Internet Security Report: Fileless Malware on the Rise, Defenses Failing

Seventy-five percent of malware is going undetected by “traditional malware solutions,” according to a new report. And 74% of threats detected in the last quarter were zero-day malware, an all-time high, according to the researchers.

The report, the Internet Security Report for Q1 2021 from WatchGuard Technologies, found that malicious scripts are delivering fileless malware in the form of an XML external entity. The most widespread was XML.JSLoader, which made the top 10 for the first time in the first quarter of 2021. According to researchers: “The sample WatchGuard identified uses an XML external entity (XXE) attack to open a shell to run commands to bypass the local PowerShell execution policy and runs in a non-interactive way, hidden from the actual user or victim. This is another example of the rising prevalence of fileless malware and the need for advanced endpoint detection and response capabilities.”

A ransomware loader called Zmutzy made the top 2 in Q1. It manifests as a disguised email attachment. According to the researchers: “Associated with Nibiru ransomware specifically, victims encounter this threat as a zipped file attachment to an email or a download from a malicious website. Running the zip file downloads an executable, which to the victim appears to be a legitimate PDF. Attackers used a comma instead of a period in the file name and a manually adjusted icon to pass the malicious zip file off as a PDF. This type of attack highlights the importance of phishing education and training, as well as implementing back-up solutions in the event that a variant like this unleashes a ransomware infection.”

The report highlighted a number of other trends in malware and network attacks as well.

  • Half of the top-10 malware families by volume were new to the top-10, including Ursu, Trojan.IFrame, XML.JSLoader, Zmutzy, and Zum.Androm;

  • Encrypted connections saw less zero-day malware (60.3%) than the overall average (74%);

  • Network attacks reached a three-year high during the first quarter, at 4.2 million Intrusion Prevention Service (IPS) hits on Firebox appliances;

  • More than 5 million malicious domains were blocked by DNSWatch in the quarter, a 281% increase over Q4 2020.

  • Exploits against ProxyLogin Exchange Server flaws increased 1,600%.

A complete report and executive summary can be downloaded here. An infographic with highlights from the report can be accessed here.

About the Author

David Nagel is the former editorial director of 1105 Media's Education Group and editor-in-chief of THE Journal, STEAM Universe, and Spaces4Learning. A 30-year publishing veteran, Nagel has led or contributed to dozens of technology, art, marketing, media, and business publications.

He can be reached at [email protected]. You can also connect with him on LinkedIn at https://www.linkedin.com/in/davidrnagel/ .


Featured

  • robot waving

    Copilot Updates Aim to Personalize AI

    Microsoft has introduced a range of updates to its Copilot platform, marking a new phase in its effort to deliver what it calls a "true AI companion" that adapts to individual users' needs, preferences and routines.

  • open laptop on a child-sized desk in a colorful elementary school classroom with holographic AI icons rising from the screen

    4 Ways Schools Are Using Google AI Tools for Teaching, Learning, and Administration

    In a recent blog post, Google shared an array of education customer stories, showcasing ways schools and districts are using AI tools like Gemini and NotebookLM to transform both learning and administrative tasks.

  • Google Classroom tools

    Google Announces Classroom Updates, New Tools for Chromebooks

    Google has introduced a variety of features across its products for education, announced recently at the 2025 BETT ed tech event in London. Among the additions are enhancements to Google Classroom and new tools for Chromebooks, "designed to help address the diverse needs of students around the world," Google said in a blog post.

  • group of elementary school students designing video games on computers in a modern classroom with a teacher, depicted in a geometric and abstract style

    Using Video Game Design to Teach Literacy Skills

    The Max Schoenfeld School, a public school in the Bronx serving one of the poorest communities in the nation, is taking an innovative approach to improving student literacy.