CVE-2025-67460

Executive Summary

CVE-2025-67460 is a high-severity (CVSS 7.8) privilege escalation vulnerability affecting Zoom Rooms for Windows prior to version 6.6.0. The flaw resides in a protection mechanism failure against software downgrade attacks. An unauthenticated attacker with local access can exploit this weakness to escalate privileges, potentially gaining SYSTEM-level control over the affected host. The vulnerability is currently unpatched in older versions, with the fix available in Zoom Rooms 6.6.0. No public proof-of-concept (PoC) or exploit code has been identified at this time.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a native Windows application vulnerability within the Zoom Rooms software distribution.

CVSS Breakdown & Threat Level

• CVSS Score: 7.8 (High)
• Attack Vector: Local (AV:L)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

The high CVSS score reflects the low attack complexity and the lack of required privileges or user interaction. An attacker with local access can fully compromise the system's confidentiality, integrity, and availability.

Deep Dive & Mechanics

The vulnerability is classified as CWE-1329: Protection Mechanism Failure of Software Downgrade. This occurs when the application fails to properly validate or enforce integrity checks during the software update or rollback process. In Zoom Rooms for Windows, the mechanism intended to prevent downgrading to a vulnerable version is flawed.

An attacker with local access can exploit this by:

1. Intercepting or manipulating the update process.
2. Forcing the installation of an older, vulnerable version of Zoom Rooms.
3. Once the downgraded version is installed, the attacker can leverage known vulnerabilities in that older version to escalate privileges.

The root cause is likely insufficient cryptographic verification of update packages or a lack of proper version rollback restrictions. The attacker does not need authentication, only the ability to write to the local filesystem or manipulate network traffic (if the update is fetched locally).

Vulnerable vs. Patched Code

Since no specific code diff is publicly available, the following is a hypothetical representation of the vulnerable and patched logic.

Vulnerable Code (Zoom Rooms < 6.6.0):

// Vulnerable: No version check before applying update
void ApplyUpdate(string updatePackagePath) {
    // Directly applies the update without verifying version
    InstallPackage(updatePackagePath);
}

Patched Code (Zoom Rooms >= 6.6.0):

// Patched: Version check enforced
void ApplyUpdate(string updatePackagePath) {
    Version newVersion = GetPackageVersion(updatePackagePath);
    Version currentVersion = GetCurrentVersion();
    
    if (newVersion < currentVersion) {
        LogError("Downgrade attempt blocked.");
        return;
    }
    
    InstallPackage(updatePackagePath);
}

The patched version introduces a version comparison to prevent downgrades. The vulnerable version lacks this check, allowing an attacker to install an older, exploitable build.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• Local access to a Windows host running Zoom Rooms < 6.6.0.
• Ability to write to the Zoom Rooms installation directory or manipulate the update source.

Exploitation Steps:

1. Identify the current Zoom Rooms version (e.g., via C:\Program Files\Zoom\Rooms\Zoom.exe properties).
2. Obtain an older, vulnerable Zoom Rooms installer (e.g., version 6.5.0).
3. Replace the legitimate update package or modify the update configuration to point to the malicious older version.
4. Trigger the update process (e.g., via ZoomRooms.exe --update or by restarting the service).
5. Once the downgrade is complete, exploit a known privilege escalation in the older version (e.g., CVE-2024-XXXXX).
6. Escalate to SYSTEM.

Example PowerShell script (conceptual):

# Stop Zoom Rooms service
Stop-Service -Name "ZoomRooms"

# Replace update package
Copy-Item -Path "C:\malicious\ZoomRooms_6.5.0.msi" -Destination "C:\ProgramData\Zoom\Updates\ZoomRooms.msi" -Force

# Restart service to trigger update
Start-Service -Name "ZoomRooms"

Blue Team (Defensive)

Detection:

• Monitor for unexpected service restarts or file modifications in the Zoom Rooms installation directory.
• Alert on installation of Zoom Rooms versions older than 6.6.0.
• Use Sysmon to log process creation and file writes to C:\ProgramData\Zoom\Updates\.

Hunting Queries:

• Windows Event Log (4688): Look for ZoomRooms.exe or msiexec.exe executed with suspicious command-line arguments.
• File Integrity Monitoring: Track changes to ZoomRooms.exe and ZoomRooms.msi files.

Indicators of Compromise (IOCs)

• File Hashes (SHA-256): (Placeholder - replace with actual hashes if discovered)
  • ZoomRooms_6.5.0.msi: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Registry Keys:
  • HKLM\SOFTWARE\Zoom\Rooms\UpdateVersion (modified to an older version)
• Network Indicators:
  • Connections to non-standard update servers (e.g., IP addresses not belonging to Zoom's CDN).
• Process Indicators:
  • msiexec.exe executing with /i and a path to a non-standard MSI file.
  • ZoomRooms.exe launched with --update flag.

Detection Engineering

YARA Rule

rule CVE_2025_67460_Zoom_Downgrade {
    meta:
        description = "Detects Zoom Rooms installer files that may be used in a downgrade attack"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
    strings:
        $s1 = "ZoomRooms" nocase
        $s2 = "6.5." nocase
        $s3 = "6.4." nocase
        $s4 = "6.3." nocase
    condition:
        uint16(0) == 0x5A4D and  // MZ header
        all of ($s*) and
        filesize < 200MB
}

Sigma Rule

title: Zoom Rooms Downgrade Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects attempts to downgrade Zoom Rooms to a vulnerable version
author: Valters IT
date: 2025/04/10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\msiexec.exe'
        CommandLine|contains: 'ZoomRooms'
        CommandLine|contains: '6.5.'
    condition: selection
falsepositives:
    - Legitimate updates from Zoom (should be version >= 6.6.0)
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET 443 (msg:"CVE-2025-67460 - Zoom Rooms Downgrade Attempt"; flow:to_server,established; content:"ZoomRooms"; nocase; content:"6.5."; nocase; distance:0; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade Zoom Rooms: Update all Zoom Rooms for Windows installations to version 6.6.0 or later.
2. Restrict Local Access: Limit physical and remote desktop access to Zoom Rooms hosts to authorized personnel only.
3. Disable Automatic Updates (Temporary): If patching is delayed, disable automatic updates and manually verify update integrity.

Long-Term Mitigations:

• Implement application whitelisting to prevent unauthorized executables (e.g., older MSI installers).
• Enable Windows Defender Application Control (WDAC) or AppLocker.
• Monitor for downgrade attempts using the provided detection rules.
• Conduct regular vulnerability scans on Zoom Rooms hosts.

Patch Details:

• Fixed Version: Zoom Rooms for Windows 6.6.0
• Vendor Advisory: Zoom Security Bulletin (search for CVE-2025-67460)

Valters IT
Securing Digital Frontiers