Zero-Day Advisory

Fortinet Discovers Swisscom TVMediaHelper DLL Preloading Vulnerability

Summary

Fortinet's FortiGuard Labs has discovered a DLL preloading vulnerability in Swisscom's TVMediaHelper for Windows.

Swisscom's TVMediaHelper for Windows is a desktop application using which users can enjoy photos and music that they have shared on their computer (Windows PC) via Swisscom TV.

Swisscom's TVMediaHelper 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.


Solutions

Users should remove the application from their system since it is a legacy application and no longer maintained by the vendor.

Timeline

Fortinet reported the vulnerability to Swisscom on June 15, 2017.

Swisscom confirmed the vulnerability on August 31, 2017.

Swisscom removed the vulnerable software on August 31, 2017.

Acknowledgement

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.