The Computer Emergency Response Team of Ukraine (CERT-UA) has warned of new targeted cyber attacks in the country using a backdoor called CABINETRAT. The activity, observed in September 2025, has been attributed to a threat cluster it tracks as UAC-0245. The agency said it spotted the attack following the discovery of software tools taking the form of XLL files, which refer to Microsoft Excel add-ins that are typically used to extend the functionality of Excel with custom functions. Further investigation has uncovered that the XLL files are distributed within ZIP archives shared on the Signal messaging app, disguised as a document concerning the detention of individuals who had attempted to cross the Ukrainian border. The XLL, once launched, is designed to create a number of executables…