Detecting Virtual Environment Files Sandbox Evasion

Some files are created by Virtualbox and VMware on the system.

Malware can check the different folders to find Virtualbox artifacts like VBoxMouse.sys.

Malware can check the different folders to find VMware artifacts like vmmouse.sys, vmhgfs.sys.

Some Files Example

Below is a list of files that can be detected on virtual machines:

"C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp\agent.pyw",

Checking Recent Office Files Sandbox Evasion

Another way to detect if the malware is running in a real user machine is to check if some recent Office files was opened.

Big File Antivirus/EDR Evasion

Because of the imposed file size limit, you can trick the scanner into skipping a file by changing the file’s size to make it larger than the hard-coded size limit. This file size limit applies especially with heuristic engines based on static data (data extracted from the portable executable, or PE, header). This is an old trick still apply in …

File Format Confusion Antivirus/EDR Evasion

By looking the structure of the PE and the content of the file, the engine is able to detect if the file is malicious or not. For example, an heuristic engine can try to figure out if a file are using a dual extension (e.g: invoice.doc.exe) and determine the file as being malicious.

Confusing file format is another trick …

File Splitting Antivirus/EDR Evasion

An old trick consists to split the malicious file into different parts and analyse all of them separately with and AV. The chunk where the detection is still being triggered is actually the part of the file that need to change to evade the antivirus software you are targeting.

FIleless Mechanisms Process Manipulating

Fileless malware is a type of malware that is designed to reside and execute entirely in the memory of a host system, without leaving any trace on the local disk. This can make it more difficult for security tools to detect and remove the malware, as it does not leave any files on the system that can be scanned or …

Image File Execution Options Injection Process Manipulating

Image File Execution Options Injection, also known as IFEO Injection, is a technique used by malware to evade detection and persist on a compromised system.

The technique involves modifying the Image File Execution Options (IFEO) registry key, which is used by the Windows operating system to set debugging options for executable files. When an executable file is launched, the …

NTFS Files Attributes Antivirus/EDR Evasion

Every New Technology File System (NTFS) formatted partition contains a Master File Table (MFT) that maintains a record for every file/directory on the partition. Within MFT entries are file attributes, such as Extended Attributes and Data known as Alternate Data Streams (ADSs) when more than one Data attribute is present], that can be used to store arbitrary data (and even …

File Melt Others

File melting is a technique that malware uses to delete itself after it has been installed on a system. This is often done in order to avoid detection by antivirus programs or other security measures. The process of file melting involves overwriting the file with random data, making it impossible to recover the original file or to detect the presence …

Windows File and Directory Permissions Modification Defense Evasion [Mitre]

Adversaries may modify file or directory permissions/attributes to evade access control lists (ACLs) and access protected files. File and directory permissions are commonly managed by ACLs configured by the file or directory owner, or users with the appropriate permissions. File and directory ACL implementations vary by platform, but generally explicitly designate which users or groups can perform which actions (read, …

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