Article
Threat Actors Exploiting New ESXi Vulnerability
Threat Actors
Cyber Threats
Combating Ransomware

In late July, researchers at Microsoft reported on an authentication bypass vulnerability in VMware ESXi that is being exploited by several ransomware groups, including Black Basta and Akira. The vulnerability, identified as CVE-2024-37085, allows a threat actor to create a group named “ESX Admins” on the Active Directory domain and add users to it. By default, any member of the group has full administrative access. With the vulnerability being actively exploited, it is recommended that organizations with domain-joined ESXi hypervisors install the update VMware released on their website to fix the issue.
What’s New and Notable
CVE-2024-37085 can be exploited in several ways, either by adding an “ESX Admins” group to the domain and adding users to it or simply by renaming any group in the domain to “ESX Admins.”
Microsoft researchers observed threat actors earlier this year gaining initial access to a victim and then creating an “ESX Admins” group to encrypt the hosted virtual machines on the ESXi hypervisor with Black Basta ransomware.
In addition to installing VMware’s security update to fix the CVE-2024-37085 vulnerability, researchers also recommend users protect their privileged accounts from unauthorized users, identify any critical assets and potential vulnerabilities in their network, and maintain adequate monitoring, backups, and recovery plans.
Analyst Comments
VMware’s ESXi is a popular product used by thousands of organizations worldwide for virtualizing servers, which often host critical applications, data, and backups. As such, threat actors have increasingly targeted ESXi in recent years, with several threat groups deploying dedicated Linux encryptors for ESXi virtual machines. The latest vulnerability allows threat actors to gain privilege escalation, move laterally throughout the network, steal data, or deploy malicious payloads. Given this threat, organizations with domain-joined ESXi hypervisors should apply the available update provided by VMware. In addition to the software update and risk mitigation recommendations provided by researchers, organizations should also monitor their networks for signs of compromise and consider additional security measures to protect against vulnerabilities in the future.
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Article
Threat Actors Leverage AI for EDR Evasion
A threat actor has developed and deployed a ransomware attack toolkit enhanced with AI-assisted development workflows, enabling automated Active Directory (AD) discovery and improved EDR evasion capabilities. The toolkit leverages agent-based AI systems, such as Claude’s Opus and Cursor agents, for iterative malware development, testing, and refinement.
What’s Notable and Unique
Researchers have highlighted that this toolkit can not only generate ransomware code but also bypass sophisticated security defenses and identify AD networks for malware distribution.
The framework incorporates multiple capabilities, including automated AD discovery and reconnaissance mechanisms, iterative EDR testing environments to refine evasion techniques, and a command-and-control (C2) infrastructure that leverages Telegram APIs and Cloudflare redirectors for stealth.
Additionally, some agents were tasked with checking security research and technical posts for various bypass techniques. The agents recognized what was required for reproduction, extracted the techniques, mapped them to the MITRE ATT&CK knowledge base of adversary behaviors, set up a test lab, carried out the methodology, and reported the results.
After a few repetitions, the modules seemed to avoid nearly all EDR solutions, despite the agent’s initial suggestion of a high failure rate. Although researchers found no evidence that AI was embedded in deployed malware or was operating independently in victim environments, the technology was still used to accelerate the iterative process of developing, testing, and refining payloads against security products, shortening the period between the publication of offensive security research and its practical implementation by threat actors.
Analyst Comments
AI-driven tools like this could accelerate the pace and sophistication of ransomware attacks, enabling even relatively inexperienced actors to launch high-impact campaigns. This development underscores the urgent need for security solutions to adapt to AI-assisted threats. Organizations must respond by strengthening detection engineering, improving visibility across environments, and maintaining robust security fundamentals.
Sources
AI-built ransomware toolkit automates EDR evasion, AD discovery
Pointing a Cursor at evading detection
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Arete's 2026 Q1 Crimeware Report
Harness Arete’s unique data and expertise on extortion and ransomware to inform your response to the evolving threat landscape.
Article
CMS Vulnerability Leads to ClickFix Campaign
Threat actors compromised at least 700 education and technology websites in a recent ClickFix campaign by exploiting a critical SQL injection flaw (CVE-2026-26980) in the Ghost content management system (CMS). Adversaries combined the vulnerability with the ClickFix social engineering tactic to steal admin keys and inject a malicious JavaScript that delivers a fake Cloudflare or CAPTCHA verification pop-up, tricking victims into copying and pasting a malicious command into their systems.
What’s Notable and Unique
Rather than targeting the end user first, this campaign is unique in its initial exploitation of the system, followed by social engineering attempts. This hybrid attack style is likely being leveraged to bypass traditional defenses.
This recent campaign also highlights how trusted web properties can be weaponized at scale and coupled with unpatched CMS vulnerabilities. Rather than using the CMS compromise to perpetrate a single attack, threat actors turned it into a supply-chain attack that ultimately affected over 700 trusted websites.
Analyst Comments
As network defenders and their tools enhance threat detection capabilities, adversaries increasingly seek methods to bypass these defenses. By combining vulnerability exploitation, social engineering techniques, and staging for ancillary attacks, this campaign successfully bypassed traditional defenses and inflicted significant impact. Defending against hybrid cyberattacks requires comprehensive security controls beyond simply patching vulnerabilities. Organizations should focus on limiting movement within the environment, detecting abuse of trusted applications, and preventing end-user manipulation.
Sources
700+ education and tech websites hijacked in huge ClickFix malware campaign
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Ghost CMS Vulnerability Exploited to Infect 700 Sites With ClickFix Malware
Article
Threat Actors Leverage Fake JPEG Files for Initial Access
In a recent campaign, researchers observed threat actors using fake JPEG image files as a delivery mechanism to initiate the deployment of additional malicious components. The false JPEG files are typically distributed via phishing emails or other social engineering-based lures, and are actually PowerShell-based malware that deploys a trojanized version of ConnectWise ScreenConnect to establish and maintain persistence in the compromised environment.
What’s Notable and Unique
This campaign leverages JPEG images as the initial lure, where the images are not merely decoys but part of the infection workflow. Victims are typically led to download or open an image that triggers hidden execution logic or redirects them to a payload-delivery sequence that initiates later stages of the intrusion chain.
The attack chain is designed to blend into legitimate environments, making detection more difficult. Execution typically relies on scripted or native Windows components, often including PowerShell or other living-off-the-land binaries, enabling fileless or near-fileless execution and reducing forensic artifacts on disk.
The multistage design ensures that the initial JPEG does not directly contain the full payload but instead triggers retrieval or decryption steps that progressively assemble the final malicious components in memory.
Analyst Comments
This campaign illustrates how threat actors continue to blur the line between legitimate file handling and malicious execution chains, indicating potential overlap with remote management or administrative tooling. The use of JPEG-based staging combined with script-based execution reflects a broader evolution toward a stealth-first intrusion design, in which file formats serve as triggers rather than payload containers.
Sources
OPERATION SILENTCANVAS : JPEG BASED MULTISTAGE POWERSHELL INTRUSION



