CVE-2021-23885
📋 TL;DR
This CVE describes an authenticated privilege escalation vulnerability in McAfee Web Gateway (MWG) that allows authenticated users to gain elevated privileges and execute arbitrary commands on the appliance. The vulnerability exists due to improper input neutralization in the troubleshooting page. Organizations running MWG versions prior to 9.2.8 are affected.
💻 Affected Systems
- McAfee Web Gateway (MWG)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An authenticated attacker gains full administrative control over the MWG appliance, allowing them to execute arbitrary commands, modify configurations, intercept traffic, and potentially pivot to other network resources.
Likely Case
An authenticated user with standard privileges escalates to administrator level, enabling them to bypass security controls, modify web filtering rules, and execute commands on the appliance.
If Mitigated
With proper access controls and network segmentation, the impact is limited to the MWG appliance itself, though administrative compromise still poses significant risk to web security controls.
🎯 Exploit Status
Exploitation requires authenticated access to the MWG web interface. The vulnerability is in the troubleshooting page where user input is not properly neutralized.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.2.8 and later
Vendor Advisory: https://kc.mcafee.com/corporate/index?page=content&id=SB10349
Restart Required: Yes
Instructions:
1. Download MWG version 9.2.8 or later from McAfee support portal. 2. Backup current configuration. 3. Apply the update through the MWG administration interface. 4. Restart the appliance as required.
🔧 Temporary Workarounds
Restrict User Access
allLimit access to the MWG web interface to only authorized administrators and reduce the number of users with authenticated access.
Network Segmentation
allIsolate MWG management interface to dedicated management network or VLAN, restricting access to authorized IP addresses only.
🧯 If You Can't Patch
- Implement strict access controls to limit which users can access the MWG web interface
- Monitor and audit all user activity on the MWG appliance, particularly access to the troubleshooting page
🔍 How to Verify
Check if Vulnerable:
Check the MWG version via the web interface under System > About. If version is below 9.2.8, the system is vulnerable.Check Version:
Connect to MWG web interface and navigate to System > About to view version information.Verify Fix Applied:
After updating, verify the version shows 9.2.8 or higher in the System > About page.📡 Detection & Monitoring
Log Indicators:
- Unusual user privilege escalation events
- Multiple failed authentication attempts followed by successful login
- Access to troubleshooting page by non-admin users
- Execution of unusual commands via the interface
Network Indicators:
- Unusual traffic patterns from MWG appliance
- Connections to unexpected external resources from MWG
SIEM Query:
source="mwg_logs" AND (event_type="privilege_escalation" OR event_type="troubleshooting_access" OR user="*" AND action="command_execution")