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The vulnerability resides within the vCenter Server’s DCERPC protocol implementation. DCERPC is used for remote procedure calls, and the server fails to properly validate the size of incoming requests before copying data into a heap-based buffer. A specially crafted network packet containing a maliciously large DCERPC fragment can overflow the allocated buffer. This corruption overwrites adjacent heap memory structures, including critical function pointers and metadata. By precisely controlling the overflow data, an attacker can hijack the execution flow of the process. This is achieved by overwriting a function pointer or a return address on the heap. When the corrupted pointer is later dereferenced and called, the process executes attacker-supplied shellcode placed within the crafted packet. The exploit bypasses standard heap mitigations by shaping the heap layout through repeated allocations. The attack requires no authentication and is network-accessible via the vCenter Server’s management interfaces. Successful exploitation grants the attacker full control over the target system with the privileges of the vCenter Server service, typically running as root or SYSTEM.
Platform: vCenter Server
Version: 6.5 6.7 7.0
Vulnerability: Heap Overflow RCE
Severity: Critical
date: 2021-05-25
Prediction: Patched May 2021
What Undercode Say:
Analytics:
nmap -sV --script vmware-version
Packet skeleton for DCERPC fragment
import socket
struct.pack('>I', 0xdeadbeef) Malformed header
socket.sendto(payload, (target, 135))
Exploit:
Craft oversized DCERPC fragment. Target heap grooming. Overwrite function pointer. Execute shellcode from packet. Gain root shell.
Protection from this CVE
Apply vendor patch. Isolate management network. Use firewall rules.
Impact:
Remote Code Execution. Full System Compromise. Critical Infrastructure Risk.
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Sources:
Reported By: www.cve.org
Extra Source Hub:
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