Website security basic check list

Security

• It's a lot to digest but the OWASP development guide covers Web Site security from top to bottom.
• Know about SQL injection and how to prevent it.
• Never trust user input (cookies are user input too!).
• Use a slow hashing algorithm, such as bcrypt (time tested) or scrypt (even stronger, but newer) (1, 2), for storing passwords. (How To Safely Store A Password)
• Don't try to come up with your own fancy authentication system: it's such an easy thing to get wrong in subtle and untestable ways and you wouldn't even know it until after you're hacked.
• Know the rules for processing credit cards. (See this question as well)
• Use SSL/HTTPS for login and any pages where sensitive data is entered (like credit card info).
• How to resist session hijacking.
• Avoid cross site scripting (XSS).

http://programmers.stackexchange.com/questions/46716/what-should-a-developer-know-before-building-a-public-web-site

• Avoid cross site request forgeries (XSRF).
• Keep your system(s) up to date with the latest patches.
• Make sure your database connection information is secured.
• Keep yourself informed about the latest attack techniques and vulnerabilities affecting your platform.
• Read The Google Browser Security Handbook.
• Read The Web Application Hacker's Handbook.

10 Best HTML5 Sketching and Drawing Tools for Designers

http://smashinghub.com/10-best-html5-sketching-and-drawing-tools-for-designers.htm

How to deal with Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.

Failed to load viewstate.  The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request.  For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.

Do not add same kind user control twice with different name into same placeholder if Viewstate is Enabled

Weird bug, how to handle dynamically loaded user control events not firing on first click

For every usercontrol,  need to set  ID property before adding. And don’t use Guid

Control ctl = this.LoadControl("usercontrol.ascx");

ctl.ID = "ctl" + i.ToString();

Panel1.Controls.Add(ctl);

Security Guidelines: ASP.NET 2.0

http://msdn.microsoft.com/en-us/library/ms998258.aspx