China-Linked APT GopherWhisper Abuses Legitimate Services in Government Attacks

Summary

ESET uncovered a previously unknown China-linked APT group called GopherWhisper, active since at least November 2023, that uses multiple Go-based backdoors (LaxGopher, RatGopher, BoxOfFriends) alongside custom loaders and injectors to target government entities. The group abuses legitimate services including Slack, Discord, Microsoft Graph API, and file.io for command-and-control communication and data exfiltration. The investigation began with a backdoor found on Mongolian government systems in January 2025, leading to the discovery of approximately 12 infected machines within that organization, with evidence suggesting dozens of additional victims worldwide.

Full text

A newly uncovered APT is relying on legitimate services for command-and-control (C&C) communication and data exfiltration, ESET warns. Tracked as GopherWhisper (PDF) and active since at least November 2023, the hacking group is operating out of China, as timestamp inspection of chat messages and emails has revealed. The APT came to the spotlight in January 2025, during the investigation into a Go-based backdoor found on the systems of a governmental entity in Mongolia, which led to the identification of several other backdoors, custom loaders, and injectors associated with the group. Dubbed LaxGopher, the backdoor uses Slack for C&C communication and can execute commands via command prompt, exfiltrate victim data, and fetch and execute additional payloads on the infected machines. GopherWhisper, ESET says, mainly used LaxGopher to enumerate drives and files. An injector named JabGopher is used to execute the backdoor in the memory of a newly spawned instance of svchost.exe. One of the tools that LaxGopher can deploy is CompactGopher, a file collector written in Go that can compress files from the command line and send them to the file.io file-sharing service using a public REST API.Advertisement. Scroll to continue reading. Another tool in GopherWhisper’s arsenal is RatGopher, a Go-based backdoor. Unlike LaxGopher, it uses Discord for C&C communication. It can open new instances of the command prompt and upload or download files from file.io. The APT also relies on a C++ backdoor called SSLORDoor, which uses OpenSSL BIO for communication via raw TCP sockets. The malware can spawn a hidden command prompt process, enumerate drives, execute commands related to file manipulation, and create new socket connections. ESET’s investigation uncovered two additional tools that GopherWhisper deployed against the same Mongolian government organization, namely the BoxOfFriends Go backdoor that relies on the Microsoft Graph API for communication via draft Outlook messages, and the FriendDelivery DLL injector that loads it. The BoxOfFriends backdoor can exfiltrate files, manipulate ports, and execute supplied commands through a shell opened on the host. The China-linked APT infected roughly 12 systems within the victim Mongolian governmental institution. According to ESET, dozens of other victims were likely targeted as well. “Due to the lack of similarities in code, TTPs, and targeting to any existing APT group, we have created GopherWhisper as a new group and attribute the described toolset to it,” ESET notes. Related: US Federal Agency’s Cisco Firewall Infected With ‘Firestarter’ Backdoor Related: Trump Administration Vows Crackdown on Chinese Companies ‘Exploiting’ AI Models Made in US Related: Chinese Cybersecurity Firm’s AI Hacking Claims Draw Comparisons to Claude Mythos Related: New Wiper Malware Targeted Venezuelan Energy Sector Prior to US Intervention Written By Ionut Arghire Ionut Arghire is an international correspondent for SecurityWeek. More from Ionut Arghire Alleged Chinese State Hacker Extradited to USDozens of Open VSX Extension Clones Linked to GlassWorm MalwareNo Patch for New PhantomRPC Privilege Escalation Technique in WindowsSpectrum Security Emerges From Stealth Mode With $19 MillionIncomplete Windows Patch Opens Door to Zero-Click AttacksOpenSSH Flaw Allowing Full Root Shell Access Lurked for 15 YearsUNC6692 Uses Email Bombing, Social Engineering to Deploy ‘Snow’ MalwareEasily Exploitable ‘Pack2TheRoot’ Linux Vulnerability Leads to Root Access Latest News Sandhills Medical Says Ransomware Breach Affects 170,000Fresh LiteLLM Vulnerability Exploited Shortly After DisclosureHundreds of Internet-Facing VNC Servers Expose ICS/OTCheckmarx Confirms Data Stolen in Supply Chain AttackIranian Cyber Group Handala Targets US Troops in Bahrain38 Vulnerabilities Found in OpenEMR Medical SoftwareChrome 147, Firefox 150 Security Updates Rolling OutCritical GitHub Vulnerability Exposed Millions of Repositories Trending Daily Briefing Newsletter Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts. Webinar: A Step-by-Step Approach to AI Governance April 28, 2026 With "Shadow AI" usage becoming prevalent in organizations, learn how to balance the need for rapid experimentation with the rigorous controls required for enterprise-grade deployment. Register Virtual Event: Threat Detection and Incident Response Summit May 20, 2026 Delve into big-picture strategies to reduce attack surfaces, improve patch management, conduct post-incident forensics, and tools and tricks needed in a modern organization. Register People on the MoveMongoDB has appointed Doug Bowers as Chief Information Security Officer.Ben Wilkens has been promoted to Director of Cybersecurity at NMFTA.Cato Networks has appointed Meital Koren as Chief Legal Officer.More People On The MoveExpert Insights The Mythos Moment: Enterprises Must Fight Agents with Agents Only with the right platform and an agentic, AI-driven defense, will enterprises be able to protect themselves in the agentic era. (Etay Maor) Why Cybersecurity Must Rethink Defense in the Age of Autonomous Agents From autonomous code generation to decision-making systems that initiate actions without human intervention, the industry is entering a new phase. (Torsten George) Government Can’t Win the Cyber War Without the Private Sector Securing national resilience now depends on faster, deeper partnerships with the private sector. (Steve Durbin) The Hidden ROI of Visibility: Better Decisions, Better Behavior, Better Security Beyond monitoring and compliance, visibility acts as a powerful deterrent, shaping user behavior, improving collaboration, and enabling more accurate, data-driven security decisions. (Joshua Goldfarb) The New Rules of Engagement: Matching Agentic Attack Speed The cybersecurity response to AI-enabled nation-state threats cannot be incremental. It must be architectural. (Nadir Izrael) Flipboard Reddit Whatsapp Whatsapp Email

Indicators of Compromise

• malware — LaxGopher
• malware — RatGopher
• malware — CompactGopher
• malware — BoxOfFriends
• malware — JabGopher
• malware — FriendDelivery
• malware — SSLORDoor

Entities