Fortinet Discovers Cisco Immunet Installer DLL Preloading Vulnerability
Fortinet's FortiGuard Labs has discovered a DLL preloading vulnerability in Cisco Immunet installer.
Cisco Immunet is a free, cloud-based, community-driven antivirus application, using the ClamAV and its own engine. The software is complementary with existing antivirus software. The application claims to be fast and to provide up-to-date protection against threats. Virus signature files are stored in the cloud, not on individual computers, so update downloads are not required. Once a virus is detected and blocked for one user, all other Immunet users receive the same protection almost instantly.
Cisco Immunet installer 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 Cisco.
Fortinet reported the vulnerability to Cisco on June 30, 2017.
Cisco confirmed the vulnerability on July 19, 2017.
Cisco patched the vulnerability on November 15, 2017.