The zero-day exploit deployed by the Winter Vivern APT group only requires that the target views a specially crafted message in a web browser

This week, ESET research described how the Winter Vivern APT group has been exploiting a zero-day XSS vulnerability in Roundcube Webmail servers to target European governmental entities and a think tank. ESET researchers uncovered the attacks on October 11th while monitoring Winter Vivern’s cyberespionage operations, which typically take aim at governments in Europe and Central Asia. They promptly reported the security loophole to the Roundcube team on October 12th, who released security updates for the vulnerability four days later.

The security flaw (CVE-2023-5631) can be exploited via specially crafted email messages. Organizations are strongly recommended to update their installations of Roundcube Webmail to the latest version post-haste.

Find out more in the video and in our blogpost.

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