1. Computer Security and Penetration Testing
Chapter 13
Programming Exploits

2. Objectives Describe the evolution of programming exploits
Recognize vulnerabilities in ActiveX controls
Identify steps to counter vulnerabilities in ActiveX controls
Recognize vulnerabilities in VBScript
Identify steps to counter vulnerabilities in VBScript
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3. Objectives (continued)
Recognize vulnerabilities in HTML
Identify steps to counter vulnerabilities in HTML
Recognize vulnerabilities in Java and JavaScript
Identify steps to counter vulnerabilities in Java and JavaScript
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4. C and C++ Vulnerabilities in the C and C++ Programming Languages.
- Buffer over-runs
- Failure to handle errors
- Improper file access
C and C++ Security Measures
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5. C and C++
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6. .NET Framework Vulnerabilities in the .NET Framework
- Cross-site scripting
- Integer overflow
Countering .NET Framework Vulnerabilities
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7. HTML5 Hypertext Markup Language (HTML) HTML is not a dynamic language
Most basic script used to develop Web pages
Uses a set of markup tags to define the structure of Web pages
Browsers represent pages by interpreting these tags
HTML is not a dynamic language
Cannot be executed successfully except within a Web browser
Computer Security and Penetration Testing

8. HTML5 (continued)
HTML is essentially bulletproof and benign as long as it is used to display static text
Arbitrary requirements for more finished and sophisticated pages
Have required the development of many more tags and formatting conventions
With increased complexity came increased opportunities for hackers to discover vulnerabilities
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9. Countering HTML5 Vulnerabilities
Make sure patches are up to date
Pay attention when new exploits are reported
Activate the automated patch management software
Turn off services and features that you
Know to be vulnerable to attack
Do not understand
Do not use
Avoid known dangerous sites by installing and updating security software
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10. Countering HTML5 Vulnerabilities (continued)
Secure transfer of data has been made available by protocols such as Secure Sockets Layer (SSL)
The way Internet Explorer handled SSL was discovered to be susceptible to a man-in-the-middle exploit
Generating random encryption keys of 40 or 128 bits in length has solved this problem
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11. Java and JavaScript
Java is a programming language that is compiled into applications or applets
Java applications are stand-alone applications
Run on the server or are downloaded to the client
JavaScript is a scripting language that runs between <script> tags in a Web page
A JavaScript cannot operate on its own, and is not compiled to run
Computer Security and Penetration Testing

12. Java
Object-oriented programming language (OOP) developed by Sun Microsystems
Designed to run in a platform-independent manner using Java Runtime Environment (JRE)
Installed on the client computer as its sandbox
In Java, each function is modularized
With this low-level modularization
There is less of a chance that updating one piece of the application will break other parts
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13. Java (continued)
Java was intended to be developed quickly with pretested parts
Java applets provide functionality on the Internet
Require Java-enabled browsers
Java is machine-safe
Can only act upon other objects within the JRE
Java has no access to write, modify, or delete files on the hard drive or to modify the operating system
Computer Security and Penetration Testing

14. JavaScript
Scripting language developed by Netscape Communications Corporation
Similar to VBScript in terms of implementation
Almost every browser on almost every platform is JavaScript-enabled
Like Java, requires a runtime environment
As a script, the network bandwidth and client-side memory resource use is less than that required for the larger and more robust Java
Computer Security and Penetration Testing

15. Security Vulnerabilities in Java
Vulnerabilities of Java:
Client-side malevolent applets
Server-side cross-scripting
Server-side address spoofing
A substantial percentage of vulnerabilities are related to vulnerabilities in the JRE
Which can result in applets arbitrarily giving themselves elevated privileges
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16. Security Vulnerabilities in Java (continued)
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17. Security Vulnerabilities in Java (continued)
Because Java is a platform-independent technology
Issues such as malevolent applets can be used against any platform that has the JRE installed
Client-side attacks include:
Attacks on file integrity
Buffer overflow
Storm attacks
Denial-of-service attacks
Disclosure attacks
Annoyance attacks
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18. Vulnerabilities in JavaScript
Vulnerabilities are similar to those in VBScript
JavaScript vulnerabilities allow:
Sending messages with information about the target computer to a client
Opening and closing applications on the target computer
Modifying files on the victim’s computer
Main threat posed by JavaScript
May be used to download components on a user’s computer without his or her knowledge
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19. Countering Java and JavaScript Vulnerabilities
Best preventative measure for an end user
Perform all updates as soon as they are available
Keep virus definitions in their antivirus or security program updated
Set the Internet Options Control Panel
To ask for permission before running JavaScripts or downloading Java applets
Check the authenticity of the validation signatures attached to applets and scripts
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20. Countering Java and JavaScript Vulnerabilities (continued)
Check for security of links available on the signed scripts
Programmers should develop and adhere to secure programming guidelines
And sign their scripts
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21. Summary
Programming exploits are the defects in various programming languages that are used to develop server-side and client-side applications
ActiveX controls are stand-alone compiled applications that make it possible to link and allow interactions between various applications
The design flaw in ActiveX is that it can do anything the user can do
Attackers can use ActiveX to modify resources on an implementation of Windows
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22. Summary (continued)
To safeguard against attacks, end users should install the most recent and stable version of Internet Explorer available
VBScript can be used within HTML tags to produce a dynamic HTML page
One of the most common exploits used on the Internet is a buffer overflow
If you are administering a network, do not allow use of IE or Outlook
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23. Summary (continued)
If you are the administrator of a Web site, run an antivirus application on your Web server to search for known bad ActiveX controls
Hypertext Markup Language (HTML) is the most basic script used to develop Web pages
The most effective way to counter HTML-related exploits is to keep up with the latest patches
Java and JavaScript languages
The best preventive measure for end users is to perform all updates as soon as they are available
Computer Security and Penetration Testing