Zero-Day Advisory

Fortinet Discovers Malwarebytes Self-Protection Bypass Vulnerability


Fortinet's FortiGuard Labs has discovered a security bypass issue in Malwarebytes.

Malwarebytes is an anti-malware software for Microsoft Windows, macOS and Android that is developed by Malwarebytes Corporation. It is available in a free version, which scans for and removes malware when started manually, and a paid version, which additionally provides scheduled scans, real-time protection and a flash-memory scanner.

It has been discovered that Malwarebyte's self-defense driver can be manipulated by unprivileged users in order to disable product's critical functionalities. The vulnerability resides in MBAMChameleon which, upon successful exploitation, can be leveraged by adversary to tamper with the files, services and registries protected by the product.


Users should apply the solution provided by Malwarebytes.

Additional Information

Fortinet reported the vulnerability to Malwarebytes on January 12, 2017.

Malwarebytes patched the vulnerability on May 10, 2017.


This vulnerability was discovered by Wayne Low of Fortinet's FortiGuard Labs.

IPS Subscription

Fortinet customers who subscribe to Fortinet's intrusion prevention (IPS) service should be protected against this vulnerability with the appropriate configuration parameters in place. Fortinet's IPS service is one component of FortiGuard Subscription Services, which also offer comprehensive solutions such as antivirus, Web content filtering and antispam capabilities. These services enable protection against threats on both application and network layers. FortiGuard Services are continuously updated by FortiGuard Labs, which enables Fortinet to deliver a combination of multi-layered security intelligence and true zero-day protection from new and emerging threats. These updates are delivered to all FortiGate, FortiMail and FortiClient products. Fortinet strictly follows responsible disclosure guidelines to ensure optimum protection during a threat's lifecycle.