Privilege escalation vulnerability in McAfee Web Gateway (MWG) UI

The impact of CVE-2021-23885 is significant due to its potential for privilege escalation. An attacker, once authenticated, can leverage this vulnerability to execute arbitrary commands on the McAfee Web Gateway appliance. This could allow them to modify configurations, access sensitive data stored on the appliance, or even pivot to other systems within the network. The ability to execute commands grants a high degree of control, enabling attackers to compromise the entire network if the MWG appliance is strategically positioned. This vulnerability shares similarities with other input validation flaws that have led to remote code execution on network appliances, highlighting the importance of robust security practices.

Organizations heavily reliant on McAfee Web Gateway for web filtering and security are at significant risk. Specifically, deployments with weak password policies or shared user accounts are more vulnerable. Environments where the MWG appliance is directly exposed to the internet without adequate network segmentation also face increased risk.

• windows / supply-chain: Examine scheduled tasks for suspicious entries related to MWG. Check event logs for unusual process executions or privilege escalations within the MWG appliance.

Get-ScheduledTask | Where-Object {$_.TaskName -like "*MWG*"}

• linux / server: Monitor system logs (journalctl) for authentication attempts followed by unusual command executions on the MWG appliance. Use auditd to track access to the troubleshooting page.

journalctl -u mcs-webgateway -f

• generic web: Examine MWG access logs for unusual requests targeting the troubleshooting page. Look for patterns indicative of input manipulation attempts.

 grep "/troubleshooting" /var/log/mcs-webgateway/access.log

1. 2021-02-17Disclosure

   disclosure

1. Reserviert2021-01-12
2. Veröffentlicht2021-02-17
3. Geändert2024-08-03
4. EPSS aktualisiert2026-04-02

The primary mitigation for CVE-2021-23885 is to upgrade McAfee Web Gateway to version 9.2.8 or later. If an immediate upgrade is not feasible, consider implementing temporary workarounds such as restricting access to the troubleshooting page to authorized personnel only. Review and strengthen authentication mechanisms to limit the number of authenticated users with access to the MWG. Monitor the MWG appliance for unusual activity, particularly attempts to access or modify system configurations. While a WAF might offer some protection, it is unlikely to fully mitigate the risk of privilege escalation. After upgrading, verify the fix by attempting to access the troubleshooting page with a standard user account and confirming that no elevated privileges can be obtained.