Netskope Threat Labs publishes a quarterly summary blog post of the top threats we track on the Netskope platform. This post aims to provide strategic, actionable intelligence on active threats against enterprise users worldwide.

概要

• OneDrive and SharePoint were on the top of the list of top cloud apps used for malware downloads. GitHub takes third place, being used quite often to download post-exploitation tools.
• The top malware families active in the past quarter included the Infostealer AgentTesla and the Trojan ZLoader.

クラウドマルウェア配信

Attackers attempt to fly under the radar by delivering malicious content via popular cloud apps. Abusing cloud apps for malware delivery enables attackers to evade security controls that rely primarily on domain block lists and URL filtering or don’t inspect cloud traffic.

Attackers achieve the most success in reaching enterprise users when they abuse cloud apps that are already popular in the enterprise. Microsoft OneDrive, the most popular enterprise cloud app, has again held the top spot for the most cloud malware downloads, which it has held for more than six months. 

The top three apps have remained largely unchanged compared to the apps used in the last quarter. When comparing the app usage of this quarter with our last report we noticed a slight increase of SharePoint and GitHub usage. For GitHub specifically the Threat Labs team has been observing it being used to download post-exploitation tools such as Mimikatz and Sharphound. These tools are a good indicator to tell that a threat actor might be already in the environment and that some action needs to be performed in the network.

The top 10 list below reflects attacker tactics, user behavior, and company policy.

Top Malware Families

The following list contains the top malware families blocked by Netskope between April 1 and July 1:

• Downloader.Guloader is a small downloader known for delivering remote access Trojans and infostealers, such as AgentTesla, Formbook, and Remcos.
• Infostealer.AgentTesla is a .NET-based remote access Trojan with many capabilities, such as stealing browsers’ passwords, capturing keystrokes, clipboard, etc.
• RAT.AsyncRAT is an open-source remote administration tool released on GitHub in 2019, designed to remotely control computers via encrypted connection.
• Trojan.ZLoader (a.k.a, DELoader) is a modular trojan based on the leaked ZeuS source code. The malware is capable of performing tasks like capturing screenshots, stealing banking information, providing VNC access, and more.
• Trojan.Grandoreiro is a LATAM banking trojan with the goal of stealing sensitive banking information, commonly targeting Brazil, Mexico, Spain, and Peru.

推奨 事項

Attackers have always sought to evade detection and avoid suspicion in delivering malware. Netskope Threat Labs recommends that you review your security posture to ensure that you are adequately protected against both of these trends:

• Inspect all HTTP and HTTPS downloads, including all web and cloud traffic, to prevent malware from infiltrating your network. Netskope customers can configure their Netskope NG-SWG with a Threat Protection policy that applies to dow