Winter Vivern

Winter Vivern, a malicious threat actor, has been identified as the entity behind recent cyberattacks targeting several European government organizations. The group exploited a zero-day vulnerability in the Roundcube webmail software, using it to launch their offensive operations. This advanced persistent threat (APT) group is linked to Russia and is known for its cyberespionage activities, with targets including not only government entities but also military and national infrastructure-related bodies across Europe. The first notable attack by Winter Vivern was reported in October 2023 by ESET Research. They revealed that the group had exploited a similar vulnerability within the Roundcube webmail software, specifically an XSS (Cross-Site Scripting) vulnerability. This allowed them to successfully target various European government entities, marking the beginning of their malicious campaign. Most recently, Recorded Future's Insikt Group reported another major attack from Winter Vivern. Once again, the group leveraged an XSS vulnerability in the Roundcube software, broadening their target range to include Ukraine, Poland, and Georgia. These attacks underscore the ongoing threat posed by Winter Vivern and highlight the need for robust cybersecurity measures to counter such sophisticated APT groups.