How to remove Cthulhu Stealer (Mac)

What is Cthulhu Stealer

Cthulhu Stealer is a sophisticated information-stealing malware targeting macOS systems, designed to extract sensitive data such as login credentials, cryptocurrency wallets, and personal account information. Written in Go, it masquerades as legitimate software applications like CleanMyMac or popular games, tricking users into downloading and executing the malicious code. Once installed, it collects system information, including macOS version, IP address, and hardware details, and then proceeds to extract browser cookies, Keychain passwords, and data from various cryptocurrency wallets and online accounts. This stolen data is transmitted to cybercriminals who can use it for identity theft, unauthorized financial transactions, and further exploitation or sale on the dark web. Users may notice unfamiliar applications running on their system and experience degraded performance as a result of the malware’s activities. The financial and personal risks associated with Cthulhu Stealer are significant, making it imperative for users to implement robust security measures and promptly remove any detected infections.

How Cthulhu Stealer infected your system

Cthulhu Stealer is a sophisticated piece of malware designed to infiltrate macOS systems by disguising itself as a legitimate application within a DMG (Apple Disk Image) file. Commonly, these DMG files are masqueraded as popular software or game installers like CleanMyMac, Grand Theft Auto IV, or Adobe GenP. Once the user downloads and opens the fake DMG file, they are prompted to enter their system password, which grants the malware necessary permissions to execute its payload. Additionally, the malware may request specific application passwords, such as those for MetaMask, under the guise of legitimate prompts. Once installed, Cthulhu Stealer systematically scans the infected system for a variety of sensitive information, including login credentials, cryptocurrency wallets, and other personal data, which it then transmits to cybercriminals. This intricate method of infection highlights the importance of downloading software exclusively from official and reputable sources to minimize the risk of such harmful intrusions.

Remove Cthulhu Stealer from macOS manually

Removing Cthulhu Stealer from macOS requires a systematic approach that involves a combination of built-in tools, safe computing practices, and sometimes third-party software. Here’s a comprehensive guide to identifying and removing viruses from your Mac, ensuring your system’s integrity and security.

Step 1: Disconnect from the Internet

1. Disconnect your Mac from the Internet. This prevents the virus from sending data to its creator or downloading more malicious software. Turn off Wi-Fi and unplug any Ethernet cables.

Step 2: Enter Safe Mode

2. Restart your Mac in Safe Mode. Safe Mode performs a check of your startup disk and restricts certain software from automatically loading or opening.
   • For Intel-based Macs: Restart your Mac and immediately press and hold the Shift key until you see the login window.
   • For Apple Silicon Macs: Turn off your Mac, press and hold the power button until you see the startup options window, select your startup disk, press and hold the Shift key, then click Continue in Safe Mode.

Step 3: Use Built-in Tools for Malware Removal

3. Use Finder to identify and remove suspicious applications.
   • Open Finder, go to the Applications folder, and look for any applications you don’t recognize or didn’t intentionally download.
   • Right-click the suspicious application and select Move to Trash, then empty the Trash.
4. Use macOS built-in malware removal tool (MRT). macOS automatically runs MRT in the background, but you can manually run a malware scan by updating your software.
   • Go to System Preferences > Software Update.
   • Install any available updates, as these often include the latest security improvements and malware definitions.

Step 4: Check and remove Cthulhu Stealer from Login Items

Note: Cthulhu Stealer may set up to start on macOS startup. Therefore, before starting the removal, perform these steps:

1. Open System Preferences, choose Users & Groups.
2. Choose your account (set up as Current User).
3. Click Login Items tab.
4. Find suspicious entries. Select it, and click the “-“ (minus) button to remove them.

Step 5: Check and remove Cthulhu Stealer Malicious Device Profile

Important update: Cthulhu Stealer can install malicious Device Profile called AdminPrefs or similarly on MacOS, that won’t allow users to make changes to browser search engine and homepage settings. Follow instructions below to remove this profile.

Remove Cthulhu Stealer profile

1. Go to System Preferences and click on Profiles.
2. In the list of profiles on the left side, choose AdminPrefs or other profile and click on “-” button to remove it.
3. In your case it can be named differently, in this case remove all visible profiles. Check the picture below to see how it looks like.

Step 6: Reset Your Web Browsers

Reset Safari:

1. Start Safari on your Mac, click Safari to open drop-down menu and choose Preferences
2. Go to the Privacy section of Safari’s preferences.
3. Click Remove All Website Data button.
4. In the opened window, click Remove Now button to remove data stored by websites in Safari.
5. Go to the Advanced section of Safari’s preferences.
6. Click the Show Develop menu in menu bar option.
7. In the menu, click Develop and select Empty Caches from this menu.
8. Again, go to Safari menu and choose Clear History….
9. Choose to clear all history and click Clear History button.

Reset Google Chrome:

1. Start Google Chrome browser
2. In address box type (or copy-paste) chrome://settings.
3. Scroll down and find Show advanced settings link.
4. Click on it and scroll down to the bottom again.
5. Click Reset settings button and click Reset to confirm.

Reset Mozilla Firefox:

1. Start Mozilla Firefox browser.
2. In address box type (or copy-paste) about:support.
3. Click Refresh Firefox… button.
4. Click Refresh Firefox to confirm.

Step 7: Restore from a Backup

8. If the issue persists, consider restoring your Mac from a backup.
   • Use Time Machine or another backup system to restore your Mac to a state before it was infected.
   • Ensure the backup you choose predates the malware infection.

Prevention Tips

• Keep your macOS updated. Regularly check for and install macOS updates to ensure you have the latest security patches.
• Be cautious with downloads and attachments. Only download software from trusted sources like the Mac App Store or official websites.
• Use strong passwords and enable two-factor authentication (2FA) where possible.
• Consider enabling the macOS firewall in System Preferences > Security & Privacy.
• Regularly back up your Mac using Time Machine or another backup solution to ensure you can recover your system if needed.

Following these steps should help you remove most viruses from your Mac. If you continue to experience issues, consider seeking help from Apple Support or a professional cybersecurity service.