Web Vulnerabilities_NGAN Seok Chern

WEBSITE VULNERABILITIES
Ngan Seok Chern
MCP | CEH | MVP – ASP / ASP.NET
seokchern85@hotmail.com
http://blog.scnetstudio.com

Agenda
 Web application setup
 Why attack
 Type of attack & countermeasure

Why Attack ?
 DefacingWebsite
 Sealing credit card information
 exploting server-side scripting
 exploiting buffer overflow
 and etc

Step
1. Scanning
2. Gather
Information
3.Testing
4. Plan
5. Launch

Type of Attack
 Cross-site Scripting / XSS Flaws
 SQL Injection
 Buffer Overflow
 DirectoryTraversal
 Error message interception attack
 Web.config
 and etc

Cross-site Scripting / XSS Flaws
 Typically found in web applications which allow
code injection by malicious users into the web
pages viewed by other users.
 JavaScript is commonly used.
 During an attack "everything looks fine" to the
end-user.
 <script> </script>
 Countermeasure :
 Validate all your sources.
 Filtering script output.

SQL Injection
 SQL to manipulate database’s data
 Execute from address bar, queries /
searches.
 SELECT fieldlist FROM table
WHERE field = '$EMAIL';
 SELECT fieldlist FROM table
WHERE field = 'anything' OR
'x'='x';
 Countermeasure:
 Check user input.
 Validate and sanitize user input that
passed to database.

Buffer Overflow
 Where a process stores data in a buffer
outside the memory the programmer set
aside for it.
 Countermeasure:
 Validate input length.
 Check and pay extra care on loop function which
carry data.

Directory Traversal
 Attacker able to browse directories
and files.
 Expose the directory structure of
application and often the underlying
web server and operating system.
 Eg. “../Images/logo.gif”
 Countermeasure:
 Define access right to the protected area
 Apply checks/hot fixes
 Update web server with patches in timely
manner

Error Message Attack
 Based on error message that show.
 Example:
 Your password is incorrect.
 Connecting to the database on ……. With …..is not
unsuccessful.
 Countermeasure:
 Modify and display common error message.

Web.config
 Connection String Information
 Example:
 Data Source=190.190.200.100,1433;Network
Library=DBMSSOCN;Initial
Catalog=myDataBase;User
ID=myUsername;Password=myPassword;
 Countermeasure:
 Encrypt your web.config.
 aspnet_regiis.exe -pef "connectionStrings
Name" "C:InetpubwwwrootMySite" –prov
"DataProtectionConfigurationProvider”

Summary
 Programmer played important roles.
 Patches your server.

Web Vulnerabilities_NGAN Seok Chern

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