PSIRT Advisories

FortiClient installer DLL Hijacking Vulnerability

Summary

Multiple unsafe search path vulnerabilities in FortiClient online installers may allow an attacker with control over the directory in which the installers reside to execute arbitrary code on the system via uploading malicious .dll files in that directory.

Affected Products

FortiClientOnlineInstaller.exe for FortiClient for Windows 6.0.5 and below (CVE-2019-5589)

FortiClientOnlineInstaller.exe for FortiClient for Windows 6.4.6 and below (CVE-2020-9290)

FortiClientVPNOnlineInstaller.exe for FortiClient VPN for Windows 6.4.6 and below (CVE-2020-9290)

FortiClientEMSOnlineInstaller.exe for FortiClient EMS 6.2.1 and below (CVE-2020-9287)

Solutions

CVE-2019-5589: Use FortiClient for Windows online installer 6.0.6 or above.

CVE-2020-9290: Use upcoming FortiClient for Windows online installer 6.4.7 or above and version 7.0.1 or above; and upcoming FortiClient VPN for Windows online installer 6.4.7 or above and version 7.0.1 or above.

CVE-2020-9287: Use FortiClient EMS online installer 6.2.2 or above.
Revision History:
05-16-2019 Initial version
3-09-2020 add CVE-2020-9290 and CVE-2020-9287

Acknowledgement

Fortinet is pleased to thank Independent security researcher Honc (honcbb@gmail.com)for reporting CVE-2019-5589 and CVE-2020-9290, Houjingyi (houjingyi647@gmail.com) for reporting CVE-2020-9290 and CVE-2020-9287, security researcher Eran Shimony from CyberArk Labs for reporting CVE-2020-9290 and independent researcher Ameen Basha for reporting CVE-2020-9290 under responsible disclosures.