WinRAR users on older version of software are warned of a new email exploit actively circulating in-the-wild

https://www.pcmag.com/news/366852/hackers-start-exploiting-serious-winrar-flaw-to-spread-malwa

WinRAR users need to watch out. Hackers are starting to exploit a newly disclosed bug in the file-archiving tool to secretly install malware on Windows PCs.  Chinese security firm Qihoo 360 has uncovered several file archive samples that exploit the WinRAR vulnerability to deliver malware to a victim’s computer. One of the attacks was sent over email.  The first sample was detected only two days after the WinRAR bug was publicly disclosed by a separate security firm, Check Point. The bug is particularly problematic because WinRAR claims to have over 500 million users. A hacker can exploit the vulnerability to craft seemingly benign RAR archive files that are actually malicious.

Possibly the first malware delivered through mail to exploit WinRAR vulnerability. The backdoor is generated by MSF and written to the global startup folder by WinRAR if UAC is turned off