VMware ESXi Sandbox Escape Flaw CVE-2025-22225 Now Weaponized in Ransomware Attacks

A critical security flaw in VMware’s ESXi virtualization platform is now actively being exploited by ransomware groups, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) confirmed Wednesday. The vulnerability, tracked as CVE-2025-22225, allows attackers to escape the ESXi sandbox and execute arbitrary code with elevated privileges—a dangerous capability that can lead to complete system compromise.

The Flaw and Its Origins

In March 2025, Broadcom (which acquired VMware) patched CVE-2025-22225 alongside two other vulnerabilities—CVE-2025-22226 (a memory leak) and CVE-2025-22224 (a time-of-check-time-of-use flaw). All three were designated as zero-day exploits actively being used in attacks at the time of patching.

“An attacker with privileges within the VMX process may trigger an arbitrary kernel write leading to an escape of the sandbox,” Broadcom explained in its advisory. This sandbox escape vulnerability affects multiple VMware products including ESXi, Fusion, Cloud Foundation, vSphere, Workstation, and Telco Cloud Platform.

The flaw’s severity stems from its potential chainability. When combined with the other two vulnerabilities, attackers with privileged administrator or root access can execute sophisticated attacks that completely bypass VMware’s security boundaries.

Earlier Exploitation Discovered

Cybersecurity firm Huntress published findings last month suggesting that Chinese-speaking threat actors had been exploiting these vulnerabilities in sophisticated zero-day attacks since at least February 2024—nearly a year before their official disclosure. This timeline indicates that sophisticated adversaries maintained access to these flaws for extended periods, potentially compromising countless enterprise systems.

CISA’s Warning and Federal Response

CISA first added CVE-2025-22225 to its Known Exploited Vulnerabilities (KEV) catalog in March 2025, mandating federal agencies to patch their systems by March 25, 2025, under Binding Operational Directive (BOD) 22-01. The agency’s latest update confirms the vulnerability’s use in active ransomware campaigns.

“Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable,” CISA advises organizations still running vulnerable systems.

Why VMware Vulnerabilities Attract Attackers

VMware products are ubiquitous in enterprise environments, making them prime targets for both ransomware gangs and state-sponsored hacking groups. These platforms often host critical infrastructure and store sensitive corporate data, creating high-value targets for cybercriminals seeking maximum impact and ransom potential.

This pattern of targeting VMware vulnerabilities isn’t new. In October 2024, CISA ordered government agencies to patch CVE-2025-41244 in Broadcom’s VMware Aria Operations and VMware Tools software after discovering Chinese hackers had been exploiting it since October 2024. More recently, in January 2025, CISA flagged another critical VMware vCenter Server vulnerability (CVE-2024-37079) as actively exploited, requiring federal agencies to secure their servers by February 13.

Hidden Ransomware Exploitation Trends

In related developments, cybersecurity company GreyNoise reported this week that CISA has “silently” tagged 59 security flaws as being used in ransomware campaigns throughout 2024 alone. This revelation suggests that ransomware groups are exploiting a much broader range of vulnerabilities than publicly acknowledged, with many campaigns flying under the radar.

The discovery of CVE-2025-22225’s use in ransomware attacks serves as a stark reminder of the persistent threat posed by unpatched vulnerabilities in enterprise environments. Organizations running VMware infrastructure should immediately review their patching status and implement recommended mitigations to prevent potential compromise.

Tags:

VMware ESXi, CVE-2025-22225, ransomware attacks, sandbox escape, Broadcom, CISA, zero-day vulnerability, cybersecurity threat, enterprise security, virtualization platform, critical vulnerability, patch immediately, data breach risk, Chinese hackers, ransomware gangs, virtual machine security, kernel write vulnerability, VMware products, security patching, cyber attack campaign

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