CIS Logo
tagline: Confidence in the Connected World
HomeResourcesBlog postTop 10 Malware January 2018

Top 10 Malware January 2018

The MS-ISAC observed a 20% decrease in new malware infections from December 2017 to January 2018. Kovter continued to dominate the SLTT government landscape, accounting for 55% of Top 10 Malware notifications. 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. The malspam vector continues to remain the primary entry vector, increasing by 8% in January 2018, mostly due to the high levels of Kovter. The MS-ISAC did not observe any sustained Emotet campaigns, leading to a decrease in events in January 2018. The MS-ISAC observed and verified a WannaCry 1.0 outbreak, which was the first verified activity since the first WannaCry attack in May 2017.  The malvertising vector continues a steady decline that began in October 2017. It decreased by 56% in January 2018, mostly due to the decline in CoinMiner. The addition of Mirai and Redyms to the Top 10 Malware increased the dropped vector by 48% and due to a slight increase in Zeus, the multiple vector increased by 18.




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.

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

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

  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.
    1. Outlook Scraper: a tool that scrapes names and email addresses from the victim’s Outlook accounts and uses that information to send out phishing emails from the compromised account;
    2. WebBrowserPassView: a password recovery tool that captures passwords stored by Internet Explorer, Mozilla Firefox, Google Chrome, Safari, and Opera and passes them to the credential enumerator module;
    3. Mail PassView: a password recovery tool that reveals passwords and account details for various email clients such as Microsoft Outlook, Windows Mail, Mozilla Thunderbird, Hotmail, Yahoo! Mail, and Gmail and passes them to the credential enumerator module;
    4. Credential Enumerator: a self-extracting RAR file containing a bypass and a service component. The bypass component is used for enumeration of network resources and either finds writable share drives or tries to brute force user accounts, including the administrator account. Once an available system is found, Emotet then writes the service component on the system, which writes Emotet onto the disk.
  3. 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.
  4. 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.
  5. 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.
  6. Gh0st is a 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
  7. NanoCore is a Remote Access Trojan (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.
  8. Ursnif, and its variant Dreambot, are banking trojans known for weaponizing documents. Ursnif recently upgraded its web injection attacks to include TLS callbacks in order to obfuscate against anti-malware software. Ursnif collects victim information from login pages and web forms
  9. Mirai is a malware botnet known to compromise Internet of Things (IoT) devices in order to conduct large-scale distributed denial of service (DDoS) attacks. Mirai is dropped after an exploit has allowed the attacker to gain access to a machine.
  10. Redyms is a click-fraud trojan that is primarily downloaded via exploit kit. Redyms has virtualization and sandbox detection and is primarily distributed in the United States.


The MS-ISAC is the focal point for cyber threat prevention, protection, response, and recovery for the nation’s state, local, tribal, and territorial (SLTT) governments. More information, as well as 24x7 cybersecurity assistance for SLTT governments, is available by contacting the MS-ISAC at 866-787-4722,, or