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Netskope Threat Labs publishes a monthly summary blog post of the top threats we are tracking on the Netskope platform. The purpose of this post is to provide strategic, actionable intelligence on active threats against enterprise users worldwide.
Summary
- Attackers continue to attempt to fly under the radar by using cloud apps to deliver malware, with 58% of all malware downloads in March originating from 162 cloud apps.
- While malicious PE (EXE/DLL) files, archives (ZIP, 7Z, GZ), and plain text files (PS, LNK) continue to dominate malware downloads, DMG files are on the rise as attackers target Mac OSX users.
- Trojans continue to represent the majority of malware downloads, used to deliver payloads such as the infostealers RecordBreaker and AgentTesla, and the Stop and Royal ransomware.
Cloud Malware Delivery
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 that do not inspect cloud traffic. In March 2023, 58% of all HTTP/HTTPS malware downloads originated from popular cloud apps, decreasing for the first time after four straight months of increases.
The increasing trend in cloud malware downloads has been driven partially by an increase in the number of distinct cloud apps from which malware are being downloaded. In March 2023, Netskope detected malware downloads from 162 distinct cloud apps, increasing for the third consecutive month.
Attackers achieve the most success reaching enterprise users when they abuse cloud apps that are already popular in the enterprise. Microsoft OneDrive, the most popular enterprise cloud app, has held the top spot for the most cloud malware downloads for more than six months. The other top apps for malware downloads include collaboration apps (Sharepoint), free software hosting sites (GitHub), free web hosting services (Weebly, Squarespace), and cloud storage apps (Box, Azure Blob Storage, Amazon S3, Google Drive). Webmail apps cracked the top ten again after a one-month absence, with Outlook.com coming in at number eight. Microsoft OneDrive reached a new six-month high, while Sharepoint came back down off its six-month high from February. The top ten list is a reflection of attacker tactics, user behavior, and company policy.
