The application logic itself must be careful constructed and must include security mechanisms. Input should never be assumed to be what was expected. It must be tested, validated, and filtered. Applications that call up files, especially directly from the file system, must be carefully checked. Its too easy to expose source code, or worse yet, system files. Anything that even resembles javascript or vbscript must be removed. Inadvertently storing scripts entered by a hacker will allow them to be replayed against customers, resulting in the web site attacking customers or divulging session information to the hacker. All error messages must be handled. Unhandled (raw) error messages are a roadmap through the application and database. Database calls must be structured carefully, and any user input that will used in the query must be scrutinised. Carefully constructed input could allow a hacker to piggy-back legitimate queries with their own, giving them access to the database through the web application.

Security throughout

The management of web application vulnerabilities must occur in several different areas.

Security must be brought to the web development team. Create and enforce secure coding practices. Assess the code while its being developed, to identify insecure techniques before they are replicated. Ensure that QA test for security as well as functionality. Think security during change control procedures - don't consider just the functional and performance impact of changes, consider the security impact as well.

The security department must learn application security. Create and promote internal awareness campaigns. Work with the development team to develop and publish best practices, and enforce those best practices. Create procedures to work with development to remediate vulnerabilities. Audit production systems frequently and with each change. Baseline and trend the results to gain a historical perspective of application security. Implement web application security assessments into Certification and Assessment programmes. Most importantly, assess applications in depth. Ensure the security is 'baked-in', not 'brushed-on'.


Automated assessment tools can help introduce and maintain security throughout the application life cycle. Best of breed tools include: WebInspect from SPI Dynamics, AppScan from Sanctum and ScanDo from KaVaDo.



First Base Technologies are exhibiting at Infosecurity Europe 2004 which is Europe's number one IT Security Exhibition. The event brings together professionals interested in IT Security from around the globe with suppliers of security hardware, software and consultancy services. Now in its 9th year, the show features Europe's most comprehensive FREE education programme, and over 200 exhibitors at the Grand Hall at Olympia from 27th to the 29th April 2004. www.infosec.co.uk.