UNC3886: vCenter RCE to ESXi Persistence (CVE-2023-34048)
Orbivex Aerospace runs its virtualisation estate on a vCenter Server appliance and three ESXi hypervisors, with the vCenter HTTPS management interface published to the internet. The platform team opened a ticket during the morning shift: the appliance had logged a management daemon terminating on a fatal signal and restarting, and the hypervisor integrity summary listed package and startup-file entries the change record does not account for. Work the vCenter, ESXi and firewall telemetry and establish what reached the estate, how it moved between the management plane and the hypervisors, and how far it got.
Start this operation
Investigation Tasks
Complete each task by investigating alerts and submitting your findings.
Locate the exploit entry point
20The vCenter appliance logged something unusual before anything else happened: a process crash. Determine what service was targeted and what external address drove the crash.
Name the crashed service
15After the exploit landed, a specific VMware appliance process crashed with a segfault. Identify that process by name - it is the first DFIR indicator that exploitation succeeded rather than just failing noisily.
Trace the staging activity
20Immediately after gaining execution on the vCenter appliance, the attacker transferred files onto it. Identify the hidden directory created to hold the staged tooling.
Identify the SSH enablement mechanism
15Before logging into the ESXi hypervisors directly, the attacker had to turn on SSH. Determine the vCenter account used to issue that task.
Name the malicious VIB package
20The backdoor was delivered as a VMware Installation Bundle. Identify the package name that was installed without a valid VMware signature.
Find the persistent backdoor binary
20The VIB dropped a persistent binary that is not part of any standard ESXi installation. Identify its full path on the ESXi filesystem.
Locate the covert C2 channel destination
20The VMCI reverse-tunnel daemon opened a persistent outbound connection from each ESXi host to an external address. Identify that destination.
Trace the guest credential harvest
20The backdoor reached inside running guest VMs to steal credentials without touching the guest network stack. Identify the guest account whose credentials were targeted.
Map the VIB backdoor to its ATT&CK technique
25Unsigned VIBs that persist a backdoor across ESXi reboots represent a documented but underdetected hypervisor technique. Identify the ATT&CK technique that describes modifying the hypervisor's installed package image.
9 tasks · 175 points total
Training Tools
Skills You'll Build
Complex multi-stage investigations. Realistic noise, ambiguous indicators, lateral movement.
Prerequisites
- Basic understanding of security alerts
- Experience with log analysis tools
- Familiarity with SIEM concepts
- Familiarity with XDR concepts
- Familiarity with Firewall concepts
Ready to investigate?
More Operations
View allThe Template That Read the Disk
The file-transfer portal that Tideglow Logistics' partners upload to spent a morning returning host files it was never meant to publish, and finished it running an administrator session nobody had logged into. The root cause is CVE-2024-4040 in CrushFTP 10.6.0. Walk the access logs and firewall traffic step by step to trace how a client holding no credentials turned a request parameter into a read of the host, and that read into a takeover.
OneNote Attachment to RAT: A Guided First Investigation
A logistics contracts employee at Glacierline Freight opens an attachment that arrived in her inbox and clicks a button inside it. Minutes later her workstation is running something that appears on no software inventory and is talking to a host that no business process uses. Walk the email gateway records, the file artifacts and the endpoint process tree one step at a time, and work out for yourself which message carried the delivery, what landed on disk, and what ran.
Hijacked Discord Invite to ClickFix Loader: Tracing the Lure
A finance analyst at Halcyon Wealth Partners followed a recycled Discord invite that quietly redirected the browser to a fake verification page. They did what the page asked, and inside the hour the workstation was running a remote-access trojan alongside an info-stealer that shipped browser data straight out of the building. Walk the proxy, endpoint and firewall evidence step by step to trace the lure, the loader, the C2 beacon and the data theft.