Zero-Day Advisory

Fortinet Discovers Trend Micro Email Encryption Client DLL Preloading Vulnerability


Fortinet's FortiGuard Labs has discovered a DLL preloading vulnerability in Trend Micro Email Encryption Client.

Trend Micro Email Encryption Client is a commercial tool to keep your email confidential, simplify compliance, and reduce management costs by removing the complexity from encryption. It can send encrypted emails to anyone with identity based encryption, lower IT costs with hosted key service and ensure access to email with 24x7 key recovery.

Trend Micro Email Encryption Client is susceptible to a DLL preloading vulnerability. The issue occurs when the application looks to load a DLL for execution and an attacker provides a malicious DLL to use instead. The application generally follows a specific search path to locate the DLL. The vulnerability can be exploited by a simple file write (or potentially an over-write) which results in a foreign DLL running under the context of the application.


Users should apply the solution provided by Trend Micro.

Additional Information

Fortinet reported the vulnerability to Trend Micro on Jun. 6, 2017.

Trend Micro confirmed the vulnerability on Sep. 12, 2017.

Trend Micro patched the vulnerability on Nov. 16, 2017.


This vulnerability was discovered by Kushal Arvind Shah 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.