Archive for the ‘BinDiff’ Category

BinDiff 4.0 available today :-)


After several months of silence due to our team moving, finding a new home, and generally working really hard, we are happy to announce today that a new version of BinDiff is available! While the underlying comparison engine has only changed slightly, we have some significant improvements on the UI, and some improvements that are particularly useful for porting symbolic information from FOSS libraries into your disassemblies. In the following, I will highlight my favourite new features:

Call graph difference visualisation

With more complex differences between two executables, it is sometimes easy to miss the big picture by drilling down too much on changes to individual functions. With BinDiff 4.0, I now have the ability to not only examine changes on the level of the individual function, but also on the call graph. As with most UI improvements, an image is much more useful than a long diatribe; I will let the following screenshot speak for itself:

Examining changes on the callgraph level

Combined visualization of two flowgraphs

Ever since the very first version of BinDiff, the only way to examine a change in a flowgraph was by using our split-screen approach: One function on each side, laid out in a similar manner, with colors indicating changes. While this works pretty well (and is still my favorite way of looking at changes), it is sometimes a bit cumbersome. In the new UI, we added an additional way of examining changes: We merge the two graphs into one, and have a vertical split on the basic block / node level. This allows full-screen examination of changes without the need for splitting the screen.

The combined visualisation of changes

Iterative diffing

Over the last years, symbol porting has eclipsed patch analysis as my primary use for BinDiff. In many situations, I need to pull information from a FOSS project into an existing disassembly. I usually compile the FOSS project with symbols, attempting to approximate the build settings of the executable I am analyzing. I then BinDiff the disassembly against the compiled FOSS library and selectively import symbols and names for the functions that were recognized properly. While BinDiff often produces pretty good results, only a fraction of the functions will be recognized properly. In such situations, I often wished I could assist BinDiff infer further matches. With BinDiff 4.0, I can do just that: I can confirm that a pair of functions are matched correctly, and then tell BinDiff to re-run with the confirmed functions as starting points for further inference. This iterative approach allows me to match more and more functions while porting my symbols, yielding a much larger percentage of symbols in my disassembly than what would have been achieved in a single round of comparison.

Confirming a few matches

After confirming, click in the "Diff Database Incrementally" button

More Pie Charts

When comparing two pieces of related code, it is often useful to obtain a quick overview of the degree of code overlap between two files. What fraction of the functions in an executable could be mapped to the other executable? How similar were these functions? While all this information is available to BinDiff, up until the new version we never visualized this information in a central location. This has changed with the new UI – we now generate pretty pie charts, almost instantly usable in your favorite presentation software.

Pretty pies !

There are other new features in the UI – just give it a spin. After all, BinDiff is now directly available from our website and the price has been lowered to just 200 USD!

BinDiff 3.2.1… fun!


Hi there. I am one of the developers working on VxClass and the signature generation component in particular. However, working in a small company such as zynamics also means I get to do tons of other stuff, like preparing installer packages and other behind-the-scenes work.
So, in my first post I have the pleasure to announce a new version of our binary comparison tool: BinDiff 3.2.1. As the version number implies, this is mostly a bugfix only release, but with one important difference: As of now, all customers that place an order for BinDiff, automatically receive Debian GNU/Linux packages as well as the familiar Windows Installer package. Supported Debian-based distributions include:

  • Debian 5.0 (“Lenny”)
  • Ubuntu 10.04 LTS (“Lucid Lynx”)

Please note that for the Linux packages, we only support using BinDiff with Hex-Rays IDA Pro 6.0. For the Windows version we support the three latest versions of IDA Pro (5.6, 5.7 and 6.0, respectively).

This is how BinDiff looks on Linux:

BinDiff 3.2.1 in IDA 6.0 (Qt) on Linux

BinDiff 3.2.1 GUI on Linux

You can order BinDiff over the usual channels: e-mail, the order form on our web site or your favourite reseller.

This concludes my first post here, have fun diffing!

Recovering UML diagrams from binaries using RTTI – Inheritance as partially ordered sets


Wow, it’s been a while since we last blogged. Ok, time to kick off 2011 🙂

A lot of excellent stuff has been written about Microsoft’s RTTI format — from the ISS presentations a few years back to igorsk’s excellent OpenRCE articles. In the meantime, RTTI information has “spread” in real-world binaries as most projects are now built on compilers that default-enable RTTI information. This means that for vulnerability development, it is rare to not have RTTI information nowadays; most C++ applications come with full RTTI info.

So what does this mean for the reverse engineer ? Simply speaking, a lot — the above-mentioned articles already describe how a lot of information about the inheritance hierarchy can be parsed out of the binary structures generated by Visual C++ — and there are some pretty generic scripts to do so, too.

This blog article is about a slightly different question:

How can we recover full UML-style inheritance diagrams from executables by parsing the RTTI information ?

To answer the question, let’s review what the Visual C++ RTTI information provides us with:

  1. The ability to locate all vftables for classes in the executable
  2. The mangled names of all classes in the executable
  3. For each class, the list of classes that this class can be legitimately upcast to (e.g. the set of classes “above” this class in the inheritance diagram)
  4. The offsets of the vftables in the relevant classes

This is a good amount of information. Of specific interest is (3) — the list of classes that are “above” the class in question in the inheritance diagram. Coming from a mathy/CSy background, it becomes obvious quickly that (3) gives us a “partial order”: For two given classes A and B, either A ≤ B holds (e.g. A is inherits from B), or the two classes are incomparable (e.g. they are not part of the same inheritance hierarchy). This relationship is transitive (if A inherits from B, and B inherits from C, A also inherits from C) and antisymmetric (if A inherits from B and B inherits from A, A = B). This means that we are talking about a partially ordered set (POSet)

Now, why is this useful ? Aside from the amusing notion that “oh, hey, inheritance relationships are POSets“, it also provides us with a simple and clear path to generate readable and pretty diagrams: We simply calculate the inheritance relation from the binary and then create a Hasse Diagram from it — in essence by removing all transitive edges. The result of this is a pretty graph of all classes in an executable, their names, and their inheritance hierarchy. It’s almost like generating documentation from code 🙂

Anyhow, below are the results of the example run on AcroForm.API, the forms plugin to Acrobat Reader:

The full inheritance diagram of all classes in AcroForm


A more interactive (and fully zoomable) version of this diagram can also be viewed by clicking here.

For those of you that would like to generate their own diagrams, you will need the following tools:

Enjoy ! 🙂

BinDiff 3.2.0 released


We are pleased to announce the official BinDiff 3.2.0 release. zynamics BinDiff is the leading comparison tool for binary files, that assists vulnerability researchers and reverse engineers all over the world to quickly find differences and similarities in disassembled code. BinDiff uses a unique graph-theoretical approach to compare executables by identifying identical and similar functions, which is resilient even against changes in binaries introduced by different compilers and optimization settings.

With BinDiff one can conveniently identify and isolate fixes for vulnerabilities in vendor-supplied patches. One can also port symbols and comments between disassemblies of multiple versions of the same binary or gather evidence for code theft or patent infringement. BinDiff 3.2.0 compares binary files for x86, MIPS, ARM, PowerPC, and any other CPU architectures supported by IDA Pro. BinDiff displays function matches between two binaries in a clear way and easily ports function names, anterior and posterior comment lines, standard comments and local names from one disassembly to another.

So, what are the new features in zynamics BinDiff 3.2.0? In a nutshell, besides many bug fixes and a better IDA integration, the quality of the diff engine has been improved. Also, this version is shipped with a new C++ based exporter plug-in for IDA which unifies the export process between BinNavi and BinDiff. For more information, refer to the previous blog post titled “BinDiff 3.2 public beta phase starts today“, or take a look at the complete change list, which can be found in the manual.

BinDiff’s new colored “Matched Functions” view in IDA Pro v6.0  Beta 3.

The previous image shows the new “Matched Functions” view with a diff of two MyDoom binaries that were build by different compilers and with different optimization settings. Each match is colored from green to red according to the respective similarity in both binaries.

BinDiff’s “Matched Function” view in IDA Pro 64 6.0 Beta 3.

The image above shows the “Matched functions” view in IDA of a patch diff (MS-10-061 for Windows 7 x64). Changed functions can be easily spotted by sorting the table by similarity.

BinDiff's graph view of a single function diff.

BinDiff’s text view of a single function diff.

If you have any questions, please leave a comment or contact the zynamics support. If you are interested in a trial version, please write an email to More screenshots and an order form can be found here.

BinDiff 3.2 public beta phase starts today


Because this is my first post here I would like to introduce myself briefly. I have been working for zynamics since 2006 and my primary task is Java development. My main product responsibilities are the VxClass similarity graph visualization applet, parts of BinNavi and the complete BinDiff GUI.

Today we are officially starting the BinDiff 3.2 public beta phase. Besides many bug fixes the quality of the diff engine has been improved. Also, this version is shipped with a new C++ based exporter plugin for IDA which unifies the export process between BinNavi and BinDiff.

Here is an excerpt of the change list:

  • Added new matching algorithms (e.g. loop head matching)
  • Improved performance (better utilization of multi-core machines)
  • Support for multipe simultaneous differ instances
  • Memory optimizations
  • Function matches can be deleted and added manually
  • Colored matched function table rows (according to their similarity)
  • Various usability changes like wait dialogs for long running operations
  • ~80 more fixes and improvements in the exporter
  • ~50 more fixes and improvements in the BinDiff core engine
  • ~15 more fixes and improvements in the BinDiff GUI

We also increased our test database of IDB samples for stress testing the exporter and the BinDiff core engine to ~10GB. This includes large non-malicious samples (CISCO router images, Firefox, Acrobat, …), patch diff samples (Microsoft, MMO games, …), a huge selection of small but heavily obfuscated malware samples and some really obscure platforms. Every IDB we have ever received with a bug report or feature request is included in this database – please do keep ’em coming! In addition to that our distributed BinDiff engine integrated with zynamics VxClass, our malware clustering product, churns through gigabytes of fresh malware samples each month.

If you are a zynamics customer and interested in participating in the beta phase, please write an e-mail to Any kind of feedback, feature requests or bug reports are very much appreciated.

Las Vegas & the zynamics team


Along with RECon, the single most important date in the reverse engineering / security research community is the annual Blackhat/DefCon event in Las Vegas. Most of our industry is there in one form or the other, and aside from the conference talks, parties and award ceremonies, there’s also a good amount of technical discussions (in bars or elsewhere) that takes place.

This year, a good number of researchers/developers from the zynamics Team will be present in Las Vegas — alphabetically, the list is:

  1. Ero Carrera
  2. Thomas Dullien/Halvar Flake
  3. Vincenzo Iozzo
  4. Tim Kornau

So, if you wish meet any of the team to discuss reverse engineering, our technologies, our research, or the performance of the Spanish or German football team at the last world cup, do not hesitate to drop an email to — Vegas is always chaotic, and scheduling a meeting will minimize stress for everyone that is involved.

Specifically, the following topics are specifically worth meeting over:

  1. Chat with Ero over our unpacking engine (just presented at RECon) — and how it fits into the larger scheme of things (e.g. VxClass)
  2. Meet with Tim or Vincenzo to discuss automated gadget-finding for ROP, or anything involving the ARM/REIL translations
  3. Meet with Thomas/Halvar to discuss VxClass, automated malware clustering, automated generation of “smart” malware signatures etc.

Aside from this, if you are interested in …

  • … boosting your reverse engineering performance by porting symbols from FOSS software into your closed-source disassemblies (BinDiff)
  • … becoming faster at finding bugs by leveraging differential debugging, the REIL intermediate language and static analysis frameworks (BinNavi)
  • … enhancing team-based reverse engineering by pooling accumulated knowledge and sharing information (BinCrowd)
  • … automatically correlating and clustering malware and forensically obtained memory dumps, and automatically deriving detection mechanisms (VxClass)
  • … analyzing malicious PDF files including the embedded JavaScript code (PDF Dissector)

then do not hesitate to drop us mail — we’ll gladly show/explain what our tools/technologies can do.

See you there !

VxClass, automated signature generation, RSA 2010


Everybody is convening in San Francisco next week for RSA2010 it appears — the big annual cocktail & business card exchange event. If you are interested in any of our technology (automated malware classification, automated signature generation, BinDiff, BinNavi) and would like to meet up with me, please contact 🙂

Introducing: The official zynamics blog! :-)


Dear Readers (and fellow reverse engineers),

welcome to the shiny new zynamics blog!

Over the last several years, most of the zynamics crew has kept their own (personal) blogs, and frequently, topics that were of interest to the reverse engineer were scattered over several different blogs. It was not unusual to have to search through my blog, Ero’s blog, SP’s blog, or Vincenzo’s blog on the quest to finding a particular piece of information.

Also, at least one of those blogs was updated only sporadically (primarily … mine), and intermingled heavily with non-technical rants on the state of the world or the quality of the food in some random pub.

This situation was clearly untenable — and we therefore decided to pool all our reverse-engineering (and zynamics)-related stuff in one place.

On this blog, you will find posts regarding the following topics:

  • General reverse engineering
  • Bug hunting
  • Interesting uses of BinNavi / BinDiff
  • Automated malware classification / signature generation
  • Other things that I can’t think of yet, but that will certainly crop up in due time

So, enjoy the posts, and tell a friend!