Application Hardening Checklist

Guidelines to lowering the risk of a system intrusion because of an application flaw.

Applications are the most difficult parts of an IT infrastructure to secure because of their complexity and because they often need to accept input from a variety of users. Here are guidelines to lowering the risk of a system intrusion because of an application flaw:
  • Assume all installed applications are flawed—dont rely on the security programmed into them.
  • Physically remove from the system all applications not being used.
  • Use firewalls, content filters and OS user authentication features to restrict access to the application, and provide access only to those who absolutely must have it.
  • Update all applications to the latest patches when security bulletins are released.
  • Internally developed applications need to be code-reviewed for security weaknesses. Consider an external security review for critical applications.
  • Externally facing Web applications are high-risk applications because they are a bridge between the outside world and internal customer databases. Be sure to add code that can block or otherwise safely deal with all of the following hostile inputs: missing page parameters, parameters that are unusually long, parameters will nulls or hexadecimal encoding, parameters with Web browser script blocks (which are used to create server-side scripting attacks), and parameters with quotes and semicolons (likely attempts to send hostile SQL commands through to the database).
  • If possible, write applications in languages that run in virtual machines--such as Java, Visual Basic .Net or C#--because they provide an extra layer of security protection. Avoid C and C++ because they make it easy to write applications that allow buffer overflow attacks.

Also in this Special Report

  • Ignorance: The Hackers Best Friend
  • Security Roundtable
  • Here Be Dragons: Web Services Risks
  • Threats to Come
  • Trail of Destruction: The History of the Virus
  • Community Builds Security: Labs Answers Your Security Questions
  • WLAN Hardening Checklist
  • Operating System Hardening Tips