Exploit.CVE202131728

Short bio

Exploit.CVE202131728 is Malwarebytes' detection name for 4 specific vulnerable drivers that can be used to disable security software

Type and source of infection

Incorrect access control in zam64.sys, zam32.sys allows a non-privileged process to open a handle, register itself with the driver, allocate executable memory, install a hook, and execute the executable memory using this hook, this exposes ring 0 code execution in the context of the driver allowing the non-privileged process to elevate privileges. We have found the files detected as Exploit.CVE202131728 to be used in so-called Bring Your Own Vulnerable Driver (BYOVD) attacks aimed at disabling security software on the targeted system.

Aftermath

If you are using software that depends on these drivers, you should check if there is a newer, non-vulnerable version available. If not, we would advise you to remove the software since there are ready-to-use exploits available for this vulnerability.

Protection

By removing this file, Malwarebytes protects users against the possible exploitation of the vulnerability listed as CVE-2021-31728.

Remediation

Malwarebytes can detect and remove Exploit.CVE202131728 without further user interaction.

1. Please download Malwarebytes to your desktop.
2. Double-click MBSetup.exe and follow the prompts to install the program.
3. When your Malwarebytes for Windows installation completes, the program opens to the Welcome to Malwarebytes screen.
4. Click on the Get started button.
5. Click Scan to start a Threat Scan.
6. Click Quarantine to remove the found threats.
7. Reboot the system if prompted to complete the removal process.

Add an exclusion

Should users wish to keep this program and exclude it from being detected in future scans, they can add the program to the exclusions list. Here’s how to do it.

• Open Malwarebytes for Windows.
• Click the Detection History
• Click the Allow List
• To add an item to the Allow List, click Add.
• Select the exclusion type Allow a file or folder and use the Select a folder button to select the main folder for the software that you wish to keep.
• Repeat this for any secondary files or folder(s) that belong to the software.

If you want to allow the program to connect to the Internet, for example to fetch updates, also add an exclusion of the type Allow an application to connect to the internet and use the Browse button to select the file you wish to grant access.