RE: Techniques for Vulneability discovery

["W. Lee Schexnaider" <lschex () schex-family com>]

Hello,

As a software tester I might offer some information.

I am primarily a "black box" tester, which means I do not go into the code.  I use the product as a user would.  We do 
some automated testing with tools like Winrunner.

However, many testers do exploratory or ad hoc testing for these items.  This involves using the program thinking of 
ways to break it, theny trying them and documenting the results.  In many cases there are requirements to test against, 
but these rarely find the type of problems you are addressing.  However, requirements and written test cases can ensure 
that the bug does not reappear due to code reuse or old code getting into a build.

Testing can be a basic as holding down a key in a field for two minutes to see if a buffer overflow happened (it did). 
I include things like the entry of bad data and other items in my test cases. 

> From a customer standpoint, many people do not allow new code to be placed on production systems.  They have separate 
> test systems where the program is exercised before it can go on  to production system.  Such a system can lend itself 
> to automating test cases for new version of existing software.

It really comes down to having people who like to break software.  These do not have to be programmers or IT admins.  
My background is in newspaper journalism. In some cases specific technical knowledge may be needed.  But often the 
technical person needs to be teamed with someone who thinks more like a user.

If a programmer says "someone would never do that" in reference to an action with a program, you can bet everything you 
own that at some time somebody will.  Take the classic case of a video card that if it had more than one monitor 
connected to it, the monitors would catch fire!

  

-----Original Message-----
From: kaipower [mailto:kaipower () subdimension com]
Sent: Thursday, April 04, 2002 7:05 PM
To: security-basics () securityfocus com; vuln-dev () security-focus com;
vuln-dev () securityfocus com
Subject: Techniques for Vulneability discovery


Hi,

After reading the mailing list for quite a while, there is a burning
question which I kept asking myself:

How do experts discover vulnerabilities in a system/software?

Some categories of vulnerabilities that I am aware of:
1) Buffer overflow (Stack or Heap)
2) Mal access control and Trust management
3) Cross site scripting
4) Unexpected input - e.g. SQL injection?
5) Race conditions
6) password authentication

Do people just run scripts to brute force to find vulnerabilities? (as in
the case of Buffer overflows)
Or do they do a reverse engineer of the software?

How relevant is reverse engineering in this context?

Anybody out there care to give a methodology/strategy in finding
vulnerabilities?

Mike



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