char buffer[256]; strcpy(buffer, telnet_option_string); // overflow
// Instead of HhapiOpen HANDLE hCom = CreateFile(L"\\\\.\\COM3", GENERIC_READ | GENERIC_WRITE, 0, nullptr, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, nullptr); // Configure DCB instead of hypertrm's internal settings DCB dcb = 0; dcb.BaudRate = CBR_9600; dcb.ByteSize = 8; SetCommState(hCom, &dcb); If you must reverse-engineer or patch hypertrm.dll for legacy system support: 6.1 Key Offsets (Windows XP SP3 version) | Function | RVA (hex) | Remarks | |----------|-----------|---------| | HhapiOpen | 0x00012A30 | Calls CreateFileA on COM port | | HhapiWrite | 0x00012F90 | Uses WriteFile synchronously | | Telnet IAC handler | 0x00018E40 | Vulnerable WILL/WONT parsing | | XMODEM CRC calc | 0x0001C520 | Custom table-based CRC | 6.2 Safe Patching Strategy To mitigate the known buffer overflow in Telnet option negotiation: hypertrm.dll
Report ID: HR-2024-001 Date: 2024-05-21 Subject: Dynamic Link Library (DLL) Analysis – HyperTerminal Core File Name: hypertrm.dll Status: Legacy Component / Security Risk (Archived) 1. Executive Summary hypertrm.dll is the core library for HyperTerminal , a terminal emulator originally bundled with Microsoft Windows operating systems from Windows 95 through Windows XP. It was removed from Windows Vista onward due to security vulnerabilities and lack of modern protocol support. ASLR: False DEP: False (NX disabled) SafeSEH: False
ASLR: False DEP: False (NX disabled) SafeSEH: False Authenticode: None GENERIC_READ | GENERIC_WRITE