Adobe has released an unscheduled update to correct vulnerabilities in Adobe Flash Player, including a zero-day flaw that is currently being targeted in the wild by an APT threat group on targets in Russia. One target was a Russian healthcare center that supplies medical and cosmetic surgery services to high level civil servants of the Russian Federation.

The zero-day flaw is a use-after-free weakness – CVE-2018-15982 – which enables arbitrary code execution and privilege execution in Flash Player. A malicious Flash object operates malicious code on a victim’s computer which gives command line access to the system.

The vulnerability was noticed by security researchers at Gigamon ATR who reported the vulnerability to Adobe on November 29. Researchers at Qihoo 360 discovered a spear phishing campaign that is being used to send a malicious document and linked files that exploit the weakness. The document used in the campaign was a forged staff questionnaire.

The emails included a .rar compressed file attachment which included a Word document, the vulnerability, and the payload. If the .rar file is unpacked and the document viewed, the user is shown a warning that the document may damage the computer. If the content is activated, a malicious command is run which extracts and initiates the payload – a Windows executable file named backup.exe that is hidden as an NVIDIA Control Panel application. Backup.exe acts as a backdoor into a system. The malicious payload gathers system data which is sent back to the hackers via HTTP POST. The payload also downloads and runs shell code on the infected device.

Qihoo 360 researchers have labelled the campaign Operation Poison Needles due to the identified target being a healthcare center. While the attack seems to be politically motivated and highly targeted, now that details of the vulnerability have been made public it is likely that other threat groups will use exploits for the vulnerability in more and more attacks.

It is therefore vital for companies that have Flash Player installed on some of their devices to update to the most recent version of the software as soon as they can. That said, removing Flash Player, if it is not required, is a better option given the number of vulnerabilities that are identified in the software each month.

The vulnerability is Flash Player 31.0.0.153 and all previous versions. Adobe has addressed the flaw together with a DLL hijacking vulnerability in version 32.0.0.101.