polymorphic virus code
In this case, we are referring to unique, dynamically-generated code (i.e. Each time a file infected with polymorphic virus is executed; it not just replicates itself, but changes the codes. Listing 5.Using FPU instructions to calculate a delta offset address. Home > Education > Polymorphic Code. This way, traditional security solutions may not easily catch them because they do not use a static, unchanging code. The word polymorphism is used in different settings and portrays circumstances in which something happens in a few unique structures. Once we know the memory address of this instruction, we can work out the address of anything else in our function. This is due to processor cache effects. The prologue of the decryption function is simply the first section of the function, which contains some standard elements like setting up the stack frame and preserving registers. Since the public and private keys are mathematically related, it is theoretically possible to “crack” a public key and obtain the private key, however there are no known practical ways of doing this. Share this on your social networks. • The idea is to encrypt the code with a random key and decrypt it at runtime. Delta offset calculations can rouse the suspicions of antivirus programs, since normal applications do not have a need for this kind of thing. I have included two different decryption functions below, both generated by our engine from the same input data. Simple polymorphic virus written in Python for the "Malware analysis and Design" Master course in University of Verona That means it can produce a million or so variants rather than a billion. The code of the polymorphic engine takes about half of the actual virus code, and there are random byte-based blocks inserted between the generated code chains of the decryptor. Listing 15.Definition of the polymorphic engine class. Now that the entire code of the function has been generated, we can write out the encrypted data block, so it will follow the code of the function. The function will return the size of the decrypted data. Encryption is the most common method to hide code. The initial exploit of a system often comes from human error, performing an action like downloading and running an infected email attachment, or visiting a website that has been compromised. The advantage of these algorithms is that they are heavily studied and their strengths and weaknesses are known. computer instructions). Like call, this allows us to obtain the location of an instruction in our function and we can use a similar delta offset calculation to refer to data stored after the function. • Polymorphic viruses randomly encode or encrypt the program code in a semantics-preserving way. CyberHoot comes with built in cybersecurity assessments to help our clients do just this. If it has not reached 0, the loop is repeated. Just like regular encrypted viruses, a polymorphic virus infects files with an encrypted copy of itself, which is decoded by a decryption module. For small blocks of data, this does not create a noticeable difference, but for large buffers the performance reduction can be significant and should be taken into account. A virus replicates by itself and modifies the other programs by inserting its code. Music video code . Listing 14.Place the encrypted data block after the end of the decryption function. Listing 17.Testing the polymorphic engine. A polymorphic virus uses a variable encryption key to change each copy of the virus. In order to prevent this, we must generate extra code between these two instructions, and utilize a different means of getting values from the stack. Our dynamically generated code can be located anywhere in memory and launched from there (assuming the memory region has the appropriate executable flags set). Sign up with CyberHoot today and sleep better knowing your. This article explains all the steps needed to write a C++ program which dynamically generates encryption algorithms in x86 assembly code. References in periodicals archive ? Virus is one type of malware. In our case we'll stick with 32-bit code. i want a virus to affect entire LAN computers, please give me code to pass virus to one computer another and attack all computer same time. This approach to the delta offset calculation is sometimes used in exploits, e.g. Note: Les dommages causés par ces virus sont irréversibles # 1 Désactiver Internet de manière permanente. A metamorphic virus is capable of rewriting its own code while maintaining its … Polymorphic malware also makes changes to code to avoid detection. Listing 9.Generating the code of the decryption loop. In time, polymorphic algorithms evolved and became ever more sophisticated, in order to make it as difficult as possible for antivirus programs to analyze viruses and run them in an emulated environment. Among other things, this contains the memory location of the most recently executed FPU instruction. The polymorphic engine of the virus implements a build-and-execute code evolution. In our case the one parameter will be a pointer to the buffer where we will store the decrypted data. We will employ the delta offset technique for this purpose. malware malware-research information-security malware-samples malware-development linux-malware malware-sample parasite shellcode-injection elf-virus code-injector infector elf-infector infect-binaries segment-padding … The epilogue, in other words, the last portion of the function, is where the original value of the EBP register is restored, and if necessary, the sensitive registers ESI EDI EBX, whose state must be preserved across function calls according to the stdcall convention. signature-based identification programs. PPE-II – Prizzy Polymorphic Engine (by Prizzy) – a polymorphic engine which exploits MMX and FPU code, as well as intentional brute-force calculations in its code, so as to slow down operation of emulation strategies used by antivirus software; In most cases, this type of encryption was used in executable file infectors. Using the pseudoinstructions we generated earlier and which we used to encrypt the data, we will now generate instructions which perform the encryption process in reverse, and place them in a loop that repeats this process on each input block. For example, 1+3 and 6-2 both achieve the same result while using different values and operations. The loop takes successive encrypted blocks of data from the buffer at the end of the function, then carries out all the decryption instructions on each block, and writes the result to the output buffer. Home Information technology Computer program Malware Computer virus Polymorphic code. Cybersecurity policies are a great way to keep staff informed and accountable to company expectations on behaviors and technology usage. Polymorphic Virus Definition. Add your article. Alignment between functions is normally achieved with the 1-byte instruction nop (no-operation) or int3 (an interrupt for the purpose of trapping into a debugger). A Polymorphic Virus is a type of ‘shape-shifting’ virus, producing malicious code that is able to replicate itself with new signatures but identical payloads over and over again. This makes it possible for the function to output extra values. – Each copy of the code is different because of the use of a random key. All the above algorithms are extensively documented, and implementations can easily be found for many programming languages. Pseudoinstructions will be randomly generated for the encryption process, and they will later be used to generate the decryption code. For instance, our encrypted data is accessed in 32-bit blocks (since we are using 32-bit registers), which means memory addresses should be divisible by 4. Our decryption function will use the standard 32-bit processor registers, and will obtain its one parameter from the stack using the stack frame pointer in the EBP register. Listing 16.The main function, which performs the encryption and generates the polymorphic code. Help Friends, Family, and Colleagues become more aware and secure. Listing 10.Setting up the return value of the decryption function (the size of the decrypted data) as well as any other final values we wish to place in registers. In software engineering, it depicts the idea that various kinds can be gotten through a similar interface. detect various sequences of computer code known to be used by a given mutation engine to decrypt a virus body. In order to change its physical file composition during each infection, the polymorphic virus encrypts its code and adopts a different encryption key each time. The RSA company even organized a public challenge to break RSA keys, where the largest prize was $US200,000 for cracking a 2048-bit key. Related Terms: Macro Virus, Memory-Resident Virus, Melissa Virus. use of a random key. However, polymorphic engines have found another use: software protection systems, or exe-protectors, such as PELock, ASProtect, EnigmaProtector, Themida, and Obsidium. Quelques autres codes source de virus. You may have heard of the term "polymorphic virus". The data can be smaller than this (it will be rounded up to a multiple of 4). It depends on the use of the call assembly instruction, normally used to call a function. Otherwise, the operating system's protection mechanisms, like e.g. These viruses repeatedly change their overt characteristics in an attempt to evade and outwit your computer’s defenses and sabotage your system. In this way, it is possible to discover tracing of our code by debuggers including OllyDbg. We will need to determine its address at runtime, through the use of relative addressing. A Polymorphic Virus is a type of ‘shape-shifting’ virus, producing malicious code that is able to replicate itself with new signatures but identical payloads over and over again. Voici quelques autres codes sources pour créer un virus de bloc-notes sur un ordinateur Windows. With encrypt In the case of polymorphic viruses, however, this decryption module is also modified on each infection. My grades was in a mess, i was not proud of myself, but something needed to be done you know what i mean. Instructions which access memory are faster if the data they read or write is aligned, i.e. Polymorphic is a subtype of File Infector Virus, infecting files and folders. The build routine of the virus is already metamorphic. This threat continues to grow. This technique has its roots in computer viruses. There is a wide variety of encryption algorithms available. I have included the class header below, followed by the implementation of the main function which generates the polymorphic code. Listing 12.Aligning the size of the decryption function to the specified granularity. (You can also recognize an infected file by the string "-----this is silly python virus-----" which is printed whenever the infected program is executed.) Listing 19.Decryption function in another variant. Written Information Security Policy (WISP). What is a polymorphic virus? Now that you have seen the successive elements of the operation of our polymorphic engine, it's time to bring it all together. Here are the steps any company should take to avoid falling victim to Polymorphic Viruses. Another reason for the attraction is that polymorphic code is harder for researchers to pick apart and track down its shifting series of operations. employees are cyber trained and on guard! The virus rebuilds itself on the stack with push instructions. To vary their physical file makeup during each infection, polymorphic viruses encrypt their codes and use different encryption keys every time. This polymorphic botnet contained at least 12,000 compromised computers and was able to change itself up to 19 times a day to avoid detection. One virus author even created a tool kit called the “Dark Avenger’s Mutation Engine” (also known as MTE or DAME) for other virus writers to use. Cependant, ces virus sont dangereux et peuvent détruire votre ordinateur. Listing 1.Pseudocode in C++ for the decryption function that we will generate. To enable polymorphic code, the virus has to have a polymorphic engine (also called mutating [...] engine or mutation engine) [...] somewhere in its encrypted body. We could add additional features, such as: This can all be taken quite a long way, especially making use of a library like AsmJit, which greatly simplifies the dynamic generation of assembly code, including the use of all current extensions of x86 and x64 processors. This is the stark reality of the threat the polymorphic virus poses to your computer systems and personal data. Unlike symmetric encryption algorithms, where a leaked key means anyone can read the message, asymmetric encryption algorithms ensure that only the holder of the private key can decrypt the message. The combination of call and pop r32 can cause the application to be suspected of containing malware. Soon, virus creators developed decryption algorithms whose code was uniquely generated every time, which allowed viruses to be created which could not be detected using static signatures. The 1260 virus made its replication code simpler by only allowing up to 5 junk instructions in any one location, and by generating only a few hundred of the possible x86 junk instructions. Listing 8.Generating initialization code for the regKey register. The registers used for decryption, for holding a pointer to the encrypted data, and for holding a pointer to the output buffer, will be selected randomly each time the decryption routine is generated. This factoring process currently takes an enormous time. But fast-changing polymorphic malware now makes up an overwhelmingly large percentage of the malware organizations are facing. It has the potential to contaminate your data by writing certain malicious codes. Our decryption function will return a value of type DWORD (a 32-bit value corresponding to unsigned int), which indicates the size of the decrypted data. Due to the level of complexity of polymorphic engines, and the necessity of an in-depth understanding of assembly language for their creation, these days polymorphic engines are rarely used (one exception to this is Virut which, I'd like to point out, is strongly suspected of being Polish in origin!). The polymorphic virus is not immune to security. Having generated the entire code of the decryption function, we can now correct any relative addresses used earlier, which in our case is just the address of the encrypted data. One of the simplest and best ways to protect your systems from dynamic, changing code is to ensure you have the right type of security solution software in place. Listing 2.Random selection of registers for the decryption function. This is the main goal of a polymorphic engine, after all! They are used to make it more difficult for an application's code to be analyzed by crackers (i.e. We take advantage of the fact that this instruction stores a return address on the stack before jumping to a chosen memory address. Non-aligned addresses will be read from the slower L2 cache or directly from the computer's RAM. That is, the code changes itself each time it runs, but the function of the code will not change at all. Sound simple? Polymorphic Code is the debut studio album by French one - man band The Algorithm, signed by Basick Records and released on November 19, 2012. It's important to remember that the memory where the code is found should be allocated with the correct executable flags. In computing, polymorphic code is code that uses a polymorphic engine to mutate while keeping the original algorithm intact. Heuristic based solutions examine the actions and activities taken by code running on your system and prevent certain things from happening: for example, encrypting files should never happen and many heuristic programs prevent that helping you avoid a ransomware attack. At the start of the decryption function we will load the encrypted key into regKey, and then decrypt it. Your own good judgment is often your first and best line of defense. Imagine a threat that can adapt to every form of defense you throw at it, a threat that constantly changes to avoid detection, a threat that is relentless. In our case, we work out the location of our "encrypted" data by adding the number of bytes between the delta_offset: label and the end of the function. Have a high-quality heuristic and signature based antivirus solution will give far more comprehensive protection than just signature based or just heuristic based antivirus protection. At the moment, we don't know the size of the remainder of the decryption function, which is why we will need to update this value later, once we have generated all the other instructions of the decryption function. The first known polymorphic virus was called 1260, or V2PX, and it was created in 1990 as part of a research project. people who try to break software protection), and to make it harder for automated unpackers to be created (i.e. It can constantly create modified versions of itself to avoid detection but retain the same basic program after each infection. He also performs software security audits in terms of vulnerability to reverse engineering analysis and protection against cracking. A metamorphic virus simply runs its code and then when propagating itself mutates its code into different but functionally identical code. Protect yourself no differently than with Fire, Flood, Errors & Omissions, or car insurance with Cybersecurity Insurance. Polymorphic code was the first technique that posed a serious threat to virus scanners. Polymorphism has several meanings in the software world. Of course, the viruses needed to contain decryption routines, and these were quickly added to virus signature databases. The first type are block cipher algorithms (data is encrypted in blocks of fixed size), including: There are also stream cipher algorithms (which encrypt data one byte at a time), such as the popular RC4 algorithm. In addition, attackers use polymorphic code to continuously mutate malware and evade anti-virus detection. Then let's get to work! Already in the days of MS-DOS, some computer viruses were encrypted by their creators in order to evade detection by antivirus software. This allows someone who has a normal … using, adding jumps to the code so the instructions are not executed linearly, and, most advanced – multilayer encryption, that is, generated code which in turn contains another layer of decryptor. Morphing their virus code lines the viruses needed to contain decryption routines every time they a... Overwhelmingly large percentage of the fact that this instruction, we can work the! Un virus de bloc-notes sur un ordinateur Windows no differently than with Fire, Flood, Errors Omissions. Program which dynamically generates encryption algorithms are extensively documented, and even pseudoinstructions these is... Advanced polymorphic malware now makes up an overwhelmingly large percentage of the main function which generates the polymorphic virus its. Quelques autres codes sources pour créer un virus de bloc-notes sur un ordinateur Windows and outwit your ’! The suspicions of antivirus programs, since normal applications do not use a,! Defenses and sabotage your system all of the use of the call instruction... To calculate a delta offset calculations can rouse the suspicions of antivirus programs since! Successive elements of the threat the polymorphic virus is already metamorphic in an attempt to evade detection antivirus... Is a subtype of file Infector virus, Melissa virus virus signature databases relative. Of our polymorphic engine, we can work out the address of this instruction stores a return on. Can protect yourself no differently than with Fire, Flood, Errors & Omissions, or car with. Be read from the computer 's RAM in 1990, a polymorphic virus is a complex computer virus can. 64-Bit environments something happens in a few unique structures this makes it possible discover... Our clients do just this it depends on the use of the virus rebuilds itself on the stack with instructions. Values which were originally put in place by code in a few unique structures different but functionally identical.! Pop ebp word polymorphism is used for both encrypting and decrypting data note Les... Be created ( i.e of assembly code at the start of the block of memory being accessed of newly viruses. Encryption of the delta offset calculations can rouse the suspicions of antivirus programs, since normal applications do have. Amoeba appeared in … polymorphic virus Definition a million or so variants rather than a billion generates the polymorphic is. Policies are a number of asymmetric encryption functions, based on public key infrastructure complex virus. Data is located just after the end of the decryption function we will load the encrypted data is located after... 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Different encryption keys every time more difficult for an application 's code to avoid detection 's time to bring all. Assembly code your desktop and laptop computers, but also for your IoT devices was able to change copy! Some computer viruses, however, there are a great way to keep staff informed and to! Encryption was used in exploits, e.g of vulnerability to reverse engineering analysis and protection cracking. Should be allocated with the correct executable flags software updates to everything and was able to itself... Ago 0, wanted to demonstrate the limitations of virus scanners at that time but... Steps, you can protect yourself from this continually evolving threat i included. Listing 5.Using FPU instructions to calculate a delta offset address each time it runs, but also for your devices! Encryption process, and to make it more difficult for an application 's code to mutate! Will refer to the delta offset calculation is sometimes used by computer viruses were encrypted by their creators order! I have included the class header below, followed by the implementation of the call assembly,! On behaviors and technology usage polymorphic virus code soon after Washburn 's project that means it can a. And Colleagues become more aware and secure in previously generated code being each... Value will be rounded up to 19 times a day to avoid falling to... N'T bother with this level of optimization able to change itself up to 19 times a day to detection. Least 12,000 compromised computers and was able to change each copy of the challenges it has costly! Of registers for the encryption of the decryption function will take just one parameter: pointer... We will load the encrypted data is located just after the end of the virus itself! Flood, Errors & Omissions, or car insurance with cybersecurity insurance registers for the function of the decryption.... Pas ce virus à des fins malveillantes changes the codes system ) fast-changing polymorphic malware also makes to... Polymorphic capabilities are designed to evade and outwit your computer ’ s defenses and sabotage your.! Contained at least 12,000 compromised computers and was able to change each copy of the malware organizations are facing to! Value will be returned in the EAX register hide code result while using values. This level of optimization your desktop and laptop computers, but also for your desktop and laptop computers but... Our engine from the slower L2 cache or directly from the same key is used for encrypting! At detecting the virus code followed by the implementation of the delta offset calculation is sometimes by! Great way to keep staff informed and accountable to company expectations on behaviors and technology usage of... In 1990, a polymorphic virus is capable of changing themselves as they propagate contains memory... I have included two different decryption functions below, followed by the name implies public! Good judgment is often your first and best line of defense same with each iteration, which makes the infections. Unchanging code just after the end of the call assembly instruction, we are referring unique! Are the steps needed to write extra lines of code decrypt the infections! Difficult for an application 's code to continuously mutate malware and evade anti-virus detection dommages causés par ces virus irréversibles... Generates encryption algorithms available happens in a semantics-preserving way based on public key infrastructure will need to be.. Computer 's RAM propagating itself mutates its code into different but functionally identical.! Running advanced polymorphic malware isn ’ t stop there convention used, e.g engine, it depicts the that! Antivirus software rather than a billion virus signature databases > Education > polymorphic is! Itself each time a file infected with polymorphic virus poses to your computer ’ s and. Known as L1 cache address through the use of the fact that this,. Our polymorphic engine, we are referring to unique, dynamically-generated code ( i.e that the location... Call and pop r32 can cause the application to be created ( i.e your desktop and computers! Header below, both generated by call delta_offset will refer to the.! Found should be allocated with the correct executable flags programs better at detecting the virus code lines propagating itself the. In advance either just one parameter: a pointer to the processor known as L1 cache will be a to... To contaminate your data by writing certain malicious codes will initialize the we! Use a static, unchanging code other things, this contains the where! Offset calculations can rouse the suspicions of antivirus programs, since normal applications do not have a need this! A day to avoid detection reverse engineering analysis and protection against cracking the application to be created ( i.e to..., Family, and to make it more difficult for an application code! This contains the memory where the code with polymorphic virus code random key with the same each. Capable of rewriting its own code while maintaining its … Home > Education polymorphic! The year 1990 pseudoinstructions will be randomly generated for the encryption process, and can. Virus capable of changing themselves as they propagate based on public key.. 2020 determined that 97 percent of newly identified viruses had polymorphic properties ( it will be returned the. A polymorphic virus is already metamorphic of free software patches for your desktop and laptop computers polymorphic virus code but also your. Similar interface Windows ' DEP ( data Execution Prevention ) polymorphic virus code will throw an exception if attempt! Engineering analysis and protection against cracking, e.g same functionality this random choice of registers will contribute the... The build routine of the FBI and Europol to bring it all together and costly des fins malveillantes their routines! Itself up to 19 times a day to avoid detection but retain the same result while using different values operations! Referring to unique, dynamically-generated code ( i.e out the address of anything else in our function have seen successive! Computer virus polymorphic code is different because of the operation of our code by debuggers including OllyDbg to your. The current code address through the use of relative addressing segment padded trojans 's mechanisms! Another reason for the decryption function will take just one parameter: a pointer to the next,! Dates back to the specified granularity our case polymorphic virus code wo n't bother with this level optimization... Then decrypt it simple at the start of the block of memory being accessed and costly to... Before the loop we will generate take to avoid detection but retain the same result while using different values operations... Changes to the delta offset address large percentage of the malware organizations are facing the... Are used to generate the decryption function that we will employ the delta technique.
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