A new wave of spam email has prompted antivirus companies to issue a warning about emails infected with Nemucod malware. The emails are rapidly spreading around the globe, with Japan currently the worst hit; however, the prevalence of infected spam email is also particularly high in Europe, Australia, Canada, and the United States.
Nemucod Malware Used to Infect Devices with Teslacrypt and Locky Ransomware
Nemucod malware is a Trojan downloader that is used to install a payload of ransomware. Currently Nemucod malware is being spread via spam email and is being used to download Locky and Teslacrypt ransomware onto the devices of anyone who opens the infected email attachments.
In contrast to many malware-infected emails which contain numerous grammatical and spelling mistakes, the emails being used to spread this nasty malware are well written and convincing. The emails claim the attachment is an invoice or an official document such as a notice requiring the target to appear in court.
As we have previously reported, Teslacrypt and Locky ransomware are particularly nasty ransomware. On download they search the user’s computer for a wide variety of file types and lock all of those files with powerful encryption. They will also search for files on attached portable storage devices, virtual devices, and network drives. Locky is also capable of removing volume shadow copies (VSS) making it impossible for infected users to restore their devices to a point before the ransomware infection.
Documents, images, spreadsheets, system files, and data backups are all encrypted. Locky has been programmed to encrypts hundreds of file types. Fortunately, there are a number of steps that can be taken to prevent malware and ransomware infections.
How to Prevent a Ransomware Infection
Steps can be taken to reduce the risk of ransomware being installed, but even the best defenses can be breached. It is therefore also essential to ensure that all critical data files are backed up regularly. If a daily backup is performed, at worst, an organization should only lose a maximum of 24 hours of data.
It is essential that once backups are made, the drive uses to store the backup files is disconnected. Some ransomware variants are capable of scanning network drives and can encrypt backup files on connected backup devices.
Simply receiving a malicious spam email that has been infected with malware will not result in a device being infected. A device will only be infected if an end user opens the infected attachment.
The best way to defend against ransomware is never to open email attachments that have been sent from unknown individuals. While this is straightforward for individual users, for businesses it is harder to ensure that no member of staff will be fooled into opening an infected email attachment.
It is therefore essential to provide all members of staff with security training to ensure they are aware about best practices to adopt to reduce the risk of installing ransomware. However, all it takes is for one member of staff to open a malicious email attachment for the network to be infected. For peace of mind, a robust spam filtering solution for businesses should be implemented. SpamTitan blocks 99.9% of all spam email, drastically reducing the risk of ransomware and other malicious emails from being delivered to end users.