Fortinet Discovers Synology Assistant DLL Preloading Vulnerability
Fortinet's FortiGuard Labs has discovered a DLL preloading vulnerability in Synology Assistant.
Synology Assistant is an easy tool to manage Synology NAS(s) in local area network (LAN), especially when you have multiple machines working within LAN. With Synology Assistant, you can install DSM, share printers, set up WOL and upload photos.
Synology Assistant before 6.1-15163 is susceptible to multiple DLL preloading vulnerabilities. The issue occurs when the application looks to load a DLL for execution and loads an attacker provided malicious DLL instead of the legitimate DLL. 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 (located in the current working directory) running under the context of the application.
Users should apply the solution provided by Synology.
Fortinet reported the vulnerability to Synology on July 7, 2017.
Synology released patch for it on August 16, 2017.
This vulnerability was discovered by Kushal Arvind Shah of Fortinet's FortiGuard Labs.