Zero-Day Advisory

Fortinet Discovers Yandex Direct Commander DLL Preloading Vulnerability

Summary

Fortinet's FortiGuard Labs has discovered a DLL preloading vulnerability in Yandex Direct Commander.

Yandex Direct Commander is a professional ad management program in Yandex.Direct that users can use without accessing the web interface. Direct Commander allows users to easily find one ad among hundreds or one keyword among thousands, even if they relate to different campaigns. It allows users to make changes quickly using mass editing tools: copy and move campaigns, groups, ads, and keywords; delete keyword overlaps and duplicates; deftly manage bids, etc. and also create campaigns just by uploading ads and keywords from files in any format.

Yandex Direct Commander 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 apply the solution provided by Yandex.

Timeline

Fortinet reported the vulnerability to Yandex on June 30, 2017.

Yandex confirmed the vulnerability on July 4, 2017.

Yandex patched the vulnerability on July 4, 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.