Home > Ask the Security Experts > Information Security Threats Questions & Answers > To prevent cross-site scripting, should specific words and characters be rejected?
Ask The Security Expert: Questions & Answers
EMAIL THIS

To prevent cross-site scripting, should specific words and characters be rejected?

John Strand, featured expert EXPERT RESPONSE FROM: John Strand, featured expert

Pose a Question
Other Security Categories
Meet all Security Experts
Become an Expert for this site


Digg This!    StumbleUpon Toolbar StumbleUpon    Bookmark with Delicious Del.icio.us   


>
QUESTION POSED ON: 14 September 2008
I'm interested in preventing cross-site scripting (XSS) attacks. If we reject characters and words like <, >, script, -- and their equivalent entity values, etc., that can cause malicious attacks -- it increases the cost of application development. Would you recommend this course of action?

>
No. Instead, I recommend that developers code their applications to only allow the required set of characters necessary for the application to function properly. That is an application development best practice.

Many organizations view secure coding as an activity that is supposed to happen at the end of the development process. However, if someone testing an application at the end of the development lifecycle says an application needs recoding to ensure its security, that application will need to be reworked and retested, along with any other application that interacts with it. This constant tweaking is often far more expensive than implementing an iterative security process throughout an application development lifecycle.

If there is a field called "State," for example, there is no reason to allow <, > ;, *, --, or : as possible values. If application developers write code from the perspective of only accepting known good values, it decreases the overall cost of application development by cutting quality assurance and certification and accreditation testing.

For more help, a great framework to use is the Scalable & Agile Lifecycle Security for Applications.

More information:

  • Video: Security researchers at Information Security Decisions 2008 recently discussed how to keep enterprises safe from cross-site scripting and buffer overflows.


  • BROWSE BY TAG
    Information Security Threats,   Application and Platform Security,   Web Security Tools and Best Practices,   Web Application Security,   Application Attacks (Buffer Overflows, Cross-Site Scripting),   VIEW ALL TAGS

    Digg This!    StumbleUpon Toolbar StumbleUpon    Bookmark with Delicious Del.icio.us   



    RELATED CONTENT
    Information Security Threats
    How to get rid of malware, botnets on a hospital IT network
    Should a national cybersecurity strategy include offensive botnets?
    How can search results lead to malware?
    How to prevent brute force webmail attacks
    How to prevent mobile phone spying
    What are today's antivirus software trends?
    How to detect input validation errors and vulnerabilities
    Can secure USB devices prevent man-in-the middle attacks
    How to prevent and build protection against online identity theft
    Is there a spy on my mobile device?

    Web Application Security
    Preventing SQL injection attacks: A network admin's perspective
    Cisco acquires SaaS security vendor ScanSafe
    Web application firewall use goes beyond compliance, company finds
    Gumblar Trojan drive-by exploits spike following Adobe update
    Some Facebook applications lead to Russian attack sites
    Barracuda acquires Purewire expanding Web security reach
    An enterprise strategy for Web application security threats
    Scanning with N-Stalker offers basic Web application security assessment
    Attackers target PDF, DirectShow flaws with malicious banner ads
    New Bahama botnet evades search engines, fuels click fraud

    Application Attacks (Buffer Overflows, Cross-Site Scripting)
    Adobe warns of critical update for Reader, Acrobat 9.1.3
    9 Ways to Improve Application Security After an Incident
    Developers Need Help with Security Errors
    Buffer overflow tutorial: How to find vulnerabilities, prevent attacks
    SQL injection protection: A guide on how to prevent and stop attacks
    Experts rebuke programmers who use SQL injection as feature
    SANS: Application threats, website flaws pose biggest security threats
    Mozilla helps Adobe push out faster patches
    SSH key compromise shuts down Apache website
    IBM finds sharp spike in malicious content on trusted sites
    Application Attacks (Buffer Overflows, Cross-Site Scripting) Research

    RELATED GLOSSARY TERMS
    Terms from Whatis.com − the technology online dictionary
    anonymous Web surfing  (SearchSecurity.com)
    buffer overflow  (SearchSecurity.com)
    cache cramming  (SearchSecurity.com)
    cookie poisoning  (SearchSecurity.com)
    dictionary attack  (SearchSecurity.com)
    distributed denial-of-service attack  (SearchSecurity.com)
    JavaScript hijacking  (SearchSecurity.com)
    National Computer Security Center  (SearchSecurity.com)
    threat modeling  (SearchSecurity.com)
    trigraph  (SearchSecurity.com)

    RELATED RESOURCES
    2020software.com, trial software downloads for accounting software, ERP software, CRM software and business software systems
    Search Bitpipe.com for the latest white papers and business webcasts
    Whatis.com, the online computer dictionary



    Search and Browse the Expert Answer Center
    Search and browse more than 25,000 question and answer pairs from more than 250 TechTarget industry experts.
    Browse our Expert Advice



    Find Security Solutions for Your Business
    TechTarget Security Media
    Information Security View this month\\'s issue and subscribe today.
    Information Security Decisions Apply online for free conference admission.
    SearchSecurity.com
    HomeNewsMagazineMultimediaWhite PapersLearningAdviceTopicsEventsAbout Us

    About Us  |  Contact Us  |  For Advertisers  |  For Business Partners  |  Site Index  |  RSS
    TechTarget provides technology professionals with the information they need to perform their jobs - from developing strategy, to making cost-effective purchase decisions and managing their organizations' technology projects - with its network of technology-specific websites, events and online magazines.

    TechTarget Corporate Web Site  |  Media Kits  |  Site Map




    All Rights Reserved, Copyright 2003 - 2009, TechTarget | Read our Privacy Policy
      TechTarget - The IT Media ROI Experts