Authentication Bypass in VMware Tools Host-to-Guest Operations
CVE-2023-20867 is an authentication bypass vulnerability in VMware Tools that affects host-to-guest operations. According to the provided content, a fully compromised ESXi host can cause VMware Tools to fail authentication checks for host-to-guest operations, allowing commands and guest operations to be executed inside guest virtual machines without the normally required authentication. Reporting cited in the content states the flaw was exploited by UNC3886 and later observed in Fire Ant activity to execute unauthenticated Guest Operations from ESXi hosts into Windows, Linux, and PhotonOS guest VMs, including via PowerCLI and vmtoolsd-mediated execution paths. The issue impacts the trust boundary between a compromised hypervisor and its guest VMs by permitting unauthorized interaction with guest systems once the ESXi host is under attacker control.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
14 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A vulnerability (unspecified in the content) affecting VMware Tools that is listed as exploited by the threat actor UNC3886/Volt Typhoon.
A VMware ESXi vulnerability referenced as a zero-day used by UNC3886 in targeted intrusions.
An authentication bypass flaw used to execute commands inside guest virtual machines without required authentication in VMware environments.
A vulnerability in VMware Tools leveraged post-compromise to enable direct interaction with guest VMs (via PowerCLI), supporting lateral movement and credential access from VM memory snapshots.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.