Ukraine’s frontline cyber defense agency became the subject of its own investigation last week after an unknown threat actor built a convincing fake version of its website, sent emails impersonating its staff and instructed recipients across the country to download malware packaged as official security software.

The Computer Emergency Response Team of Ukraine, CERT-UA, disclosed on Sunday, that between March 26 and 27, attackers distributed emails falsely attributed to CERT-UA, urging recipients to download a password-protected archive named either “CERT_UA_protection_tool.zip” or “protection_tool.zip”. The file was made available for download from Files.fm file-sharing service and installed what the messages described as specialized protective software.

The phishing emails were targeted at a broad cross-section of Ukrainian institutions including government organizations, medical centers, security companies, educational institutions, financial institutions and software development firms.

Supporting the phishing campaign, attackers had registered and populated a counterfeit website at cert-ua[.]tech — a domain created on March 27, just one day into the distribution window. The look-a-like website had content lifted directly from the official CERT-UA website at cert[.]gov[.]ua, alongside fabricated instructions for downloading the malicious “protection tool.”

The executable file inside those archives was not protective software. CERT-UA classified it as AGEWHEEZE, a full-featured Remote Access Trojan (RAT) written in the Go programming language.

A RAT is malware that gives an attacker complete remote control over an infected machine: not just file access, but live screen viewing, keyboard and mouse emulation, command execution, process and service management, clipboard reading and writing, and the ability to shut down, restart, or lock the device entirely.

AGEWHEEZE’s command set is exhaustive and purpose-built for persistent, covert control. It supports screen capture and real-time input emulation, full file system operations including read, write, delete, rename, and directory creation, process killing, service control, autorun management, terminal access, and the ability to open arbitrary URLs on the victim machine.

AGEWHEEZE establishes persistence through the Windows registry startup key, the Startup directory, or a scheduled task, creating entries named “SvcHelper” or “CoreService” depending on the infection path. All communications to its command-and-control server route over WebSocket connections to a server hosted on infrastructure belonging to French cloud provider OVH.

That command-and-control server carried its own revealing details. On port 8443, a web page titled “The Cult” displayed an authentication form. Buried in the HTML source of that page, investigators found Russian-language text reading: “Membership suspended. Your access to the Cult has been blocked. Contact the administrator to restore it.” The self-signed SSL certificate on the server was created on March 18, with “TVisor” listed in the Organization field, matching the internal package name found inside the malware itself: “/example.com/tvisor/agent.

Attribution arrived quickly and from the attackers themselves. A review of the AI-generated fake website at cert-ua[.]tech uncovered a line embedded in the HTML code reading: “With Love, CYBER SERP — https://t[.]me/CyberSerp_Official.”

On March 28, the day after the campaign launched, the Telegram channel referenced in that code published a message claiming responsibility for the attack, eliminating any ambiguity about attribution. CERT-UA created the tracking identifier UAC-0255 for this activity.

The agency assessed the cyberattack as “unsuccessful.” No more than a few personal devices belonging to employees of educational institutions were identified as infected. CERT-UA said its specialists provided methodological and practical assistance to affected parties, and acknowledged Ukrainian electronic communications providers for their contribution to delivering cyber threat information to subscribers and maintaining national cyber incident response infrastructure.

CERT-UA itself has previously documented campaigns by multiple threat groups — including UAC-0002, UAC-0035, and the group tracked here as UAC-0252 — that similarly weaponize government branding. In this case, the attackers targeted the cyber defense agency whose name carries the highest authority in Ukrainian information security communications, turning that trust directly against the institutions that rely on it.

CERT-UA noted that the development of artificial intelligence significantly simplifies the execution of cyber threats. The attackers’ own use of an AI-generated phishing site is a direct illustration of that warning, the cyber defense agency explained. It recommended that organizations reduce their attack surface by configuring standard operating system protections including Software Restriction Policies and AppLocker, and deploying specialized endpoint protection tools.

Full indicators of compromise including file hashes, network indicators, and host-based artifacts are available in the CERT-UA advisory.

Also read: Hackers Exploit RDP Tools to Breach Ukraine’s Notarial Offices, CERT-UA Reports