North Korean threat actors, potentially linked to the Lazarus Group, have expanded their tactics by embedding malware in macOS applications developed with Flutter, a cross-platform development framework. This marks a significant evolution in their attack strategies, as the malware is delivered within a seemingly innocent Minesweeper game titled “New Updates in Crypto Exchange (2024-08-28).” The game is a clone of a publicly available iOS game hosted on GitHub, illustrating the hackers’ use of familiar, low-profile applications to lure victims. This tactic could signal a new phase in North Korean cyber operations, with malware hidden inside legitimate-looking apps to avoid detection.
The apps were signed and notarized with legitimate Apple developer IDs, including those from the Baltimore Jewish Council and the Fairbanks Curling Club, which allowed them to bypass Apple’s security processes. However, these certificates were later revoked by Apple once the threat was identified. This step highlights the hackers’ ability to circumvent common security measures and underscores the risks associated with trusting notarized apps from unverified sources. Upon installation, the malware communicates with a remote server, downloading and executing malicious AppleScript code, which could further compromise the device.
In addition to the Flutter-based malware, variants written in Go and Python were also found, indicating that North Korean actors are using a multi-language approach in their attacks. These additional variants, named “NewEra for Stablecoins and DeFi” and “CeFi (Protected).app,” share similar functionality to the Flutter app, including the ability to run AppleScript payloads received from a server. This diversification in malware development suggests that the attackers are refining their tools to avoid detection and increase the chances of successful infiltration.
The discovery of this malware is part of a broader trend of North Korean hackers targeting cryptocurrency and decentralized finance companies, which have become a prime focus for the country’s cyber espionage efforts. The use of game-themed lures, the ability to bypass Apple’s notarization system, and the continuous development of malware variants all point to a highly adaptable and persistent threat actor. These developments emphasize the need for organizations, particularly in the cryptocurrency sector, to remain vigilant and employ advanced detection and defense strategies to combat such sophisticated threats.
