Top 10 Malware May 2019
The malware variants comprising the Top 10 Malware list for May 2019 is consistent with the previous month’s list with two exceptions. WannaCry dropped out of the Top 10 Malware for the month and Pushdo made the list in the number 10 spot. Pushdo is a spam botnet infecting computers since 2007. The proportion of Top 10 Malware to Total Malware activity remained around 60% after peaking at 64% in April.
In May 2019, malware utilizing multiple initiation vectors accounts for the greatest number of alerts in the Top 10 malware list. Both the malspam and network initiation vectors decreased in activity, while malware dropped via other malware increased. An increase in Trickbot infections accounts for the activity within the multiple category. After February, the malvertisement vector returned to its previous levels of non-activity, as no malware using this vector made it into the Top 10 list. Previously, Wannacry was the only malware in the Top 10 utilizing the network vector. Disabling these signatures brought activity in that vector to zero.
Dropped – Malware delivered by other malware already on the system, an exploit kit, infected third-party software, or manually by a cyber threat actor. Currently Gh0st, Qakbot, and Pushdo are being dropped.
Multiple – Malware that currently favors at least two vectors. ZeuS, CoinMiner and Trickbot are currently utilizing multiple vectors. ZeuS is dropped by other malware, but it is also delivered via malvertisement. CoinMiner utilizes the malspam and dropped vectors. Trickbot is dropped by Emotet and also delivered via malspam
Malspam – Unsolicited emails, which either direct users to malicious web sites or trick users into downloading or opening malware. Top 10 Malware using this technique include NanoCore, Kovter, Dridex and Emotet.
Network – Malware introduced through the abuse of legitimate network protocols or tools, such as SMB protocol or remote PowerShell. Following the disabling of the Wannacry signatures, this vector now has no activity for this month.
Malvertisement – Malware introduced through malicious advertisements. Shlayer, a MacOS trojan, is the first malware since April 2018 to rely on this vector within the Top 10 Malware list.
- 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.
- Trickbot is a modular banking trojan that is known to be dropped by Emotet as well as spread via malspam campaigns. Trickbot is also known to download the IcedID banking Trojan.
- 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.
- 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.
- Dridex is a banking trojan that uses malicious macros in Microsoft Office with either malicious embedded links or attachments. Dridex is disseminated via malspam campaigns.
- 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. CoinMiner spreads through malspam or is dropped by other malware.
- 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.
- 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.
- 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.
- Pushdo is a botnet that has been active since 2007 and operates as a service for malware and spam distribution. Pushdo is known to distribute the Cutwail spambot. The malware uses encrypted communication channels and domain generation algorithms to send instructions to its zombie hosts.