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Load an EXE File and Run It from Memory

, 24 Apr 2006
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Simple application to load an EXE file and run it from memory (only for .NET compiled files)

Introduction

This example shows how to load an application and run it from the memory system. After the application load, you can use it without the source EXE file (usually blocked from the system). This is useful when you don't need to have the source EXE file on HDD (e.g. on a USB key).

Using the Code

This example is divided into two simple steps:

  1. The binary reading of the EXE file
  2. Its loading into the Assembly cache of the read result

First Step

Load the EXE file in one stream and read it as an array of bytes:

// read the bytes from the application EXE file
FileStream fs = new FileStream(filePath, FileMode.Open);
BinaryReader br = new BinaryReader(fs);
byte[] bin = br.ReadBytes(Convert.ToInt32(fs.Length));
fs.Close();
br.Close();

Using the FileStream class, it is possible to open the EXE file (location indicated in the filePath variable), read and close it to release resources.

Second Step

Use the Assembly.Load method to load the EXE file (as array of bytes) into the Assembly cache:

// load the bytes into Assembly
Assembly a = Assembly.Load(bin);
Now we can try to find the entry point of the application:
// search for the Entry Point
MethodInfo method = a.EntryPoint;
if (method != null) {
...
}

If an entry point is found, is possible to create an instance of the application Main method and invoke it from our application launcher:

// create an instance of the Startup form Main method
object o = a.CreateInstance(method.Name);
// invoke the application starting point
method.Invoke(o, null);

If all will be ok, the called application will start without using the source EXE file (try to move it to check).

In the demo project zip file, I put a simple application launches one EXE file found in the same folder of the launcher EXE. If there are more than one files, a request file Form starts to ask the user which file to select from the folder.

NOTE: Pay attention to the Application.SetCompatibleTextRenderingDefault method of the called application. Visual Studio 2005 applies this line in the Main method (located inside the Program.cs file) to use the new GDI+ library in our applications, but it will throw an exception because it must be called before the first IWin32Window object is created.

History

  • 24th April, 2006: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Gianni Marzaloni (ZofM)
Web Developer HTML.it
Italy Italy
Simple C# Developer.

Comments and Discussions

 
GeneralMy vote of 5 PinmemberPaulo Zemek1-Apr-13 9:36 
QuestionThis doesn't work with WPF projects [modified] Pinmemberclemsy1-Apr-13 9:11 
Generalit can not run a vb.net exe Pinmemberon-raptor15-Jul-10 8:53 
QuestionIt's posible in vb6 ? Pinmemberdbonet11-Nov-09 5:23 
GeneralOk, problem solved PinmemberMember 35098543-Feb-09 6:56 
Generaljava Pinmembert3dysu29-Nov-08 0:35 
GeneralRe: java PinmemberMember 35098543-Feb-09 7:20 
General"Could not load file or assembly" Pinmembernjuneardave31-Jul-08 9:28 
GeneralRe: "Could not load file or assembly" Pinmemberclemsy30-Mar-13 5:49 
QuestionWhy is this necessary? PinmemberPIEBALDconsult3-Apr-08 17:47 
AnswerTHIS IS USEFUL! [modified] Pinmembersebastiannielsen2-Jul-08 10:22 
This is EXTREMELY useful.
 
Just think: Load the target EXE into a byte array. Then encrypt it with System.Security.Cryptography.Rijndaelmanaged using a sha256 of the password as key, and then convert the encrypted EXE to a base64 string.
 
Then you can make a new project, hard code the base64 string and have a password promt. Then the password decrypt the EXE, and run it from memory as described here. Everything is done in a Try...Catch...End Try block so if wrong password is supplied then it can "MsgBox" the user about it.
 
This can also be used to build a Anti-Piracy wrapper for a application by encrypting it with a key that is a result from a calculation on a valid CD-key. Incorrect CD-key = the application wont decrypt.
 
Also you can use this to fetch a encrypted EXE from a server and then decrypt it in-memory with a hard-coded key. Now updating has never been as easy as putting your updated EXE into your webspace and Voilá, the application is up2date for everyone that has previously downloaded your application.
This could also be used in Anti-Piracy situations, by just having a CGI script to encrypt your EXE with the supplied serial number as key, and then the target application who downloaded the encrypted EXE decryptes it using the serial as key.
 
Of course you have a hard coded "salt" value in the application so not anybody with the correct serial can decrypt for themselves.
Then if you see that a specific serial is used at multiple places, just ban that serial and your application can never be used by that serial any longer, since the client application can no longer download the encrypted EXE.
 
Another fun thing you can do if you let your client fetch the EXE from the internet, is that if the serial in question is marked as piracy, you could make your server send a encrypted variant of some software that install itself in startup and keylog, screenlog, and records sound from attached mic and take some snaps if theres a webcam. Then stuff everything in a packet and then into your server, that will log IP & time too.
 
Its s simple matter of prosecuting that person for piracy after that, since you both have IP evidence and *image evidence*.
GeneralCMD Pinmemberkoushik_rebaca1-Sep-07 2:14 
GeneralHi Pinmembermezo_2225-Mar-07 10:35 
GeneralRe: Hi PinmemberMike_Silver_A20-Apr-09 5:41 
GeneralVB Demo (Load an exe file and run it from memory) PinmemberUlambayar14-Jan-07 2:47 
GeneralRe: VB Demo (Load an exe file and run it from memory) Pinmemberuyalksouiwh2-Apr-07 8:43 
GeneralRe: VB Demo (Load an exe file and run it from memory) PinmemberMacka00700725-Jul-07 21:14 
GeneralRe: VB Demo (Load an exe file and run it from memory) PinmemberSheridan10121-Nov-07 8:39 
QuestionHow to load exe compiled with /clr? Pinmembermartho210-Jan-07 3:14 
GeneralRun x.exe from y.exe without extracting from y.exe which is stored as resource PinmemberRahul A. H.29-Oct-06 20:00 
GeneralRe: Run x.exe from y.exe without extracting from y.exe which is stored as resource PinmemberUlambayar14-Jan-07 2:42 
GeneralRe: Run x.exe from y.exe without extracting from y.exe which is stored as resource PinmemberUlambayar14-Jan-07 2:43 
GeneralRe: Run x.exe from y.exe without extracting from y.exe which is stored as resource PinmemberMike_Silver_A14-Jun-09 21:48 
GeneralRe: Run x.exe from y.exe without extracting from y.exe which is stored as resource PinmemberMike_Silver_A14-Jun-09 21:47 
GeneralCan't be used with all exe types PinmembernSerj24-Oct-06 9:41 

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