CVE-2025-20738: MediaTek WLAN AP驱动越界写入权限提升漏洞

// CVE-2025-20738 PoC - MediaTek WLAN AP Driver Out of Bounds Write // Note: This is a conceptual PoC for educational purposes only // Requires existing system-level access to exploit #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdint.h> // Simulated vulnerable driver structure typedef struct { uint32_t buffer_size; uint8_t* data_buffer; uint32_t flags; } wlan_ap_driver_ctx_t; // Vulnerable function with incorrect bounds check int vulnerable_write(wlan_ap_driver_ctx_t* ctx, uint8_t* input, uint32_t len) { // INCORRECT: Only checking if len > 0, not checking against buffer_size if (len > 0) { // This causes out of bounds write when len > buffer_size memcpy(ctx->data_buffer, input, len); return 0; } return -1; } // Trigger the vulnerability int trigger_vulnerability() { wlan_ap_driver_ctx_t* ctx = malloc(sizeof(wlan_ap_driver_ctx_t)); ctx->buffer_size = 256; // Actual buffer size ctx->data_buffer = malloc(256); ctx->flags = 0; // Attacker-controlled input larger than buffer uint32_t malicious_len = 1024; // Exceeds buffer_size uint8_t* malicious_data = malloc(malicious_len); memset(malicious_data, 0x41, malicious_len); // Fill with 'A' // Trigger out of bounds write int result = vulnerable_write(ctx, malicious_data, malicious_len); // Cleanup free(malicious_data); free(ctx->data_buffer); free(ctx); return result; } int main() { printf("CVE-2025-20738 PoC - MediaTek WLAN AP Driver OOB Write\n"); printf("This PoC demonstrates the incorrect bounds check vulnerability.\n"); printf("In real scenario, this requires system-level access to trigger.\n"); trigger_vulnerability(); return 0; } /* * Exploitation Steps: * 1. Attacker gains initial system access (via other vulnerability) * 2. Load malicious kernel module or interact with vulnerable driver * 3. Trigger vulnerable write function with oversized input * 4. Overwrite security-critical structures (token, ACL, function pointers) * 5. Escalate privileges to root/admin level */