Secure Coding mailing list archives

Static Vs. Binary


From: jsteven at cigital.com (John Steven)
Date: Thu, 30 Jul 2009 17:20:52 -0400

Something occurred to me last night as I pondered where this discussion?s
tendrils are taking us.

An point I only made implicitly is this: The question<for years<has been
?conduct your SA on source code or binary??. You can see that there are
interesting subtleties in even those languages that target intermediate
representational formats (like Java and the .NET family of languages that
compiles to MSIL). The garbage-collection-optimization problems that plague
those asking ?How do I assure password String cleanup in Java? are of the
same ilk as the gcc optimizations that trouble the C/C++ realm.

Yes, this question is still pertinent. It _is_ interesting to those looking
for thorough/sound analysis to consider fidelity and resolution at this
level. People are beginning to echo what I've been saying for years, "this
problem extends beyond the initial compile into the runtime optimizations
and runtime compilers". My previous post reiterates that there's a lot more
to it than most people consider.

I think I allowed that clarification to muddle my more strategic point:

   -----------------
    Whereas THE question used to be source code vs. binary representation,
    the question is NOW: "What set of IOC-container/XML combos,
    aspect weaver results, method/class-level annotations, and other such
    tomfoolery governs the execution of my application beyond what the
    compiler initially output?
   -----------------

As Fortify, Veracode, and others punch out this 'static analysis on binaries
via SAAS' battle, they and the organizations they serve would do well to
keep this question in mind... Or risk the same failures that the current
crop of parser-based static-analysis tools face against dynamic approaches.

-jOHN

On 7/29/09 8:44 AM, "John Steven" <jsteven at cigital.com> wrote:

All,

The question of ?Is my answer going to be high-enough resolution to support
manual review?? or ?...to support a developer fixing the problem?? comes down
to ?it depends?.  And, as we all know, I simply can?t resist an ?it depends?
kind of subtlety.

Yes, Jim, if you?re doing a pure JavaSE application, and you don?t care about
non-standards compilers (jikes, gcj, etc.), then the source and the binary are
largely equivalent (at least in terms of resolution).... Larry mentioned gcj.
Ease of parsing, however, is a different story (for instance, actual
dependencies are way easier to pull out of a binary than the source code,
whereas stack-local variable names are easiest in source).

Where you care about ?a whole web application? rather than a pure-Java module,
you have to concern yourself with JSP and all the other MVC technologies.
Placing aside the topic of XML-based configuration files, you?ll want to know
what (container) your JSPs were compiled to target. In this case, source code
is different than binary. Similar factors sneak themselves in across the Java
platform. 

Then you?ve got the world of Aspect Oriented programming. Spring and a broader
class of packages that use AspectJ to weave code into your application will
dramatically change the face of your binary. To get the same resolution out of
your source code, you must in essence Oapply? those point cuts yourself...
Getting binary-quality resolution from source code  therefore means predicting
what transforms will occur at what point-cut locations. I doubt highly any
source-based approach will get this thoroughly correct.

Finally, from the perspective of dynamic analysis, one must consider the
post-compiler transforms that occur. Java involves both JIT and Hotspot (using
two hotspot compilers: client and server, each of which conducting different
transforms), which neither binary nor source-code-based static analysis are
likely to correctly predict or account for. The binary image that runs is
simply not that which is fed to classloader.defineClass[] as a bytestream.

...and  (actually) finally, one of my favorite code-review techniques is to
ask for both a .war/ear/jar file AND the source code. This almost invariable
get?s a double-take, but it?s worth the trouble. How many times do you think a
web.xml match between the two? What exposure might you report if they were
identical? ... What might you test for If they?re dramatically different?

Ah... Good times,
---- 
John Steven 
Senior Director; Advanced Technology Consulting
Direct: (703) 404-5726 Cell: (703) 727-4034
Key fingerprint = 4772 F7F3 1019 4668 62AD  94B0 AE7F EEF4 62D5 F908

Blog: http://www.cigital.com/justiceleague
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http://www.cigital.com
Software Confidence. Achieved.


On 7/28/09 4:36 PM, "ljknews" <ljknews at mac.com> wrote:

At 8:39 AM -1000 7/28/09, Jim Manico wrote:

A quick note, in the Java world (obfuscation aside), the source and
"binary" is really the same thing. The fact that Fortify analizes
source and Veracode analizes class files is a fairly minor detail.

It seems to me that would only be true for those using a
Java bytecode engine, not those using a Java compiler that
creates machine code.




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