cbcvebase.
CVE-2023-34048
published 2023-10-25

CVE-2023-34048: vCenter Server contains an out-of-bounds write vulnerability in the implementation of the DCERPC protocol. A malicious actor with network access to vCenter…

PriorityP197critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
KEVITWEXPLOIT
CISA Known Exploited Vulnerabilitydue 2024-02-12
Exploited in the wild
EPSS
99.43%
99.9th percentile
vCenter Server contains an out-of-bounds write vulnerability in the implementation of the DCERPC protocol. A malicious actor with network access to vCenter Server may trigger an out-of-bounds write potentially leading to remote code execution.

Affected

7 ranges
VendorProductVersion rangeFixed in
vmwarevcenter_server
vmwarevcenter_server
vmwarevcenter_server4.0 – 5.5
vmwarevmware_cloud_foundation
vmwarevmware_cloud_foundation
vmwarevmware_vcenter_server>= 7.0 < 7.0U3o7.0U3o
vmwarevmware_vcenter_server>= 8.0 < 8.0U28.0U2

Detection & IOCsextracted from sources · hover to see the quote

filenamepython20.dll
filenameweb.rar
filenameweb1.rar
filenameweb2.rar
other10014-win-nic-32-v
other10013-linux-64-V
commandcertutil -encode
pathc:\inetpub\wwwroot
  • Monitor for python.exe or pythonw.exe loading a DLL named python20.dll — a strong indicator of DLL side-loading used by post-exploitation actors following CVE-2023-34048 compromise of vCenter.
  • Detect FRP (Fast Reverse Proxy) samples containing the unique authentication token 'frpforzhangwei' or proxy names matching the pattern '10014-win-nic-32-v', '20012-linux-64-V', or '10013-linux-64-V'.
  • Alert on certutil -encode being invoked against .rar archives in web server directories, a technique used to exfiltrate data via web shell output without file upload.
  • Hunt for VirtualPita and VirtualPie backdoors deployed on ESXi hosts via maliciously crafted vSphere Installation Bundles (VIBs) — post-exploitation artifacts following CVE-2023-34048 exploitation by UNC3886.
  • Restrict and monitor network access to vCenter Server management interfaces; CVE-2023-34048 is exploitable by any actor with network access via a specially crafted DCERPC packet, requiring no authentication.
  • Detect creation of archive files (web.rar, web1.rar, web2.rar) under c:\inetpub\wwwroot as an indicator of staged exfiltration following initial access.
  • Monitor for GodZilla and AntSword web shell deployment on Linux and Windows servers as initial post-exploitation indicators associated with actors leveraging CVE-2023-34048.
  • ·CVE-2023-34048 was exploited as a zero-day by UNC3886 since at least late 2021, well before public disclosure — environments should assume potential historic compromise even if patched promptly after disclosure.
  • ·No official workaround exists for CVE-2023-34048; the only mitigation is patching. Strict network perimeter controls on vSphere management interfaces are recommended as a compensating control.
  • ·Not every post-exploitation tool in the CL-UNK-1068 toolset was used in every intrusion; detection coverage should span the full toolkit rather than relying on any single indicator.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vulncheck9.8CRITICAL
cisa9.8CRITICAL
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