As was previously covered in this blog, ransomware attacks are a significant threat to organisations as they can lock down systems and hold data for ransom. To add insult to injury, these kinds of threats are usually deployed with other malware, including Emotet and Trickbot, to launch widespread ransomware attacks that can cripple an entire enterprise network.
Emotet spreads through targeted phishing emails with attackers posing as a legitimate user known to the victim – usually a coworker, manager or client. These emails appear to contain important documents like invoices or agreements which a user is prompted to open; in actuality, these contain infected attachments which download Emotet upon being viewed.
Once Emotet has taken control of the victim’s machine, it can then propagate itself to other users in the victim’s contact list using these same phishing tactics. Because these emails are sent from a legitimate user’s email that has been taken over by the threat actor, recipients are often unaware that these contain a malicious attachment. Recent variations of Emotet can even hijack previous email conversations by replying to these, further convincing the recipient that these emails are legitimate. All it takes is for the user to open an infected document and enable macros for Emotet to spread. A Powershell command or a heavily obfuscated JavaScript downloader will execute that downloads Emotet from malicious domains. Emotet can then communicate with a remote C2 server to download the Trickbot trojan that steals user credentials and banking details.
Emotet is persistent. It injects its code into running services and alters registry entries ensuring that it cannot be removed, even by antivirus software. It can also spread throughout an entire corporate network by brute-forcing credentials, and Trickbot can spread further by taking advantage of the EternalBlue vulnerability that is present on Windows machines. Once Emotet and Trickbot have taken over a corporate network, this serves as the initial attack vector for the Ryuk ransomware to take over every connected machine and hold data for ransom. These kinds of attacks are sophisticated campaigns that utilise several kinds of malware, potentially costing an organisation millions of dollars.
In January 2020, the United Nations was even a target in an Emotet spear-phishing campaign. The attackers purported to be representatives from the Permanent Mission of Norway, sending targeted phishing emails to over 600 United Nations staffers. The emails stated that there was an issue with a signed agreement, and the recipient had to review the attached document to find out what it was. Although the attackers could have chosen to make their approach more unique to succeed in fooling the United Nations employees, the attached word document contained a downloader for Emotet as was seen in previous attacks. Fortunately, no victims of this campaign have been reported from the time that this was written.
With an organisation as large as the United Nations being targeted by these threats, no business is safe. Contact Gridware if you would like to find out how to protect yourself from these threats.
