#Basic notepad antivirus code how to#
#Basic notepad antivirus code driver#
#Basic notepad antivirus code full#
#Basic notepad antivirus code registration#
#Basic notepad antivirus code code#

We can then detect when a process attempts to load a DLL, to load a driver, or to fire a new process. That callback allows us to be notified when the image is loaded into virtual memory, even itвЂ™s never executed. To be notified of loaded images, simply register PsSetLoadImageNotifyRoutine. An image is a PE file, either a EXE, a DLL or SYS file. The third dynamic threat is about images that can be loaded into memory. _In_ PCREATE_THREAD_NOTIFY_ROUTINE NotifyRoutine Thus, itвЂ™s able to look into the threadвЂ™s start address code, analyse it and either stop the thread or resume it. Each time a thread is created, the antivirus is notified with the TID and the PID. We can filter new threads with the PsSetCreateThreadNotifyRoutine callback. That way, a legit process can do malicious things.

#Basic notepad antivirus code code#

For example, one can inject some code into a legit process, and start a remote thread on that code inside the processвЂ™s context (easy to follow? рџ™‚ ). In the same idea than for processes, threads can be a way for malicious things to cause damages. } PS_CREATE_NOTIFY_INFO, *PPS_CREATE_NOTIFY_INFO _In_opt_ PPS_CREATE_NOTIFY_INFO CreateInfo _In_ PCREATE_PROCESS_NOTIFY_ROUTINE_EX NotifyRoutine, NTSTATUS PsSetCreateProcessNotifyRoutineEx(

#Basic notepad antivirus code driver#

It it founds something, the driver will simply set CreationStatus to FALSE and return. As the process is pending, the driver can tell its service to analyse the processвЂ™s memory for anything malicious. It receives the process name, the file object, the PID, and so. By doing this, on each process creation, and before the main thread starts to run (and cause malicious things) the antivirus callback is notified and receives all the necessary information. Antivirus should register a PsSetCreateProcessNotifyRoutineEx callback. The first thing to protect the user from, is the launching of malicious processes. To learn about hooks, you can check that basic example: To learn about coding drivers, you can check that useful links:

#Basic notepad antivirus code how to#

NOTE: I will not cover the workarounds with hooks for pre-Vista systems, because itвЂ™s easy to find on the internet, and because it would need a whole chapter to explain how to hook, where to hook and soвЂ¦ But you have to know itвЂ™s the same idea than the kernel APIs, except that you have to implement yourself what Microsoft provided on Vista+ systems. This was not the case for hooks, as the implementation was totally product dependant.

#Basic notepad antivirus code registration#

More, that kind registration based system allows us to dispatch our system security into layers, where several products with different aims can cohabit. That way, itвЂ™s easy to register an antivirus product into the kernel.

On Vista+, Microsoft provided APIs to insert our low level driver between userland calls and kernel APIs.

They used what we call вЂњHooksвЂќ (API detours for filtering purpose).

However, on Pre-Vista systems, Antivirus companies used to use rootkit-like features to guard the doors (even if it was not recommended at all by Microsoft) and be able to protect your system.

DonвЂ™t be stunned if building an antivirus for pre-Vista systems can be a real pain, because it was not designed for this. Starting with Vista, Microsoft understood that the Antivirus industry needed keys to enter the kernel and activate filters in strategic places, such as file system, registry and network. One can found here the pointers to design an antivirus engine, or simply learn how most of them are built.ДЇor a good protection, an Antivirus must have at least one driver, to be able to run code in kernel and overall have access to kernel APIs. So, IвЂ™ll cover here the guidelines for a basic antivirus coding, for Windows and in C/C++.

#Basic notepad antivirus code full#

IвЂ™m not telling kiddies are not skilled, but IвЂ™m telling building an antivirus engine needs either lot of skilled people with full time job plus lot of time to release a decent software or lot of money to pay them рџ™‚ (in case they are not volunteer). IвЂ™ve also seen many вЂњAntivirus softwaresвЂќ made by kiddies, with very few still-at-school people and about 4 hours per day of coding on several weeks. When roaming around the techies forums, I often see some people (and many not very experienced) asking for вЂњHow do I make an antivirusвЂќ, sometimes with not very adapted languages (bat, PHP, вЂ¦) and having a wrong idea of what an antivirus is, and how it should be built. User Rating 4.57 ( 14 votes) Introduction