Security of code in view of disassembler - C# Discussion Boards

Re: virus over network layer

22-Mar-05 23:22

What does this have to do with C#?

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Giles23-Mar-05 8:49

Giles

23-Mar-05 8:49

He wants to know how to write a virus in c# that distributes itself in C#!!!!

Its simple. Laugh | :laugh:

POLICE!!!!!

Re: virus over network layer

leppie23-Mar-05 11:17

Security of code in view of disassembler

23-Mar-05 11:17

I wonder if it will download and install the .NET runtime as well, before executing itself. Poke tongue | ;-P

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Rama Sharma22-Mar-05 20:56

Rama Sharma

22-Mar-05 20:56

One can disassemble the code of an assembly (in say Visual C# language) complied by using Visual Studio .NET even if it is a Release build. This can be done by using the disassembler "ILDASM.EXE" provided with the VS .NET . It shows all details of the code giving vivid details of all methods, properties, fields, classes, structs, etc. What then is the security of a complied assembly which is in the MSIL version? Tomorrow, anybody can copy your idea and may be even replace some portions of the compiled file, such as the code security portions. Can anyone explain as to whether there is some way out to ensure that a particular assembly could not be disassembled using the aforesaid disassembler or some other similar utility. (here I may point out that an assembly converted to native code by using ngen.exe is only a partial solution in as much as the resultant file cannot be stored in the application directory but is stored in the protected catche). Any solutions or comments? Smile | :)

Re: Security of code in view of disassembler

leppie22-Mar-05 22:42

how to check password and user name

22-Mar-05 22:42

You cant prevent disassembly, but you can make reassembly very hard. You can use an obfuscator (but thats really just designed to keep the idiots away), release (iow optimized) builds help too. Have only the least accesible modifiers on classes and members. Another is to make sure you sign all assemblies. If you place your 'security' code in a signed assembly that all your other assemblies depends on, ALL assemblies would have to be altered (resigned) to reconstruct the program. At this point most people says "stuff it" :p

With all that said, I have only seen 1 (one) .NET program that didnt seem 'crackable'. I will not give you details. Smile | :)

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Aleyna22-Mar-05 20:38

Aleyna

22-Mar-05 20:38

Hi Im currently creating a login form and i want to check if the input user name and password matches the data in the database. I have created a table called Users in my database, that contains two columns user name and password. I have declared my sql command text to the sql string and filled my dataset. I then created if else statement such as:
if(username_txt.Text == loginDS1.login.UserNameColumn.ToString() && password_txt.Text == loginDS1.login.PasswordColumn.ToString()
{
main_frm main_frm = new main_frm();
main_frm.Show();
}
else
MessageBox.Show("Incorrect username and password!");

Im a new starter and i really dont know the correct technics however i really need want to learn..... Help!!! Cry | :((

Re: how to check password and user name

Jeff Martin23-Mar-05 3:47

Jeff Martin

23-Mar-05 3:47

A few things to consider...

Make sure to use a parameterized query (preferably a stored proc) instead of just a plain query string. I.e.

cmd.CommandText = "usp_GetUserInformation";
cmd.Parameters.Add("@userName", userName); //from username_txt.Text

instead of ...

cmd.CommandText = "select UserName, Password from Users where UserName = '" + username_txt.Text + "'";

The reason for this is to prevent SQL injection attacks.

Another thing...

Don't store the password in plain text in the database. When the user sets up the password, hash it and store the hash. Then when checking the password, hash what they enter the same way and compare it to what is in the db.

Jeff Martin
My Blog

How to read system time?

Kiran Satish22-Mar-05 20:28

Kiran Satish

22-Mar-05 20:28

Hi all,
I need to read the system time and write it to text file when ever the user presses some alphabet keys.

thanks for anykind of help,

Pavan.

Suman

My: Blog | Photos
WDevs.com - Open Source Code Hosting, Blogs, FTP, Mail and More

Colin Angus Mackay22-Mar-05 20:29

Colin Angus Mackay

22-Mar-05 20:29

DateTime.Now

Kiran Satish22-Mar-05 20:57

Kiran Satish

22-Mar-05 20:57

Hi,
thanks for ur reply... if u dont mind can u give me a precise command... i need to read the time upto milliseconds... like hh:mm:ss:ms.... i saw tht tickcounts will do tht but i didnt understand how to use it.

Can u please help me out on this....

Thanks in advance,

Pavan

J4amieC23-Mar-05 2:35

J4amieC

23-Mar-05 2:35

how about this.

DateTime[^]

FileStream[^]

You have to start by reading the docs, right?

There are code examples and useful links in both the above docs, if and when you get stuck on a particular part please post again.

Kiran Satish23-Mar-05 9:44

Kiran Satish

23-Mar-05 9:44

thanks for ur links, i do have gone through them. But i didnt get how to read the time upto NANO or MILLI seconds at the particular instance when we press a specified key on the keyboard, which is the only problem i am having.

I want the format to be like... hh:mm:ss:ms (where ms is milliseconds)

The millisecond property is not related to the system time while it is related to the instance of the application.

it would be greatful if anyone can help me on tht.

thanks,

Suman

Bitmaps

Beringer22-Mar-05 18:01

Beringer

22-Mar-05 18:01

Does anybody know where I can get modern looking bitmaps for commonly used buttons like Bold, Italic, Underline, Undo/Redo, etc.?

Thanks
Eric

Re: Bitmaps

leppie22-Mar-05 23:24

Strange "MessageBox" Behavior

22-Mar-05 23:24

Do what I do, get your ex girlfriend to do them for you Laugh | :laugh:

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Re: Bitmaps

Judah Gabriel Himango23-Mar-05 6:05

Judah Gabriel Himango

23-Mar-05 6:05

I believe VS ships with a bunch of generic icons. Also, GNU art and other sites offer free icons.

Tech, life, family, faith: Give me a visit.
I'm currently blogging about: He has a funny face. And he's my son.
Judah Himango

Jethro6322-Mar-05 15:19

22-Mar-05 15:19

Hi:

I am currently going through a Wrox book "Professional C++, 2nd Edition". I have been typing in the example code myself and have encountered a strange problem.

Each time an example program uses a "MessageBox" call, the message box is launched, but there is no print on it. The button is there, and it works as expected when you click it but there is no text on the box window OR the push-button.

As a sanity check, I created a basic Windows App using the app wizard. I made one single change to the code: In the constructor for Form1, right after the call to "InitializeComponents", I added the line:

MessageBox("Hello ?");

Same result.

I am using Visual Studio.NET V7.0 with .NET Framework 1.1.4322 SP1. I am running on Windows XP-Pro with all of the latest service packs. I have also transfered the executable code from some of these programs to another machine with the same results.

Has anybody out there had this problem? Any idea what might be going on?

Thanks in advance for you help
Mark

Nick Parker22-Mar-05 16:38

Nick Parker

22-Mar-05 16:38

I can't say that I've ever seen that, but can you confirm, what language are you working in? You said the book you are reading is "Professional C++, 2nd Edition", this is the C# forum. From the looks of your code it does appear to be C++, however you should check the function parameters. The following example I threw together works fine in Visual Studio .NET 2003 using unmanaged C++.

#include "stdafx.h"
#include <windows.h>

int _tmain(int argc, _TCHAR* argv[])
{
	MessageBox(NULL, "Hello", "Test", MB_OK);
	return 0;
}

- Nick Parker
Microsoft MVP - Visual C#
My Blog | My Articles

Jethro6323-Mar-05 2:25

23-Mar-05 2:25

Hi Nick:

Sorry, that was a typo. It IS C# I am talking about and the book is "Professional C#, 2nd Edition."

I have worked through examples where I launch the MessageBox from a push-button handler, from event handlers and event from simple console applications, similar to what you have done above but in C# of course. I get the same result.

In fact, here's a console program that I used:

using System;

namespace Learn.CSharp.MessageBoxTest<br />
{<br />
class	MainEntryPoint<br />
{<br />
	public static void Main()<br />
	{<br />
	MessageBox.Show( "Console App", "Hello there!", MessageBoxButtons.OK );<br />
	}<br />
}<br />
}

Any ideas?
Thanks,
Mark

Nick Parker23-Mar-05 5:08

Nick Parker

23-Mar-05 5:08

The MessageBox class is defined within the System.Windows.Forms namespace. Assuming that your project has already included a reference to the appropriate assembly, just include it in the using statement:

using System;
using System.Windows.Forms;

namespace Learn.CSharp.MessageBoxTest
{
	class MainEntryPoint
	{
		public static void Main()
		{
			MessageBox.Show("Console App", "Hello there!", MessageBoxButtons.OK);
		}
	}
}

- Nick Parker
Microsoft MVP - Visual C#
My Blog | My Articles

Jethro6324-Mar-05 2:59

24-Mar-05 2:59

Hi Nick:

The code snippet I provided was missing the "using System.Windows.Forms;" statement but the program I was running was not. The exact program that you recommend in your last response still has the same problem....

Regards,
Mark

Jethro637-Apr-05 2:04