Security Advisories

FSC-2017-3: Memory data disclosure


F-Secure Internet Gatekeeper returns random memory data when the HTTP GET requests are too long.

Affected Products

  • Risk Level (Low/Medium/High/Cricital) High
  • F-Secure Internet Gatekeeper 5.50 and below
  • F-Secure Internet Gatekeeper Virtual Appliance and below


  • Risk Level (Low/Medium/High/Cricital) High
  • All supported platforms for the affected products

More Information

A vulnerability was discovered in F-Secure Internet Gatekeeper whereby the proxy server returns random memory data as part of the response when the HTTP GET requests contains a long path. The exploit can be triggered both locally and remotely by an attacker. A successful attack will result in the attacker gaining access to random proxy server data mixed with intended response text.

This issue was reported to F-Secure through the Vulnerability Reward Program. No known exploit or attack has been seen in the wild.

Mitigating Factors

HTTP proxy option has to be turned on for a successful exploitation. Furthermore, HTTPS connection is not vulnerable to this attack.

Fix Available

Product Versions Download
F-Secure Internet Gatekeeper

5.40 - 5.50

Hotfix 4:


Security hotfix is only released for version 5.40 – 5.50, as per our Support Policy. Users with older versions are advised to upgrade to a newer version which has security hotfixes support.

F-Secure Internet Gatekeeper Virtual Appliance
  1. Download and re-install the latest version of the appliance from
  2. Verify the latest appliance version by opening the management console and checking the full version shown in the login screen:
    1. IGK VA:


F-Secure Corporation would like to thank Juho Nurminen for bringing this issue to our attention.

Date Issued: 2017-11-29