Ransomware gangs exploit VMware ESXi bug CVE-2024
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2023-28252 | Heap Overflow in Microsoft Windows CLFS Driver Enables Local Privilege Escalation CVE-2023-28252 is a heap-based buffer overflow (CWE-122) in the Microsoft Windows Common Log File System (CLFS) driver that allows privilege escalation. The flaw is triggered when the kernel's CLFS driver processes malformed or maliciously crafted log file data, corrupting heap memory; an attacker who can already run code on a target system (e.g., a low-privileged user or an attacker chained with another flaw such as a remote code execution bug) can leverage it to gain SYSTEM-level privileges. Because the CLFS driver ships with supported Windows client and server releases, essentially the entire Windows installed base is potentially exposed. The vulnerability is being actively exploited: CISA added it to the KEV catalog on 2023-04-11 with known ransomware use, and EPSS estimates a 49.0% probability of exploitation within 30 days (99th percentile). It was addressed in Microsoft's April 2023 security updates, and the required remediation action is to apply the vendor updates. Do: Apply Microsoft's April 2023 (or later) cumulative security updates to all Windows clients and servers per vendor instructions, prioritizing high-value and domain infrastructure systems given the known ransomware use; there is no public PoC or known workaround, so patching is the primary mitigation. Note that this is a local elevation-of-privilege flaw, so also hunt for prior low-privilege access or exploitation chains on hosts, and confirm remediation by checking installed update levels across the estate. | 7.8 | 49% | KEV ransomware PoC |
| masshundreds of millions of Windows devices (the CLFS driver is present across essentially all modern Windows 10/11 and Windows Server installations) | |
| CVE-2024-37085 | Authentication Bypass in VMware ESXi via AD Group Recreation VMware ESXi is vulnerable to an authentication bypass (CWE-305) when the host is configured to use Active Directory for user management. An attacker who has sufficient Active Directory permissions can delete the AD group tied to ESXi administration (typically the default 'ESXi Admins' group) and then re-create it, causing ESXi to treat the re-created group as the original administrator group. This grants the actor full access to the ESXi host without needing ESXi credentials themselves. Only ESXi hosts that were joined to and configured with Active Directory for user management are affected; hosts using local authentication are not. Exploitation is confirmed in the wild: the flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2024-07-30 with known ransomware use, and EPSS assigns a high 26.8% probability of exploitation in the next 30 days (98th percentile). Do: Apply the security updates or mitigations published in the vendor's (VMware/Broadcom) advisory for your ESXi release, per the CISA KEV required action. As interim mitigation, protect the configured AD admin group (default 'ESXi Admins') from deletion or re-create it with the original identity, and restrict AD permissions that allow arbitrary group deletion. Since ransomware use is known, audit AD logs for deletion/re-creation of the 'ESXi Admins' group and verify integrity of any AD-joined ESXi hosts. | 7.2 | 27% | KEV ransomware |
| mass≈100,000+ ESXi hosts (tens of thousands are internet-exposed in public scans, and the installed base is far larger, though only AD-joined hosts are vulnerable) |
Full article389 words · extracted from securityaffairs.com · click to collapse
Microsoft warns that ransomware gangs are exploiting the recently patched CVE-2024-37085 flaw in VMware ESXi flaw.
Microsoft researchers warned that multiple ransomware gangs are exploiting the recently patched vulnerability CVE-2024-37085 (CVSS score of 6.8) in VMware ESXi flaw.
“Microsoft researchers have uncovered a vulnerability in ESXi hypervisors being exploited by several ransomware operators to obtain full administrative permissions on domain-joined ESXi hypervisors.” warned Microsoft.
The flaw is an authentication bypass vulnerability in VMware ESXi.
“A malicious actor with sufficient Active Directory (AD) permissions can gain full access to an ESXi host that was previously configured to use AD for user management by re-creating the configured AD group (‘ESXi Admins’ by default) after it was deleted from AD.” reads the advisory published by the virtualization giant.
The company released patches for security vulnerabilities affecting ESXi 8.0 and VMware Cloud Foundation 5.x. However, no patches are planned for the older versions, ESXi 7.0 and VMware Cloud Foundation 4.x. Users of the unsupported versions are recommended to upgrade to newer versions to receive security updates and support.
Microsoft reported that multiple financially motivated groups like Storm-0506, Storm-1175, and Octo Tempest have already exploited this vulnerability to deploy ransomware.
“Microsoft security researchers identified a new post-compromise technique utilized by ransomware operators like Storm-0506, Storm-1175, Octo Tempest, and Manatee Tempest in numerous attacks.” continues Microsoft. “In several cases, the use of this technique has led to Akira and Black Basta ransomware deployments. “
Earlier this year, the Storm-0506 group breached an engineering firm in North America and deployed the Black Basta ransomware by exploiting the flaw CVE-2024-37085 to gain elevated privileges to the ESXi hypervisors.
“The threat actor gained initial access to the organization via Qakbot infection, followed by the exploitation of a Windows CLFS vulnerability (CVE-2023-28252) to elevate their privileges on affected devices. The threat actor then used Cobalt Strike and Pypykatz (a Python version of Mimikatz) to steal the credentials of two domain administrators and to move laterally to four domain controllers.” continues Microsoft.
The attackers created the ‘ESX Admins’ group in the domain and added a new user account to it. The threat actors encrypted the ESXi file system and caused the lost of functionality of the hosted virtual machines on the ESXi hypervisor.
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(SecurityAffairs – hacking, CVE-2024-37085)
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