Russian military hackers target Ukraine with new MASEPIE malware

**Executive Summary:** Ukraine's CERT warns of a December 15–25, 2023 phishing campaign attributed to APT28 that used malicious links to drop a Windows LNK that launches PowerShell to install a new Python downloader called MASEPIE, deploy PowerShell 'STEELHOOK' infostealers, and deploy an OCEANMAP C# backdoor using IMAP for stealthy C2; attackers established persistence via Startup folder and registry changes and used IMPACKET/SMBEXEC for rapid lateral movement, with tools reportedly deployed within an hour of compromise.