macos malware runonly to avoid detection

#Macos malware runonly to avoid detection manual
#Macos malware runonly to avoid detection software
#Macos malware runonly to avoid detection code
#Macos malware runonly to avoid detection windows

#Macos malware runonly to avoid detection code

OSAMiner uses run-only AppleScripts to make it more difficult for its code to be reverse-engineered. This malware now uses multiple versions of AppleScript, a scripting language used to automate macOS actions, to improve obfuscation. The latest version of OSAMiner uses new techniques to evade detection.

#Macos malware runonly to avoid detection software

According to Sentinel Labs, OSAMiner has been active since 2015, spreading through compromised video games like League of Legends, and hacked versions of software packages such as Microsoft Office for macOS.

#Macos malware runonly to avoid detection manual

Nevertheless, manual analysis usually defeats packers.Researchers at Sentinel Labs have identified an updated version of OSAMiner, the cryptominer that targets the Mac operating system to mine Monero.

They are also the favorite tool of attackers for protecting malware. Packers remain an effective way to slow down analysis and decrease detection by antimalware products. This can be difficult because some packers add antidumping tricks. The fastest recovery technique is to run the malware and dump it directly from memory. To analyze them we must remove each layer until we recover the original file. Some malware use several layers to protect themselves against detection and analysis. Other packers will combine techniques such as anti-debugging or anti-sandbox and add more functions to protect the malware. To remove this kind of protection, a malware analyst must study the behavior and the byte code of the virtual software to retrieve and analyze the original file. Once the file is protected, the reversed code will be in the virtual machine’s byte code. The original file shows x86 assembly when reversed. This technique is one of the most difficult to analyze.Ī code virtualization packer. The original code is translated in the byte code of the virtual machine. This technique adds an abstraction layer between the executed code and its behavior. Still other techniques virtualize the code and emulate the behavior of a processor to run the original file. In some cases, the address of the API is located in the EIP register. A stub redirects the execution to the original API. In such cases, a malware analyst must fix the import by locating the function and tracing the return routine. The call is translated from the API to the stub and is run by the payload. The packer stub acts as a proxy and intercepts every call to the API.

Without the IAT, it is more difficult to correctly analyze malware because it cannot be properly disassembled.Ī packer obfuscating an API. Indeed, a memory dump does not work because the IAT is not complete. This protection increases the difficulty of unpacking the malware. During runtime the IAT is resolved dynamically and used by the program when necessary.

#Macos malware runonly to avoid detection windows

The IAT references functions that are used by a program and are available by the Windows API. Other packers act as a proxy and protect the import address table (IAT). The analyst has to retrieve it to recover the original file. In these cases the original entry point, the memory address where the program starts, is relocated in the packed section. Once the file is running, the decompression stub stored in the packed file will decompress the packed section. The original file is passed in the packer routine and stored in a packed section in the new. Advanced malware coded by organized cybercriminal groups, however, employ custom packers or implement complex protection inside malicious files.įor packers that encrypt or compress a file, a stub (a piece of code that contains the decompression or decryption routine) acts as a loader, which executes before the malware.Ī packer compresses or encrypts data. It is more convenient for attackers to use a packer rather than to directly implement protection inside the code. The complexity of packers varies.Ī packer can act simply as armor to protect the binary. Unpacking malware is the first challenge to understanding a threat. Packers can both make it harder for security staff to identify the behavior of malware and increase the amount of time required for an analysis. (Packers can also be used for legitimate ends, for example, to protect a program against cracking or copying.) All these tricks decrease the chance of detection by antimalware products and help to avoid analysis by security researchers. One of the most popular methods is to employ a packer, a tool that compresses, encrypts, and/or modifies a malicious file’s format.

Malware authors use a number of tricks to avoid detection and analysis.