technology from back to front

Big bucks for big bugs

I was recently working on a project where the client wanted us to add some features and updates to a web-facing database which they had paid some big name consultants to develop for them.

Wow, did what we received look impressive. It used some of the latest industry buzz-words: SQL Server, ASP.NET, Web services, to name a few; It came with pages and pages of documentation, with “wireframe models”, field-by-field breakdowns for each page, and even a schema diagram for the database. The documentation itself must have cost quite a bit (at a guess, it must have taken a Word-monkey at least 2 weeks to prepare).

However, when we started digging in, things didn’t look quite as impressive. Firstly, the documentation, detailed and copious as it was, was useless because it didn’t correspond to the actual code. Even the database schema didn’t match – it looked as if the documentation and the implementation had evolved independently.

As we started to take it apart and work out how it worked, more problems started to surface. Here’s a list of some of the more serious bugs we found.

  1. The schema for one of the tables was too wide; there were several very large VARCHAR columns (thousands of characters per column) in the definition of this table. The schema defined records which could be as big as 24000 bytes, whereas SQL Server has a limit of 8060 bytes. This means that inserts (and updates) of large records could fail or be truncated. The client never came up against this problem presumably because they hadn’t created a record big enough. How could the developers have just ignored the warning messages that SQL Server must have given?
  2. The website had a search page which sloppily used string concatenation to build the corresponding SQL query. Because no efforts were made to clean-up the user-provided input, this part of the website was vulnerable to SQL-injection attacks! In principle, a remote website visitor could type carefully crafted values into a search field and get the website to execute arbitrary SQL queries!

There were other weird parts in the code. For example, at one stage, the code concatenates several fields into a string using the pipe character (“|”) as a separator, and then later splits it again. Unfortunately, it didn’t make any effort to either check for/escape legitimate pipe characters in the field values, nor document that the pipe character shouldn’t be used in these fields. Why do this? VB.NET has perfectly usable record types (look for the Structure keyword – even QuickBASIC had the TYPE keyword since the late 80′s).

Working on this project has just given me more evidence to believe that the big name consultancies don’t give value for money.

by
francis
on
19/10/05
 
 


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