MacOS Malware Poses as Adobe Zii, Steals Credit Card Info and Mines Koto Cryptocurrency

February 04, 2019

By Luis Magisa

We've seen a diverse range of methods cybercriminals use to trick potential victims, but this one is certainly unusual. Our latest analysis revealed that even illegal cracking software programs are being taken advantage of by cybercriminals to lure users into installing malicious apps. In this particular case, we found a malicious app posing as Adobe Zii (a tool used to crack Adobe products) targeting macOS systems to mine cryptocurrency and steal credit card information.

Technical Analysis

The malicious app, which was sourced from VirusTotal and first reported by Malwarebytes, arrives in the target system as “Adobe Zii.app.”

Figure 1. The content of Adobe Zii.app

When executed, it uses the automator.app to launch Bash script codes found in Adobe Zii.app\Contents\document.wflow.

Figure 2. Malware launching Bash script codes

While running a copy of Adobe Zii.app, we observed that it downloads sample.app from hxxp://46[.]226[.]108[.]171:80/sample.zip and saves it to the user directory ~/. The contents are then extracted and executed in the system. This is the original Adobe Zii.app used to camouflage its malicious background activities.

We also found out that the malware connects to hxxps://ptpb.pw/jj9a, which contains an encrypted Python script that checks if Little Snitch — a host-based application firewall for macOS — is running. If it’s not, the script will connect to hxxp://46[.]226[.]108[.]171:4444/login/process.php, which hosts an encrypted Empyre backend capable of pushing arbitrary commands to an infected macOS system. It will receive a command to download Bash scripts from hxxp://46[.]226[.]108[.]171:4444/uploadminer[.]sh once the backdoor runs. The file uploadminer.sh will be saved to the system and executed.

MacOS Malware Steals Credit Card Info

uploadminer.sh contains routines capable of stealing saved information from Google Chrome browsers. Target information includes origin URL, username, password, and credit card name, number, and expiration date.

Figure 3. Malware stealing user credentials and credit card information

The malware connects to hxxp://46[.]226[.]108[.]171/harmlesslittlecode[.]py and saves Python scripts to ~/Library/Application Support/Google/Chrome/Default. This will be used to display the decrypted information from the Google Chrome browser. The information will then be collected as a .txt file and .zip-compressed along with Google Chrome cookies. This will be saved as ~/Library/Application Support/Google/Chrome/Default/{username}.zip, and subsequently uploaded to hxxp://46[.]226[.]108[.]171:8000.

Autostart Technique and Cryptocurrency-Mining

The malware also downloads a plist file from hxxp://46[.]226[.]108[.]171/com[.]apple[.]rig2[.]plist and saves it to ~/Library/LaunchAgents. The plist file will be used to launch xmrig2 to mine cryptocurrency. It also downloads a plist file from hxxp://46[.]226[.]108[.]171/com[.]apple[.]proxy[.]initialize[.]plist, which contains encrypted Python commands identical to the one that checks if Little Snitch is running and connects to the encrypted Empyre backend. These plist files are loaded into the system through the launchctl command, enabling them to run at startup.

The malware connects to hxxp://46[.]226[.]108[.]171/xmrig2 and saves a file to /Users/Shared/xmrig2 to mine cryptocurrency. The saved file is a commandline app used to mine Koto in particular.

Figure 4. The entry in the script which contains the cryptocurrency-mining command

The following credentials will be used to mine cryptocurrency on the infected system:

Trend Micro Solutions

MacOS users can stay safe from such threats by regularly updating the system and applications to patch exploitable vulnerabilities. Additionally, downloading software and applications from official websites and trusted app stores can protect against threats that pose as legitimate programs.

MacOS users can also benefit from security solutions such as Trend Micro Home Security for Mac, which provides comprehensive security and multi-device protection against cyberthreats. Enterprises can benefit from Trend Micro’s Smart Protection Suites with XGen™ security, which infuses high-fidelity machine learning into a blend of threat protection techniques to eliminate security gaps across any user activity and endpoint.

Indicators of Compromise (IoCs)

Files	Detection Names	SHA256s
Adobe Zii.app.zip	Coinminer.MacOS.MALXMR.A	ebecdeac53069c9db1207b2e0d1110a73bc2 89e31b0d3261d903163ca4b1e31e
document.wflow	Coinminer.MacOS.MALXMR.A	7b90fe8aec599625dd7d4ce0026f839c16fc 12aa11839a88055cf49a6db9529b
uploadminer.sh	Coinminer.SH.MALXMR.A	6236f77899cea6c32baf0032319353bddfec af088d20a4b45b855a320ba41e93
com.proxy.initialize.plist	Coinminer.MacOS.MALXMR.A	cdb2fb9c8e84f0140824403ec32a2431fb35 7cd0f184c1790152834cc3ad3c1b
com.apple.rig2.plist	Coinminer.MacOS.MALXMR.A	91b3f5e5d3b4e669a49d9c4fc044d0025cab b8ebb08f8d1839b887156ae0d6dd
harmlesslittlecode.py	Coinminer.Python.MALXMR.A	7bc657c96c15ec0629740e00a9c7497417b 599694c6b7598eeff095136cbd507
xmrig2	Coinminer.MacOS.MALXMR.A	ede858683267c61e710e367993f5e589fcb4 b4b57b09d023a67ea63084c54a05

Updated: February 11, 2019 10:40 AM

Based on a more in-depth analysis, we found out that the cryptocurrency mined was Koto and not Monero. We changed Monero to Koto to reflect this correction.

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Posted in Cybercrime & Digital Threats, Cryptocurrency-mining, Malware, Mac OS