Zero-Day Advisory

Fortinet Discovers Naver Whale Browser DLL Preloading Vulnerability


Fortinet's FortiGuard Labs has discovered a DLL preloading vulnerability in Naver Whale for Windows.

Naver Whale is a freeware web browser developed by Naver Corporation. The browser is based on Chromium since its inception in 2011 and therefore Google Chrome apps are also compatible with the browser. The Naver Whale browser also has its own extensions that can be accessed through the Whale Store. Whale Browser is accessible through client desktop software and mobile apps. It is one of web browsers for Korea and quickly becoming the most popular and most used browser in the region.

Naver Whale for Windows 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 Naver.


Fortinet reported the vulnerability to Naver on October 10, 2017.

Naver confirmed the vulnerability on October 12, 2017.

Naver released patch for it on November 28, 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.