A small, on the fly video presentation of my new utility.
The emphasis of this application stands on parsing correctly the PDF format, if it can’t because the PDF is malformed (very common among malicious PDFs), then it provides the tools to read the objects nonetheless. I tested it on many PDF (also malicious ones) and it handles all of them very well.
As I have written this application in five days, there are still some small features I’d like to add, but most of the code is already there. I started the development of it quite some time ago on a weekend while I was sick at home and have found only now the time to finish it.
I have no plans about how and when to release it yet, but some friends of mine will start using it in real world scenarios.
P.S. Thanks to Alessandro Gario for the throughout testing.
This week, after months of development of bigger projects, I found some time to windbg “ntoskrnl.exe” and write a utility. It is called Filter Monitor and shows some key filters installed by kernel mode components.
“As you probably all know the Service Descriptor Table has been a playground on x86 for all sorts of things: rootkits, anti-viruses, system monitors etc. On x64 modifying the Service Descriptor Table is no longer possible, at least not without subverting the Patch Guard technology.
Thus, programs have now to rely on the filtering/notification technologies provided by Microsoft. And that’s why I wrote this little utility which monitors some key filters.
Since I haven’t signed the driver of my utility, you have to press F8 at boot time and then select the “Disable Driver Signature Enforcement” option. If you have a multiple boot screen like myself, then you can take your time. Otherwise you have to press F8 frenetically to not miss right moment.
A disclaimer: the boot process can be a bit annoying, but the utility should be used on virtualized systems anyway, as I haven’t fully tested it yet. I doubt that it will crash your system, I guess the worst scenario is that it won’t list some filters. It should work on any Windows system starting from Vista RTM and I have provided an x86 version and an x64 version. But the truth is that I have tested only the x64 version on Windows 7 RTM. Last but not least, I can’t guarantee that this utility will work on future versions of Windows, it relies heavily on system internals.
Now, let’s run it. The supported filters/notifications at the time are these: Registry, Create Process, Create Thread and Load Image. “Registry” stands for CmRegisterCallback filters. “Create Process” for PsSetCreateProcessNotifyRoutine callbacks. “Create Thread” for PsSetCreateThreadNotifyRoutine callbacks. And “Load Image” for PsSetLoadImageNotifyRoutine callbacks.
The “Additional Info” in the list view provides internal information like the address of the callback function.
There are some default filters registered by system components, but, as you can notice, there are also Kaspersky components. That’s because some filters (like the registry filter) are not used by system components and I needed a tool which would make use of these filters for my little demonstration.
The version of Kaspersky I have installed is the latest one available on the internet which is: 9.0.0.463.
I created for this demonstration a little executable called “k-test” (what you see on the desktop are three copies of the same executable) which copies itself in a directory called “borda” in the “Roaming” directory of the operating system. It then creates a value in the Run key of the registry to execute itself at each start-up. Finally, it launches itself from the “Roaming” directory and ends.
This is a typical malware behavior. Beware that the signature of the application itself is not contained in the databases of Kaspersky as I have written it on the fly, but it detects the suspicious behavior, stops execution and deletes the file. And it does this every time I launch the test application.
Now let’s get to the part where I show an additional functionality of the Filter Monitor which is the ability to remove registered filters and see what happens if I remove the filters installed by klif.sys, which is the “Kaspersky Lab Interceptor and Filter” driver. As the name suggests, this driver intercepts and filters: it installs all four of typologies of filters listed by the Filter Monitor. On x86 instead of calling CmRegisterCallback it additionally hooks about 60 functions of the Service Descriptor Table (which is a lot), but that’s no longer possible on x64.
So, let’s remove the filters and re-launch k-test. It works now.
Final disclaimer: It is not my intent to comment on security features of anti-viruses, I just wanted to present my new tool and show its functionalities. I was already familiar with the internals of Kaspersky before writing this utility.
I hope you enjoyed the presentation.”
P.S. A huge thanks goes to Alessandro Gario for providing me with all the different versions of ntoskrnl.exe.
Here’s a presentation of my new tool. I called it Native Blocks. It’s a re-assembler basically. Since a written presentation would take me too much time I prepared a video presentation.
Again, this is a pre-alpha. This tool will soon support other technologies such as java, actionscript and maybe even x86. Right now it only supports .NET (and even .NET support will be hugely improved, like for instance supporting the direct modification of assemblies without having to use Rebel.NET).
The development of this tool depends mainly on the interest of people.
As I can be considered a student from now on, I would like to earn some extra money by writing tools such as this one. I have still my job as consultant, but it’s a very limited partime, because I just became a student.
This tool is in my opinion pretty good, it is not only good for deobfuscation purposes but also patching and assembling on the fly.
If this tool can be sold, then the support of technologies will depend on requests. I think I’ll add Java immediately and after that maybe x86/x64. Again it depends.
Half of the text of this article comes from my larger paper “Dynamic C++ Proposal”. I decided that it was useful to take the part about Qt internals, put it into another article and extend it by adding a reversing part. Because of its nature, this is not the usual kind of article I write. In fact, I wrote the reversing part in less than a day. So, this is a very easy one. However, I think it is useful for people who need to reverse a Qt application and certainly wouldn’t consider reading my other paper about Dynamic C++, which doesn’t sound like a paper about Qt and, in fact, isn’t a paper about Qt: the paragraph about Qt is only one among many others. Moreover, I haven’t seen serious articles about this subject.
The first thing which needs to be considered when reversing Qt applications is what Qt brought to the C++ language. Events (inside the Qt framework) are just virtual functions, so nothing new there. This is not a C++ reversing guide. What is new in Qt are signals and slots, which rely on the dynamism of the Qt framework.
So, first thing I’m going to show how this dynamism works. The second part focus on reversing and, at that point, I will show how to obtain all the metadata one needs when disassembling a “Q_OBJECT” class.
Today I’m releasing the Rebel.NET software and its official guide.
Rebel.NET is a rebuilding tool for .NET assemblies which is capable of adding and replacing methods and streams. It’s possible to replace only a limited number of methods or every method contained in a .NET assembly. The simplicity of Rebel.NET consists in the replacing process: one can choose what to replace. Rebel.NET is, mainly, a very solid base to overcome every .NET protection and to re-create a fully decompilable .NET assembly. As such, Rebel.NET has to be considered a research project, not an encouragement to violate licensing terms.
As I have written the software and the article in this week when during my sickness (fever), I’m expecting bugs and typos. Please report them.
Of course, I’ve tested the Rebel.NET with more advanced .NET assemblies than those presented in the guide.
DynLogger logs all dynamically retrieved functions by reporting the module name and the requested function. It can come very handy when one wants to know a “hidden” function used by an application.
I recycled the code of a bigger project to write this little application. It’s a very small utility, but it might be of use after all. It was tested on XP and Vista, both x86 and x64. It works for .NET application as well. Just start the logging process, the log will be saved after you quit the monitored application.
In the last days I’ve been quite sick, so I decided that as long as I had to stay in bed I might at least use the time to do something useful (or quite so). What happened is that someone asked what the Rich Signature was. It might seems strange but in all these years I didn’t even notice it, I just overlooked it as part of the dos stub (incredible but true). Unable to answer, I noticed together with this person that the subject was completely undocumented. It might not even be much important, but you might find it an interesting reading after all. http://ntcore.com/Files/richsign.htm
Since information about this topic is non-existent, the reader might not know what I’m talking about:
