Malware

Malware: Malware, short for malicious software, consists of programming (code, scripts, active content, and other software) designed to disrupt or deny operation, gather information that leads to loss of privacy or exploitation, gain unauthorized access to system resources, and other abusive behavior.

A few examples of malware:

1. Virus: A computer program that can copy itself and infect a computer.

2. Worm: A self-replicating malware computer program, which uses a computer network to send copies of itself to other computers on the network.

3. Spyware: A malware that collects small pieces of information about users without their knowledge.

4. Adware: Any software package which automatically plays, displays, or downloads advertisements to a computer.

5. Trojan horse: A destructive program that masquerades as an application. The software initially appears to perform a desirable function for the user prior to installation, but steals information or harms the system.

6. Rootkits: Once a malicious program is installed on a system or a human attacker breaks into a computer, it is essential that it stays concealed, to avoid detection and disinfection. Techniques known as rootkits allow this concealment, by modifying the host's operating system so that the malware is hidden from the user. Rootkits can prevent a malicious process from being visible in the system's list of processes, or keep its files from being read.

7. Backdoors: It is a method of bypassing normal authentication procedures. Once a system has been compromised (by one of the above methods, or in some other way), one or more backdoors may be installed in order to allow easier access in the future. Backdoors may also be installed prior to malicious software, to allow attackers entry.

Configuring IIS - A name was started with an invalid character. Error processing resource.

If you are getting this error: "A name was started with an invalid character. Error processing resource" when you try to access your ASP.NET page after a fresh IIS installation,

Then, try to configure IIS by doing this this:

Go to RUN and type this:
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_regiis.exe -i

In some cases this also helps: In the IIS properties (by right clicking "Properties" of "Web Sites" under "IIS" in services), under the ASP.NET tab, the version of ASP.NET is not selected. Select one for your ASP.Net version.

Environment variables in C#

C# syntax:
To get the logged-in username:
string username = System.Environment.GetEnvironmentVariable("USERNAME");

To get the name of the client machine:
string machinename = Environment.MachineName;

C# - Difference between Convert and Parse

Convert.ToInt32(string) and Int32.Parse(string) yield identical results except when the string is actually a null. In this case, Int32.Parse(null) throws an ArgumentNullException; but, Convert.ToInt32(null) returns a zero.

Response.Redirect exception in .NET 2.0

In .NET 2.0, using Response.Redirect gives an exception,
"Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack."

To solve the problem, use:
Response.Redirect ("Success.aspx", false)

or to end the response, write,
Response.Redirect ("Success.aspx", true)

DOS - Tips for DATE and WINZIP

1. For printing DATE in DOS, we use DATE. The format in which the DATE is displayed varies from profile to profile. If you want to change the format of the date, then go to Control Panel>Regional and Language Options. Go to Regional Options tab and click on the Customize button. Go to the Date tab and change the way you want your date to be displayed. You can also change the Date format using the Date separator in the same tab.
Now go to the command prompt and type DATE to get the date display in the format you desire. This is particularly useful when you want to create a file with DATE in its name. If you have '\' in your date, there would be an error.

2. To winzip a file using DOS, locate your Zip exe. Generally, it is in 'Program Files'. Use the following syntax to zip all the .txt files in the folder F:\test. In this example below, we desire a zip file with the name beginning with Ru appended with today's date. So, the name of the zip file created on 03-19-2009 should be:
RuThu 03-19-2009.zip.
Syntax:
"C:\Program Files\WinZip\WZZIP" "F:\test\RU%DATE%.ZIP" F:\test\*.txt

Splitting string with Delimiter in SQL

DECLARE @FullTask VARCHAR(100)
SET @FullTask = 'Task1-Task2'

If you know there would always be Task2, then the syntax for getting Task1 and Task2 is:
SELECT SUBSTRING(@FullTask, 1, CHARINDEX('-', @FullTask) - 1) AS [FirstTask],
SUBSTRING(@FullTask, CHARINDEX('-', @FullTask) + 1, LEN(@FullTask)) AS [LastTask]

If there is no LastTask, that is @FullTask='Task1' then getting LastTask would give error.

To avoid the above error, the query would be:
SELECT SUBSTRING(@FullTask, 1, NULLIF(CHARINDEX('-', @FullTask) - 1, -1)) AS [FirstTask],
SUBSTRING(@FullTask, CHARINDEX('-', @FullTask) + 1, LEN(@FullTask)) AS [LastTask]

This can be used for any delimiter, even if the delimiter is a space as ' ' instead of a hyphen as '-' in the above example.