Another New Attack Vector for Ransomware
April 11th, 2018
It has been awhile since Microsoft Windows has had a vulnerability that affects all versions, and with a successful exploit could completely own a system just by visiting a malicious website. In such an attack, there is no code to download nor files to run; just visiting a malicious site is all it will take for a threat actor to have full control of your desktop or server.
As a part of Microsoft’s April 2018 Patch Tuesday release, new security updates have been released to prevent the scenario above from becoming a reality. All customers should be keenly aware of the ramifications, especially considering what we learned with regard to ransomware in Verizon’s 2018 DBIR.
These newly-released patches should have the highest priority for installation across all desktops and servers because all it will take is an email that auto-renders in a browser or a compromised website to conduct the attack. Odds are, the payload will be ransomware but, technically, any malware can be delivered using this vulnerability and exploit combination. It will be difficult for endpoint protection products to defend against this threat even with sandboxing and application control. Attackers do not need to drop a local file in order for successful exploitation to occur. Trusted Microsoft commands can be leveraged to bypass these security controls.
As a matter of detail, all five of these vulnerabilities are in the Windows Graphics Components and are due to the improper handling of embedded fonts by the Windows Font Library that can cause remote code execution. They were discovered by Hossein Lotfi at Flexera Software and have the following CVE’s: CVE-2018-1010, CVE-2018-1012, CVE-2018-1013, CVE-2018-1015, and CVE-2018-1016.
In order to detect these flaws, Retina customers should make sure they are running Audit Revision 3392 or higher and have audit IDs enabled:
- 68401 – Microsoft Security Update for Windows – Apr 2018 – 8.1/2012R2
- 68402 – Microsoft Security Update for Windows – Apr 2018 – 7/2008R2
- 68403 – Microsoft Security Update for Windows – Apr 2018 –2012
- 68454 – Microsoft Cumulative Security Update for Windows 10 – Apr 2018
- 68466 – Microsoft Security Update for Windows – Apr 2018 – 2008 – 4093223 Front Library
- 68470 – Microsoft Security Update for Windows – Apr 2018 – 2008 – 4093257
- 68473 – Microsoft Security Update for Windows – Apr 2018 – 2008 – 4093478 Kernel
And, as a security best practice, patch these as soon as possible. While these flaws are not as critical as EternalBlue (the vulnerability behind WannaCry) they can be blended with other vulnerabilities and exploits to allow lateral movement and credential scraping that could have just as dire results. It is not all doom and gloom, but this patch release has the potential to be something really bad in the future.