writable directory, which serves as an attack surface for malicious actors. The runwithroot binary is designed to execute with root privileges, but due to the insecure temporary file placement, local processes can substitute the legitimate binary with a malicious replacement. This substitution allows the attacker to execute arbitrary code with root privileges, effectively bypassing the standard user permission model.
This vulnerability directly maps to CWE-732, which describes improper privilege management where a system allows an attacker to modify a privileged program or its execution environment. The flaw enables a local attacker to perform privilege escalation from user level to root access, representing a significant security risk for any system where Zoom is installed. The operational impact extends beyond individual machines as this vulnerability can be exploited by any local user to gain complete system control, potentially leading to data exfiltration, system compromise, or further lateral movement within a network environment.
The attack vector for this vulnerability is straightforward and requires minimal privileges to execute. An attacker with a standard user account can simply replace the legitimate runwithroot binary with a malicious version, then trigger the installation process or wait for the system to execute the binary automatically. This type of attack falls under the MITRE ATT&CK framework's privilege escalation techniques, specifically targeting the 'Valid Accounts' and 'Exploitation for Privilege Escalation' tactics. The vulnerability is particularly concerning because it does not require any special privileges beyond normal user access and can be exploited silently without detection.
Mitigation strategies for CVE-2020-11469 should include immediate patching of the Zoom client to version 4.6.9 or later, which addresses the insecure temporary file handling. System administrators should also implement monitoring for unauthorized modifications to critical system directories and temporary file locations. Additional protective measures include restricting write permissions to temporary directories, implementing file integrity monitoring solutions, and conducting regular security audits of installed applications. Organizations should also consider implementing application whitelisting policies to prevent unauthorized binaries from executing with elevated privileges, thereby reducing the attack surface for similar privilege escalation vulnerabilities.