CIS Logo
tagline: Confidence in the Connected World

Top 10 Malware February 2019

Overall, the MS-ISAC® observed a 13% increase in total malware activity from January 2019 to February 2019. Of the Top 10 Malware activity, which made up 67% of total malware notifications sent, it is 10% less than in January 2019. The Top 10 Malware continues to make up greater than 60% of total malware activity. This trend is highly likely to continue based on the make-up of the malware environment and as cyber threat actors continue to actively update the malware in the Top 10. Shlayer, a MacOS Trojan, is new to the Top10 Malware this month and is the first malware since March 2018 to use malvertising as its primary infection vector.


In February 2019, malvertising was the most prominent category. It acted as the primary infection vector for malware in the Top 10 list for the first time in 11 months. Both the dropped and network infection vectors increased in activity over the previous month, while malware distributed via multiple vectors and malspam decreased significantly. Total activity associated with the network vector increased over January due to WannaCry activity. WannaCry utilizes the network vector by abusing vulnerabilities in the Server Message Block (SMB) protocol. The multiple vector decreased due to a fall in ZeuS activity.


Dropped – Malware delivered by other malware already on the system, an exploit kit, infected third-party software, or manually by a cyber threat actor.

Multiple – Malware that currently favors at least two vectors.

Malspam – Unsolicited emails, which either direct users to malicious web sites or trick users into downloading or opening malware.

Network – Malware introduced through the abuse of legitimate network protocols or tools, such as SMB protocol or remote PowerShell.

Malvertising – Malware introduced through malicious advertisements.

  1. Shlayer is a downloader and dropper for MacOS malware. It is primarily distributed through malicious websites, hijacked domains, and malvertizing posing as a fake Adobe Flash updater.
  2. WannaCry is a ransomware cryptoworm that uses the EternalBlue exploit to spread via SMB protocol. Version 1.0 has a “killswitch” domain, which stops the encryption process.
  3. IcedID is a modular banking Trojan that targets banks, payment card providers, and payroll websites. IcedID utilizes the same distribution infrastructure as Emotet. The malware can monitor a victim’s online activity by setting up local proxies for traffic tunneling, employing web injection and redirection attacks. It propagates across a network by infecting terminal servers.
  4. Gh0st is a RAT used to control infected endpoints. Gh0st is dropped by other malware to create a backdoor into a device that allows an attacker to fully control the infected device.
  5. 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.
  6. ZeuS 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 source code in 2011, many other malware variants have adopted parts of it’s codebase, which means that events classified as ZeuS may actually be other malware using parts of the ZeuS code.
  7. Kovter is a fileless click fraud malware and a downloader that evades detection by hiding in registry keys. Reporting indicates that Kovter can have backdoor capabilities and uses hooks within certain APIs for persistence.
  8. Emotet is a modular infostealer that downloads or drops banking trojans. It can be delivered through either malicious download links or attachments, such as PDF or macro-enabled Word documents. Emotet also incorporates spreader modules in order to propagate throughout a network. In December 2018, Emotet was observed using a new module that exfiltrates email content.
  9. CoinMiner is a cryptocurrency miner that uses Windows Management Instrumentation (WMI) and EternalBlue to spread across a network. CoinMiner uses the WMI Standard Event Consumer scripting to execute scripts for persistence.
  10. Qakbot is financial malware designed to target governments and businesses for financial fraud and known for its wormability on a network. Qakbot installs a keylogger to steal user credentials. It monitors network traffic, specifically traffic to online banking websites and can piggyback on a user’s active banking session by intercepting authentication tokens. It is currently being dropped by Emotet.