[Owasp-leaders] Business Logic Cheatsheet

Eric Sheridan eric.sheridan at owasp.org
Thu Oct 24 15:37:43 UTC 2013


I agree with Jeff in principle on this one. The term "business logic
flaw" is often used to encompass, dare I say this, anything an automated
tool cannot find. When, more correctly, it focuses on those issues with
strong business context that do not tie directly to a commonly excepted
vulnerability class/CVE/etc... unless the referenced taxonomy consists
of insanely broad definitions ;)

-Eric

On 10/24/13 10:46 AM, Jim Manico wrote:
> Let me try that again, Jeff. I do not agree that 90% of the cheatsheet
> should be removed, but adding your suggestions below is useful. I'll
> send an updated CS to the list when done.
> 
> Regards,
> --
> Jim Manico
> @Manicode
> (808) 652-3805
> 
> On Oct 24, 2013, at 9:38 AM, Jeff Williams <jeff.williams at owasp.org
> <mailto:jeff.williams at owasp.org>> wrote:
> 
>> Hi,
>>
>> I think this is a worthy and important effort, and I appreciate the
>> work so far, but this draft mostly focuses on problems that are better
>> suited to remain in other categories. I apologize for the severe
>> comment, but I would delete 90% of what is in this cheatsheet and
>> focus on the core problem and solutions.
>>
>> To me, it's only a business logic problem if you have to know the
>> business rules in order to identify it.  A business rule is like "only
>> IRA holders over age 55 can trade index funds."  Notice that it's not
>> about any security mechanism.  Instead, business logic vulnerabilities
>> represent a mismatch between business expectations and the
>> application's code.  You can't find a business logic problem without
>> first talking to the business about their rules and understanding
>> their business.  Almost nothing in the article really talks about this
>> kind of problem.
>>
>>
>> I think it might help to quote the "Business Logic Vulnerability" page
>> from OWASP (2008) --
>>
>>         Most security problems are weaknesses in an application that
>>         result from a broken or missing security control
>>         (authentication, access control, input validation, etc...). By
>>         contrast, business logic vulnerabilities are ways of using the
>>         legitimate processing flow of an application in a way that
>>         results in a negative consequence to the organization. For
>>         example:
>>
>>           + Purchase orders are not processed before midnight
>>           + Written authorization is not on file before web access is
>>             granted
>>           + Transactions in excess of $2000 are not reviewed by a person
>>
>>         Many articles that describe business logic problems simply
>>         take an existing and well understood web application security
>>         problem and discuss the business consequence of the
>>         vulnerability. True business logic problems are actually
>>         different from the typical security vulnerability. Here are
>>         some examples of problems that are not business logic
>>         vulnerabilities:
>>
>>           + Performing a denial of service by locking an auction
>>             user's account
>>           + Posting unvalidated input publically
>>           + Cracking MD5 hashes
>>           + Brute forcing a password recovery scheme
>>
>>         Too often, the business logic category is used for
>>         vulnerabilities that can't be scanned for automatically. This
>>         makes it very difficult to apply any kind of categorization
>>         scheme. Business logic problems are different from
>>         authentication problems and every other category. There are
>>         many signficant business logic vulnerabilities, but they are
>>         far less common than the type of items in the OWASP Top Ten
>>         for example.
>>
>>         A nice rule-of-thumb to use is that if you need to truly
>>         understand the business to understand the vulnerability, you
>>         might have a business-logic problem on your hands. If you
>>         don't understand the business, you can't see business logic flaws.
>>
>>
>> Again, I apologize for the harsh comment.  I think this is important
>> and we should get it as good as we can.
>>
>> --Jeff
>>
>>
>> On Wed, Oct 23, 2013 at 1:20 PM, Jim Manico <jim.manico at owasp.org
>> <mailto:jim.manico at owasp.org>> wrote:
>>
>>     Hello folks,
>>
>>     We just released a new cheatsheet, the business logic cheatsheet
>>     for developers. Kudos to Ashish Rao and David Fern for working on
>>     this together.
>>
>>     https://www.owasp.org/index.php/Business_Logic_Security_Cheat_Sheet
>>
>>     Feedback is always appreciated.
>>
>>     Aloha,
>>     Jim Manico
>>     OWASP Board Member
>>     _______________________________________________
>>     OWASP-Leaders mailing list
>>     OWASP-Leaders at lists.owasp.org <mailto:OWASP-Leaders at lists.owasp.org>
>>     https://lists.owasp.org/mailman/listinfo/owasp-leaders
>>
>>
> 
> 
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