Microsoft is urging administrators of self-hosted Minecraft servers to level up to the latest update to fight against Khonsari ransomware attacks exploiting the sensitive Log4Shell security vulnerability.
A Swedish video game developer aka Mojang Studios behind Minecraft, released an emergency security update last week to address the bug tracked as CVE-2021-44228 in the Apache Log4j Java logging library (utilized by the game’s Java Edition client and multiplayer servers).
There are no mentions of attacks targeting Minecraft servers utilizing Log4Shell exploits at this time; various security experts update their CVE-2021-44228 guidance today alert of the current exploitation to transmit the ransomware on non-Microsoft hosted Minecraft servers.
“In Such cases, an adversary sends a malicious in-game message to a vulnerable Minecraft servers, which exploits CVE-2021-44228 to fetch and run and attacker-hosted payload on both the server and on connected vulnerable clients,” Microsoft stated.
“We also observed exploitation leading to a malicious Java class file that is the Khonsari ransomware, which is then executed in the context of javaw.exe to ransom the system.” The Microsoft Threat Intelligence Center (MSTIC) also observed PowerShell-based reverse shells set up in enterprise seize where Log4j exploits targeting Minecraft servers were the entry point.
While Minecraft is not something one would expect to discover installed on an enterprise endpoint, the attackers who successfully negotiate one of these servers also utilized Mimikats to hijack credentials, likely to maintain access to the hijacked systems for follow-on activity.
Defend your Minecraft server from Log4Shell attacks
Microsoft warns all admins to immediately install the latest Minecraft server updates to defend them against these attacks and asks players to only connect to trusted Minecraft servers. If you are hosting your Minecraft: Java Edition server, you need to follow the procedure outlined here.
To upgrade to the patched version, gamers using Mojang’s official client are advised to close all running game and Minecraft Launcher instances and restart the Launcher to install the patch automatically. Those using modified Minecraft clients and third-party launchers should reach out to their third-party providers for a security update.
Is it Ransomware or the Wiper?
Khonsari, the malware strain set up in such attacks, we tagged as ransomware by Bitdefender, who was the first to spot it set up in Log4Shell attacks. However, as our experts reported, Khonsari’s ransomware operators pay a ransom. Moreover, Emsisoft analyst also pointed out that the ransomware is named after and utilizes contact information for a Louisiana antique shop owner rather than the attacker.
The lack of payment info would classify it as a destructive malware type known as a wiper, which allows taking down Minecraft servers for griefing or trolling purposes.
