Traditional anti-malware solutions miss nearly 75% of threats, according to new research from WatchGuard Technologies.

WatchGuard's Internet Security Report for Q1 2021 finds that 74% of threats detected last quarter were zero-day malware - or those for which a signature-based antivirus solution did not detect at the time of the malware release - capable of getting around conventional antivirus solutions.

The report also covers common malware variants, hacker tricks, the top targets within an organisation, and more.

For one, WatchGuard's report finds that the fileless malware variant XML.JSLoader has exploded in popularity.

XML.JSLoader is a malicious payload that appeared for the first time in both WatchGuard's top malware by volume and most widespread malware detections lists.

It was also the variant WatchGuard detected most often via HTTPS inspection in Q1.

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, WatchGuard states.

The report also finds that a simple file name trick is proving to help hackers pass off ransomware loader as legitimate.

PDF attachments Ransomware loader Zmutzy surfaced as a top-two encrypted malware variant by volume in Q1.

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 backup solutions in the event that a variant like this unleashes a ransomware infection, the researchers state.

In addition, WatchGuard finds that threat actors are continuing to attack IoT devices.

According to WatchGuard, while it didn't make WatchGuard's top 10 malware list for Q1, the Linux.Ngioweb.B variant has been used by adversaries recently to target IoT devices.

The first version of this sample targeted Linux servers running WordPress, arriving initially as an extended format language (EFL) file.

Another version of this malware turns the IoT devices into a botnet with rotating command and control servers.

Highlighting another top target, the report states that network attacks have surged more than 20%.

WatchGuard appliances detected more than 4 million network attacks, a 21% increase compared to the previous quarter and the highest volume since early 2018.

Corporate servers and assets on site are still high-value targets for attackers despite the shift to remote and hybrid work, so organisations must maintain perimeter security alongside user-focused protections.

Recently, an old directory traversal attack technique has made a comeback, according to the report.

WatchGuard detected a new threat signature in Q1 that involves a directory traversal attack via cabinet (CAB) files, a Microsoft-designed archival format intended for lossless data compression and embedded digital certificates.

A new addition to WatchGuard's top 10 network attacks list, this exploit either tricks users into opening a malicious CAB file using conventional techniques, or by spoofing a network-connected printer to fool users into installing a printer driver via a compromised CAB file.

WatchGuard also finds that HAFNIUM zero days have provided lessons on threat tactics and response best practices.

Last quarter, Microsoft reported that adversaries used the four HAFNIUM vulnerabilities in various Exchange Server versions to gain full, unauthenticated system remote code execution and arbitrary file-write access to any unpatched server exposed to the Internet, as most email servers are.

WatchGuard incident analysis dives into the vulnerabilities and highlights the importance of HTTPS inspection, timely patching and replacing legacy systems.

Finally, the report finds that attackers are co-opting legitimate domains in cryptomining campaigns.

In Q1, WatchGuard's DNSWatch service blocked several compromised and outright malicious domains associated with cryptomining threats.

Cryptominer malware has become increasingly popular due to recent price spikes in the cryptocurrency market and the ease with which threat actors can siphon resources from unsuspecting victims.

WatchGuard chief technology officer Corey Nachreiner says, “Last quarter saw the highest level of zero-day malware detections we've ever recorded.

"Evasive malware rates have actually eclipsed those of traditional threats, which is yet another sign that organisations need to evolve their defences to stay ahead of increasingly sophisticated threat actors.

"Traditional anti-malware solutions alone are simply insufficient for today's threat environment. Every organisation needs a layered, proactive security strategy that involves machine learning and behavioural analysis to detect and block new and advanced threats.

WatchGuard's quarterly research reports are based on anonymised Firebox Feed data from active WatchGuard Fireboxes whose owners have opted in to share data to support the Threat Labs research efforts.

In Q1, WatchGuard blocked a total of more than 17.2 million malware variants (461 per device) and nearly 4.2 million network threats (113 per device).