Xbash malware is one of several new malware threats to be detected in recent weeks that incorporate the file-encrypting properties of ransomware with the coin mining functionality of cryptocurrency mining malware.
This year, several cybersecurity and threat intelligence companies have reported that ransomware attacks have plateaued or are in decline. Ransomware attacks are still profitable, although it is possible to make more money through cryptocurrency mining.
The recent Internet Organized Crime Threat Report released by Europol notes that cryptojacking is a new cybercrime trend and is now a regular, low-risk revenue stream for cybercriminals, but that “ransomware remains the key malware threat”. Europol notes in its report that a decline has been seen in random attacks via spam email, instead cybercriminals are concentrating on attacking businesses where greater profits lie. Those attacks are highly targeted.
Another emerging trend offers cybercriminals the best of both worlds – the use of versatile malware that have the properties of both ransomware and cryptocurrency miners. These highly versatile malware variants provide cybercriminals with the opportunity to obtain ransom payments as well as the ability to mine for cryptocurrency. If the malware is installed on a system that is not ideally suited for mining cryptocurrency, the ransomware function is activated and vice versa.
Xbash malware is one such threat, albeit with one major caveat. Xbash malware does not have the ability to restore files. In that respect it is closer to NotPetya than Cerber. As was the case with NotPetya, Xbash malware just masquerades as ransomware and demands a payment to restore files – Currently 0.2 BTC ($127). Payment of the ransom will not result in keys being supplied to unlock encrypted files, as currently files are not encrypted. The malware simply deletes MySQL, PostgreSQL, and MongoDB databases. This function is activated if the malware is installed on a Linux system. If it is installed on Windows devices, the cryptojacking function is activated.
Xbash malware also has the ability to self-propagate. Once installed on a Windows system it will spread throughout the network by exploiting vulnerabilities in Hadoop, ActiveMQ and Redis services.
Xbash malware is written in Python and compiled into a portable executable (PE) format using PyInstaller. The malware will run its file encrypting/deletion routine on Linux systems and use JavaScript or VBScript to download and run a coinminer on Windows systems. Palo Alto Networks’ Unit42 has attributed the malware to a threat group known as Iron Group, which has previously been associated with ransomware attacks.
Currently, infection occurs through the exploitation of unpatched vulnerabilities and brute force attacks on systems with weak passwords and unprotected services. Protection against this threat requires the use of strong, unique non-default passwords, prompt patching, and endpoint security solutions. Blocking access to unknown hosts on the Internet will prevent communication with its C2 if it is installed, and naturally it is essential that multiple backups are regularly made to ensure file recovery is possible.
Kaspersky Lab determined there has been a doubling of these multi-purpose remote access tools over the past 18 months and their popularity is likely to continue to increase. This type of versatile malware could well prove to be the malware of choice for advanced threat actors over the course of the next 12 months.