diff --git a/contrib/win32/win32compat/misc.c b/contrib/win32/win32compat/misc.c
index 025abcc3f..3441ad6d9 100644
--- a/contrib/win32/win32compat/misc.c
+++ b/contrib/win32/win32compat/misc.c
@@ -1720,3 +1720,178 @@ cleanup:
 
 	return ret;
 }
+
+/* builds session commandline. returns NULL with errno set on failure, caller should free returned string */
+char* 
+build_session_commandline(const char *shell, const char* shell_arg, const char *command, int pty)
+{
+	enum sh_type { SH_CMD, SH_PS, SH_WSL_BASH, SH_CYGWIN, SH_OTHER } shell_type = SH_OTHER;
+	enum cmd_type { CMD_OTHER, CMD_SFTP, CMD_SCP } command_type = CMD_OTHER;
+	char *progdir = w32_programdir(), *cmd_sp = NULL, *cmdline = NULL, *ret = NULL, *p;
+	int len, progdir_len = (int)strlen(progdir);
+
+#define CMDLINE_APPEND(P, S)		\
+do {					\
+	int _S_len = (int)strlen(S);		\
+	memcpy((P), (S), _S_len);	\
+	(P) += _S_len;			\
+} while(0)
+
+	/* get shell type */
+	if (strstr(shell, "system32\\cmd"))
+		shell_type = SH_CMD;
+	else if (strstr(shell, "powershell"))
+		shell_type = SH_PS;
+	else if (strstr(shell, "system32\\bash"))
+		shell_type = SH_WSL_BASH;
+	else if (strstr(shell, "cygwin"))
+		shell_type = SH_CYGWIN;
+
+	/* special case where incoming command needs to be adjusted */
+	do {
+		/*
+		* identify scp and sftp sessions
+		* we want to launch scp and sftp executables from the same binary directory
+		* that sshd is hosted in. This will facilitate hosting and evaluating
+		* multiple versions of OpenSSH at the same time.
+		*
+		* currently we can only accomodate this for cmd.exe, since cmd.exe simply executes 
+		* its commandline without applying CRT or shell specific rules
+		*
+		* Ex.
+		* this works
+		*	cmd /c "c:\program files\sftp" -d
+		* this following wouldn't work in powershell, cygwin's or WSL bash unless we put
+		* some shell specific rules 
+		*	powershell -c "c:\program files\scp" -t
+		*	cygwin\bash -c "c:\program files\scp" -t
+		*	bash -c "c:\program files\scp" -t
+		* 
+		* for now, for all non-cmd shells, we launch scp and sftp-server directly -
+		*	shell -c "scp.exe -t"
+		* note that .exe extension and case matters for WSL bash
+		* note that double quotes matter for WSL and Cygwin bash, they dont matter for PS
+		*
+		* consequence - 
+		* for non-cmd shells - sftp and scp installation path is expected to be in machine wide PATH
+		* 
+		*/
+
+		int command_len;
+		const char *command_args = NULL;
+
+		if (!command)
+			break;
+		command_len = (int)strlen(command);
+
+		if (command_len >= 13 && _memicmp(command, "internal-sftp", 13) == 0) {
+			command_type = CMD_SFTP;
+			command_args = command + 13;
+		} else if (command_len >= 11 && _memicmp(command, "sftp-server", 11) == 0) {
+			command_type = CMD_SFTP;
+
+			/* account for possible .exe extension */
+			if (command_len >= 15 && _memicmp(command + 11, ".exe", 4) == 0)
+				command_args = command + 15;
+			else
+				command_args = command + 11;
+		} else if (command_len >= 3 && _memicmp(command, "scp", 3) == 0) {
+			command_type = CMD_SCP;
+
+			/* account for possible .exe extension */
+			if (command_len >= 7 && _memicmp(command + 3, ".exe", 4) == 0)
+				command_args = command + 7;
+			else
+				command_args = command + 3;
+		}
+
+		if (command_type == CMD_OTHER)
+			break;
+
+		len = 0;
+		len += progdir_len + 4; /* account for " around */
+		len += command_len + 4; /* account for possible .exe addition */
+
+		if ((cmd_sp = malloc(len)) == NULL) {
+			errno = ENOMEM;
+			goto done;
+		}
+
+		p = cmd_sp;
+
+		if (shell_type == SH_CMD) {
+
+			CMDLINE_APPEND(p, "\"");
+			CMDLINE_APPEND(p, progdir);
+
+			if (command_type == CMD_SCP)
+				CMDLINE_APPEND(p, "\\scp.exe\"");
+			else
+				CMDLINE_APPEND(p, "\\sftp-server.exe\"");
+
+		} else {
+			if (command_type == CMD_SCP)
+				CMDLINE_APPEND(p, "scp.exe");
+			else
+				CMDLINE_APPEND(p, "sftp-server.exe");
+		}
+
+		CMDLINE_APPEND(p, command_args);
+		*p = '\0';
+		command = cmd_sp;
+	} while (0);
+
+	len = 0;
+	if (pty)
+		len += progdir_len + (int)strlen("ssh-shellhost.exe") + 5;
+	len +=(int) strlen(shell) + 3;/* 3 for " around shell path and trailing space */
+	if (command) {
+		len += 15; /* for shell command argument, typically -c or /c */
+		len += (int)strlen(command) + 5; /* 5 for possible " around command and null term*/
+	}
+	
+	if ((cmdline = malloc(len)) == NULL) {
+		errno = ENOMEM;
+		goto done;
+	}
+
+	p = cmdline;
+	if (pty) {
+		CMDLINE_APPEND(p, "\"");
+		CMDLINE_APPEND(p, progdir);
+		CMDLINE_APPEND(p, "\\ssh-shellhost.exe\" ");
+	}
+	CMDLINE_APPEND(p, "\"");
+	CMDLINE_APPEND(p, shell);
+	CMDLINE_APPEND(p, "\"");
+	if (command) {
+		if (shell_arg) {
+			CMDLINE_APPEND(p, " ");
+			CMDLINE_APPEND(p, shell_arg);
+			CMDLINE_APPEND(p, " ");
+		}
+		else if (shell_type == SH_CMD)
+			CMDLINE_APPEND(p, " /c ");
+		else
+			CMDLINE_APPEND(p, " -c ");
+
+		/* bash type shells require " decoration around command*/
+		if (shell_type == SH_WSL_BASH || shell_type == SH_CYGWIN)
+			CMDLINE_APPEND(p, "\"");
+
+		CMDLINE_APPEND(p, command);
+
+		if (shell_type == SH_WSL_BASH || shell_type == SH_CYGWIN)
+			CMDLINE_APPEND(p, "\"");
+	}
+	*p = '\0';
+	ret = cmdline;
+	cmdline = NULL;
+done:
+	if (cmd_sp)
+		free(cmd_sp);
+	if (cmdline)
+		free(cmdline);
+
+	return ret;
+}
\ No newline at end of file
diff --git a/contrib/win32/win32compat/misc_internal.h b/contrib/win32/win32compat/misc_internal.h
index 24fa9001a..1bc815312 100644
--- a/contrib/win32/win32compat/misc_internal.h
+++ b/contrib/win32/win32compat/misc_internal.h
@@ -54,3 +54,4 @@ int is_absolute_path(const char *);
 int file_in_chroot_jail(HANDLE, const char*);
 PSID get_user_sid(char*);
 int am_system();
+char* build_session_commandline(const char *, const char *, const char *, int );
diff --git a/contrib/win32/win32compat/pwd.c b/contrib/win32/win32compat/pwd.c
index a1793a247..04a764d2d 100644
--- a/contrib/win32/win32compat/pwd.c
+++ b/contrib/win32/win32compat/pwd.c
@@ -94,6 +94,7 @@ set_defaultshell()
 		if ((command_option_local = utf16_to_utf8(option_buf)) == NULL)
 			goto cleanup;
 
+	convertToBackslash(pw_shellpath_local);
 	pw_shellpath = pw_shellpath_local;
 	pw_shellpath_local = NULL;
 	shell_command_option = command_option_local;
diff --git a/regress/unittests/win32compat/miscellaneous_tests.c b/regress/unittests/win32compat/miscellaneous_tests.c
index 7f54023b2..bbddf24a9 100644
--- a/regress/unittests/win32compat/miscellaneous_tests.c
+++ b/regress/unittests/win32compat/miscellaneous_tests.c
@@ -311,6 +311,137 @@ test_chroot()
 	//_wsystem(L"RD /S /Q chroot-testdir >NUL 2>&1");
 }
 
+void
+test_build_session_commandline()
+{
+	char *progdir = w32_programdir(), *out, buf[PATH_MAX*2], shellhost_path[PATH_MAX];
+	shellhost_path[0] = '\0';
+	strcat(shellhost_path, "\"");
+	strcat(shellhost_path, progdir);
+	strcat(shellhost_path, "\\ssh-shellhost.exe\"");
+	int shellhost_path_len = (int)strlen(shellhost_path);
+
+	TEST_START("default interactive session tests");
+	out = build_session_commandline("c:\\system32\\cmd.exe", NULL, NULL, 0);
+	ASSERT_STRING_EQ(out, "\"c:\\system32\\cmd.exe\"");
+	out = build_session_commandline("c:\\system32\\cmd.exe", NULL, NULL, 1);
+	ASSERT_STRING_EQ(out + shellhost_path_len + 1, "\"c:\\system32\\cmd.exe\"");
+	out[shellhost_path_len] = '\0';
+	ASSERT_STRING_EQ(out, shellhost_path);
+	TEST_DONE();
+
+	TEST_START("cmd shell tests");
+	buf[0] = '\0';
+	strcat(buf, "\"c:\\system32\\cmd.exe\" /c \"");
+	strcat(buf, progdir);
+	int len_pg = strlen(buf);
+	out = build_session_commandline("c:\\system32\\cmd.exe", NULL, "internal-sftp -arg", 0);
+	buf[len_pg] = '\0';
+	strcat(buf, "\\sftp-server.exe\" -arg");
+	ASSERT_STRING_EQ(out, buf);
+	out = build_session_commandline("c:\\system32\\cmd.exe", NULL, "SFTP-server.exe -arg", 0);
+	buf[len_pg] = '\0';
+	strcat(buf, "\\sftp-server.exe\" -arg");
+	ASSERT_STRING_EQ(out, buf);
+	out = build_session_commandline("c:\\system32\\cmd.exe", NULL, "sftp-SERVER -arg", 0);
+	buf[len_pg] = '\0';
+	strcat(buf, "\\sftp-server.exe\" -arg");
+	ASSERT_STRING_EQ(out, buf);
+	out = build_session_commandline("c:\\system32\\cmd.exe", NULL, "sCp -arg", 0);
+	buf[len_pg] = '\0';
+	strcat(buf, "\\scp.exe\" -arg");
+	ASSERT_STRING_EQ(out, buf);
+	out = build_session_commandline("c:\\system32\\cmd.exe", NULL, "mycommand -arg", 1);
+	ASSERT_STRING_EQ(out + shellhost_path_len + 1, "\"c:\\system32\\cmd.exe\" /c mycommand -arg");
+	out[shellhost_path_len] = '\0';
+	ASSERT_STRING_EQ(out, shellhost_path);
+	free(out);
+
+	TEST_DONE();
+	
+	TEST_START("wsl bash shell tests");
+	out = build_session_commandline("c:\\system32\\bash.exe", NULL, "internal-sftp -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\system32\\bash.exe\" -c \"sftp-server.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\system32\\bash", NULL, "internal-sftp -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\system32\\bash\" -c \"sftp-server.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\system32\\bash", NULL, "sFTP-server -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\system32\\bash\" -c \"sftp-server.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\system32\\bash", NULL, "scP -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\system32\\bash\" -c \"scp.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\system32\\bash", "-custom", "mycommand -arg", 1);
+	ASSERT_STRING_EQ(out + shellhost_path_len + 1, "\"c:\\system32\\bash\" -custom \"mycommand -arg\"");
+	out[shellhost_path_len] = '\0';
+	ASSERT_STRING_EQ(out, shellhost_path);
+	free(out);
+	TEST_DONE();
+
+	TEST_START("cygwin bash shell tests");
+	out = build_session_commandline("c:\\cygwin\\bash.exe", NULL, "internal-sftp -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\cygwin\\bash.exe\" -c \"sftp-server.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\cygwin\\bash", NULL, "sftp-server -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\cygwin\\bash\" -c \"sftp-server.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\cygwin\\bash", NULL, "sftp-seRVer.exe -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\cygwin\\bash\" -c \"sftp-server.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\cygwin\\bash", NULL, "sCp -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\cygwin\\bash\" -c \"scp.exe -arg\"");
+	free(out);
+	out = build_session_commandline("c:\\cygwin\\bash", "-custom", "mycommand -arg", 1);
+	ASSERT_STRING_EQ(out + shellhost_path_len + 1, "\"c:\\cygwin\\bash\" -custom \"mycommand -arg\"");
+	out[shellhost_path_len] = '\0';
+	ASSERT_STRING_EQ(out, shellhost_path);
+	free(out);
+	TEST_DONE();
+
+	TEST_START("powershell shell tests");
+	out = build_session_commandline("c:\\powershell.exe", NULL, "internal-sftp -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\powershell.exe\" -c sftp-server.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\powershell", NULL, "sftp-server -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\powershell\" -c sftp-server.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\powershell.exe", NULL, "sftp-sERver.exe -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\powershell.exe\" -c sftp-server.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\powershell.exe", NULL, "scP -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\powershell.exe\" -c scp.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\powershell.exe", "-custom", "mycommand -arg", 1);
+	ASSERT_STRING_EQ(out + shellhost_path_len + 1, "\"c:\\powershell.exe\" -custom mycommand -arg");
+	out[shellhost_path_len] = '\0';
+	ASSERT_STRING_EQ(out, shellhost_path);
+	free(out);
+	TEST_DONE();
+
+
+	TEST_START("other shell tests");
+	out = build_session_commandline("c:\\myshell.exe", NULL, "internal-sftp -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\myshell.exe\" -c sftp-server.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\myshell", NULL, "sftp-server -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\myshell\" -c sftp-server.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\myshell", NULL, "sftp-seRVer.exe -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\myshell\" -c sftp-server.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\myshell", NULL, "sCp -arg", 0);
+	ASSERT_STRING_EQ(out, "\"c:\\myshell\" -c scp.exe -arg");
+	free(out);
+	out = build_session_commandline("c:\\myshell", "-custom", "mycommand -arg", 1);
+	ASSERT_STRING_EQ(out + shellhost_path_len + 1, "\"c:\\myshell\" -custom mycommand -arg");
+	out[shellhost_path_len] = '\0';
+	ASSERT_STRING_EQ(out, shellhost_path);
+	free(out);
+	TEST_DONE();
+}
+
+
 void
 miscellaneous_tests()
 {
@@ -321,4 +452,5 @@ miscellaneous_tests()
 	test_realpath();
 	test_statvfs();
 	test_chroot();
+	test_build_session_commandline();
 }
diff --git a/session.c b/session.c
index 682e0e25d..1b8cdeaca 100644
--- a/session.c
+++ b/session.c
@@ -468,13 +468,15 @@ setup_session_vars(Session* s)
 	wchar_t *pw_dir_w = NULL, *tmp = NULL;
 	char buf[256];
 	wchar_t wbuf[256];
-	char* laddr;
+	char *laddr, *c;
 	int ret = -1;
 
 	struct ssh *ssh = active_state; /* XXX */
 
 	UTF8_TO_UTF16_WITH_CLEANUP(pw_dir_w, s->pw->pw_dir);
-	UTF8_TO_UTF16_WITH_CLEANUP(tmp, s->pw->pw_name);
+	/* skip domain part (if there) while setting USERNAME */
+	c = strchr(s->pw->pw_name, '\\');
+	UTF8_TO_UTF16_WITH_CLEANUP(tmp, c ? c + 1 : s->pw->pw_name);
 	SetEnvironmentVariableW(L"USERNAME", tmp);
 	if (s->display) {
 		UTF8_TO_UTF16_WITH_CLEANUP(tmp, s->display);
@@ -527,15 +529,15 @@ cleanup:
 	return ret;
 }
 
-char* w32_programdir();
 int register_child(void* child, unsigned long pid);
+char* build_session_commandline(const char *, const char *, const char *, int);
 
 int do_exec_windows(struct ssh *ssh, Session *s, const char *command, int pty) {
 	int pipein[2], pipeout[2], pipeerr[2], r, ret = -1;
-	char *progdir = w32_programdir();
 	wchar_t *exec_command_w = NULL;
-	char  *command_enhanced = NULL, *exec_command = NULL;
+	char *exec_command = NULL;
 	HANDLE job = NULL;
+	extern char* shell_command_option;
 	
 	/* Create three pipes for stdin, stdout and stderr */
 	if (pipe(pipein) == -1 || pipe(pipeout) == -1 || pipe(pipeerr) == -1) 
@@ -568,119 +570,12 @@ int do_exec_windows(struct ssh *ssh, Session *s, const char *command, int pty) {
 	if (!in_chroot)
 		chdir(s->pw->pw_dir);
 
-#define CMDLINE_APPEND(P, S)		\
-do {					\
-	int _S_len = strlen(S);		\
-	memcpy((P), (S), _S_len);		\
-	(P) += _S_len;			\
-} while(0)
+	if (s->is_subsystem >= SUBSYSTEM_INT_SFTP_ERROR)
+		command = "echo This service allows sftp connections only.";
 
-	/* special cases where incoming command needs to be adjusted */
-	do {
-		if (s->is_subsystem >= SUBSYSTEM_INT_SFTP_ERROR) {
-			command = "echo This service allows sftp connections only.";
-			break;
-		}
-
-		/* if scp or sftp - add module path if command is not absolute */
-		if (s->is_subsystem || (command && memcmp(command, "scp", 3) == 0)) {
-			int en_size;
-			char* p;
-
-			if (!command || command[0] == '\0') {
-				error("expecting command for subsystem or scp");
-				errno = EOTHER;
-				return -1;
-			}
-
-			/* if absolute skip further logic */
-			if (command[1] == ':')
-				break;
-
-			/* account for max possible enhanced path */
-			en_size = PATH_MAX + 1 + strlen(command) ;
-			if ((command_enhanced = malloc(en_size)) == NULL) {
-				errno = ENOMEM;
-				goto cleanup;
-			}
-
-			p = command_enhanced;
-			CMDLINE_APPEND(p, progdir);
-			CMDLINE_APPEND(p, "\\");
-			
-			/* since Windows does not support fork, launch sftp-server.exe for internal_sftp */
-			if (IS_INTERNAL_SFTP(command)) {
-				CMDLINE_APPEND(p, "sftp-server.exe");
-				/* add subsystem arguments if any */
-				CMDLINE_APPEND(p, command + strlen(INTERNAL_SFTP_NAME));
-			} else
-				CMDLINE_APPEND(p, command);
-			
-			*p = '\0';
-
-			command = command_enhanced;
-			break;
-		}
-	} while (0);
-
-	/* build command line to be executed */
-	{
-		/* max possible cmdline size - account for shellhost path, shell path and command */
-		int max_cmdline_size = 2 * PATH_MAX + (command ? strlen(command) + 1 : 1) + 1;
-		char* p;
-		enum sh_type { SH_CMD, SH_PS, SH_BASH, SH_OTHER } shell_type = SH_OTHER;
-		extern char* shell_command_option;
-
-		if ((exec_command = malloc(max_cmdline_size)) == NULL) {
-			errno = ENOMEM;
-			goto cleanup;
-		}
-
-		p = exec_command;
-
-		if (strstr(s->pw->pw_shell, "system32\\cmd.exe"))
-			shell_type = SH_CMD;
-		else if (strstr(s->pw->pw_shell, "powershell"))
-			shell_type = SH_PS;
-		else if (strstr(s->pw->pw_shell, "bash"))
-			shell_type = SH_BASH;
-		else if (strstr(s->pw->pw_shell, "cygwin"))
-			shell_type = SH_BASH;
-
-		/* build command line */
-		/* For PTY - launch via ssh-shellhost.exe */
-		if (pty) {
-			CMDLINE_APPEND(p,"\"");
-			CMDLINE_APPEND(p, progdir);
-			CMDLINE_APPEND(p, "\\ssh-shellhost.exe\" ");
-		}
-
-		/* Add shell */
-		CMDLINE_APPEND(p, "\"");
-		CMDLINE_APPEND(p, s->pw->pw_shell);
-		CMDLINE_APPEND(p, "\"");
-		
-		/* Add command option and command*/
-		if (command) {
-			if (shell_command_option) {
-				CMDLINE_APPEND(p, " ");
-				CMDLINE_APPEND(p, shell_command_option);
-				CMDLINE_APPEND(p, " ");
-			} else if (shell_type == SH_CMD)
-				CMDLINE_APPEND(p, " /c ");
-			else
-				CMDLINE_APPEND(p, " -c ");
-
-			if (shell_type == SH_BASH)
-				CMDLINE_APPEND(p, "\"");
-
-			CMDLINE_APPEND(p, command);
-
-			if (shell_type == SH_BASH)
-				CMDLINE_APPEND(p, "\"");
-		}
-		*p = '\0';
-	}
+	exec_command = build_session_commandline(s->pw->pw_shell, shell_command_option, command, pty);
+	if (exec_command == NULL)
+		goto cleanup;
 
 	/* start the process */
 	{
@@ -760,8 +655,6 @@ do {					\
 	ret = 0;
 
 cleanup:
-	if (!command_enhanced)
-		free(command_enhanced);
 	if (!exec_command)
 		free(exec_command);
 	if (!exec_command_w)