Top 10 Malware March 2018

March saw increases across the board in notifications, driven by a continued elevation in Kovter activity and an Emotet outbreak. This led to an almost 47% increase in Top 10 activity, as well as a 32% increase in total malware.

Every month the MS-ISAC maps the Top 10 Malware observed from monitoring state and local networks to common infection vectors. This is done by using open source observations and reports on each malware type. March's increase in across vectors coincided with the general increase in activity during the month, although the malspam vector continued to remain the primary entry vector, with a 41% increase in March 2018. The increase was primarily due to an increase in Emotet activity while simultaneously Kovter activity remained elevated. Cerber, WannaCry, and NanoCore also utilized the malspam vector. The malvertising vector increased by 145% after continuously declining since October 2017, due to sustained CoinMiner activity coinciding with a TinyLoader campaign that brought the malware into the Top 10. An increase in Redyms, as well as continued Gh0st activity, led to an increase in the dropped vector by 20%. Continued increases in Zeus activity led to the multiple vector increasing by 45%.


The MS-ISAC Top 10 Malware refers to the top 10 new actionable event notifications of non-generic malware signatures sent out by the MS-ISAC Security Operations Center (SOC).


Dropped – Malware dropped by other malware already on the system or by an exploit kit.

Malvertising – Malware introduced through a malicious advertisement.

Malspam – Unsolicited emails, which either direct users to download malware from malicious web sites or trick the user into opening malware through an attachment.

Multiple – Refers to malware that currently favors at least two vectors


        1. Kovter is a Trojan, which has been observed acting as click fraud malware or a ransomware downloader. It is disseminated via malspam email attachments containing malicious office macros. Kovter is fileless malware that evades detection by hiding in registry keys. Some reports indicate that Kovter infections have received updated instructions from command and control infrastructure to serve as a remote access backdoor.
        2. Emotet is a modular Trojan that downloads or drops banking Trojans. Initial infection occurs via malspam emails that contain malicious download links, a PDF with embedded links, or a macro-enabled Word attachment. Emotet incorporates spreader modules in order to propagate throughout a network. Emotet is known to download/drop the Pinkslipbot and Dridex banking Trojans. Currently, there are four known spreader modules: Outlook scraper, WebBrowserPassView, Mail PassView, and a credential enumerator.
        3. ZeuS/Zbot is a modular banking Trojan which uses keystroke logging to compromise victim credentials when the user visits a banking website. Since the release of the ZeuS/Zbot source code in 2011, many other malware variants have adopted parts of its codebase, which means that events classified as ZeuS/Zbot may actually be other malware using parts of the ZeuS/Zbot code.
        4. Redyms is a click-fraud trojan that is primarily downloaded and dropped via exploit kit. Redyms has virtualization and sandbox detection and is primarily distributed in the United States.
        5. TinyLoader is a backdoor trojan that is known for delivering point-of-sale and banking trojans, and is delivered via malvertising.
        6. CoinMiner is a cryptocurrency miner that was initially disseminated via malvertising. Once a machine is infected, CoinMiner uses Windows Management Instrument (WMI) and EternalBlue to exploit SMB and spread across a network. CoinMiner uses the WMI Standard Event Consumer scripting to execute scripts for persistence.
        7. Gh0st is a Remote Access Trojan (RAT) used to control infected endpoints. Gh0st is dropped by other malware to create a backdoor into a device, allowing an attacker to fully control the infected device
        8. NanoCore is a RAT spread via malspam as a malicious Excel XLS spreadsheet. As a RAT, NanoCore can accept commands to download and execute files, visit websites, and add registry keys for persistence.
        9. WannaCry is a ransomware worm that uses the EternalBlue exploit to spread. Version 1.0 is known to have a “killswitch” domain, which stops the encryption process. Later versions are not known to have a “killswitch” domain. WannaCry is disseminated via malspam.
        10. Cerber is an evasive ransomware that is capable of encrypting files in offline mode and is known for fully renaming files and appending them with a random extension. There are currently 7 versions of Cerber and it has evolved specifically to evade detection by machine learning algorithms. Currently, v1 is the only version of Cerber for which a decryptor tool is available.