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Documentation

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VM::detect()

This is basically the main function you're looking for, which returns a bool. If the parameter is set to nothing, all the recommended checks will be performed. But you can optionally set what techniques are used.

#include "vmaware.hpp"

int main() {
    /**
     * The basic way to detect a VM where the default checks will 
     * be performed. This is the recommended usage of the library.
     */ 
    bool is_vm = VM::detect();


    /**
     * This does the exact same as above, but as an explicit alternative.
     */ 
    bool is_vm2 = VM::detect(VM::DEFAULT);


    /**
     * Essentially means only the CPU brand, MAC, and hypervisor bit techniques 
     * should be performed. Note that the less flags you provide, the more 
     * likely the result will not be accurate. If you just want to check for 
     * a single technique, use VM::check() instead. Also, read the flag table
     * at the end of this doc file for a full list of technique flags.
     */
    bool is_vm3 = VM::detect(VM::CPU_BRAND, VM::MAC, VM::HYPERVISOR_BIT);


    /**
     * There are roughly 1/3 of all techniques that are considered to be "spoofable",
     * meaning that anybody can potentially cause a false positive by exploiting the
     * fact that the "spoofable" techniques checks for things that anybody can modify
     * (file, registry, directories, etc...). This category of techniques are disabled 
     * by default, but they can be enabled with the VM::SPOOFABLE flag.
     */
    bool is_vm4 = VM::detect(VM::SPOOFABLE);


    /**
     * All checks are performed including SPOOFABLE techniques
     * and the cursor check, which waits 5 seconds for any human
     * mouse interaction to detect automated virtual environments.
     * If you're fine with having a 5 second delay, add VM::ALL 
     */ 
    bool is_vm5 = VM::detect(VM::ALL);


    /**
     * If you don't want the value to be memoized for whatever reason, 
     * you can set the VM::NO_MEMO flag and the result will not be cached. 
     * It's recommended to use this flag if you're only using one function
     * from the public interface a single time in total, so no unneccessary 
     * caching will be operated when you're not going to re-use the previously 
     * stored result at the end. 
     */ 
    bool is_vm6 = VM::detect(VM::NO_MEMO);


    /**
     * This will set the threshold bar to detect a VM higher than the default threshold.
     * Use this if you want to be extremely sure if it's a VM, but this can risk the result
     * to be a false negative. Use VM::percentage() for a more precise result if you want.
     */ 
    bool is_vm7 = VM::detect(VM::HIGH_THRESHOLD);


    /**
     * If you want to disable any technique for whatever reason, use VM::DISABLE(...).
     * This code snippet essentially means "perform all the default flags, but only 
     * disable the VM::RDTSC technique". 
     */ 
    bool is_vm8 = VM::detect(VM::DISABLE(VM::RDTSC));


    /**
     * Same as above, but you can disable multiple techniques at the same time.
     */ 
    bool is_vm9 = VM::detect(VM::DISABLE(VM::VMID, VM::RDTSC, VM::HYPERVISOR_BIT));


    /**
     * This is just an example to show that you can use a combination of different
     * flags and non-technique flags with the above examples. 
     */ 
    bool is_vm10 = VM::detect(VM::DEFAULT, VM::NO_MEMO, VM::HIGH_THRESHOLD, VM::DISABLE(VM::RDTSC, VM::VMID));

}

VM::percentage()

This will return a std::uint8_t between 0 and 100. It'll return the certainty of whether it has detected a VM based on all the techniques available as a percentage. The lower the value, the less chance it's a VM. The higher the value, the more likely it is.

#include "vmaware.hpp"
#include <iostream>
#include <cstdint>

int main() {
    // uint8_t and unsigned char works too
    const std::uint8_t percent = VM::percentage();

    if (percent == 100) {
        std::cout << "Definitely a VM!\n";
    } else if (percent == 0) {
        std::cout << "Definitely NOT a VM";
    } else {
        std::cout << "Unsure if it's a VM";
    }

    // converted to std::uint32_t for console character encoding reasons
    std::cout << "percentage: " << static_cast<std::uint32_t>(percent) << "%\n"; 
}

Note

you can use the same flag system as shown with VM::detect() for this function.


VM::brand()

This will essentially return the VM brand as a std::string. The exact possible brand string return values are:

  • VirtualBox
  • VMware
  • VMware Express
  • VMware ESX
  • VMware GSX
  • VMware Workstation
  • VMware Fusion
  • bhyve
  • QEMU
  • KVM
  • QEMU+KVM
  • KVM Hyper-V Enlightenment
  • QEMU+KVM Hyper-V Enlightenment
  • Virtual PC
  • Microsoft Hyper-V
  • Microsoft Virtual PC/Hyper-V
  • Microsoft x86-to-ARM
  • Parallels
  • Xen HVM
  • ACRN
  • QNX hypervisor
  • Hybrid Analysis
  • Sandboxie
  • Docker
  • Wine
  • Virtual Apple
  • Anubis
  • JoeBox
  • ThreatExpert
  • CWSandbox
  • Comodo
  • Bochs
  • Lockheed Martin LMHS (yes, you read that right. The library can detect VMs running on US military fighter jets)
  • NVMM
  • OpenBSD VMM
  • Intel HAXM
  • Unisys s-Par
  • Cuckoo
  • BlueStacks
  • Jailhouse
  • Apple VZ
  • Intel KGT (Trusty)
  • Microsoft Azure Hyper-V
  • Xbox NanoVisor (Hyper-V)
  • SimpleVisor
  • Hyper-V artifact (not an actual VM)
  • User-mode Linux
  • IBM PowerVM
  • Google Compute Engine (KVM)
  • OpenStack (KVM)
  • KubeVirt (KVM)
  • AWS Nitro System (KVM-based)
  • Podman
  • WSL
  • OpenVZ
  • ANY.RUN

If none were detected, it will return Unknown. It's often NOT going to produce a satisfying result due to technical difficulties with accomplishing this, on top of being highly dependent on what mechanisms detected a VM. This is especially true for VMware sub-versions (ESX, GSX, Fusion, etc...) Don't rely on this function for critical operations as if it's your golden bullet. It's arguably unreliable and it'll most likely return Unknown (assuming it is actually running under a VM).

#include "vmaware.hpp"
#include <string>

int main() {
    const std::string result = VM::brand();

    if (result == "KVM") {
        // do KVM specific stuff
    } else if (result == "VirtualBox") {
        // do vbox specific stuff
    } else {
        // you get the idea
    }
}

On rare occasions, there might be cases where there's multiple brands that have been detected, which might cause a conflicting output with an inaccurate result. To prevent this, you can use the VM::MULTIPLE flag that returns a message rather than a VM brand string. For example, if it found 2 conflicting brands, it will return VMware or VirtualBox. For 3 conflicts, it's VMware or VirtualBox or QEMU and so on.

#include "vmaware.hpp"
#include <string>

int main() {
    // format: "vmbrand1 or vmbrand2 [or vmbrandx...]"
    const std::string result = VM::brand(VM::MULTIPLE);

    // example output: "VMware or Bochs"
    std::cout << result << "\n";

    // Keep in mind that there's no limit to how many conflicts there can be.
    // And if there's no conflict, it'll revert back to giving the brand string
    // normally as if the VM::MULTIPLE wasn't there
}

Note

you can use the same flag system as shown with VM::detect() for VM::brand()

Important

VM::MULTIPLE has no effect for any other function other than VM::brand()


VM::check()

This takes a single flag argument and returns a bool. It's essentially the same as VM::detect() but it doesn't have a scoring system. It only returns the technique's effective output. The reason why this exists is because it allows end-users to have fine-grained control over what is being executed and what isn't.

VM::detect() is meant for a range of techniques to be evaluated in the bigger picture with weights and biases in its scoring system, while VM::check() is meant for a single technique to be evaluated without any weights or anything extra. It very simply just gives you what the technique has found on its own. For example:

#include "vmaware.hpp"
#include <iostream>

int main() {
    if (VM::check(VM::VMID)) {
        std::cout << "VMID technique detected a VM!\n";
    }

    if (VM::check(VM::HYPERVISOR_BIT)) {
        std::cout << "Hypervisor bit is set, most definitely a VM!\n";
    }
}

VM::add_custom()

This function allows you to add your own custom VM detection techniques to the scoring system. The first parameter is the percentage score (0 to 100) of how likely it's a VM if your custom code returns true, and the second parameter should either be a lambda, a function pointer, or a std::function<bool()>

// Example 1 with function pointers

bool new_technique() {
    // add your VM detection code here
    return true; 
}

VM::add_custom(50, new_technique);
// Example 2 with lambdas

VM::add_custom(50, []() -> bool { 
    // add your VM detection code here
    return true; 
});

auto new_technique = []() -> bool { 
    // add your VM detection code here
    return true;
}

VM::add_custom(50, new_technique);
// Example 3 with std::function

std::function<bool()> new_technique = []() -> bool {
    // add your VM detection code here
    return true;
};

VM::add_custom(50, new_technique);

VM::type()

This will return the VM type as a std::string based on the brand found. The possible return values can be:

  • Hypervisor (type 1)
  • Hypervisor (type 2)
  • Sandbox
  • Emulator
  • Emulator/Hypervisor (type 2)
  • Partitioning Hypervisor
  • Container
  • Hypervisor (either type 1 or 2)
  • Hypervisor (unknown type)
  • Compatibility layer
  • Paravirtualised/Hypervisor (type 2)
  • Hybrid Hyper-V (type 1 and 2)
  • Binary Translation Layer/Emulator
  • Unknown

VM::conclusion()

This will return the "conclusion" message of what the overall result is as a std::string. The [brand] part might contain a brand or may as well be empty, depending on whether a brand has been found.

  • Running in baremetal
  • Very unlikely a [brand] VM
  • Unlikely a [brand] VM
  • Potentially a [brand] VM
  • Might be a [brand] VM
  • Likely a [brand] VM
  • Very likely a [brand] VM
  • Running inside a [brand] VM

vmaware struct

If you prefer having an object to store all the relevant information about the program's environment instead of calling static member functions, you can use the VM::vmaware struct:

struct vmaware {
    std::string brand;
    std::string type;
    std::string conclusion;
    bool is_vm;
    std::uint8_t percentage;
    std::uint8_t detected_count;
    std::uint8_t technique_count;
}; 

example:

#include "vmaware.hpp"
#include <iostream>

int main() {
    VM::vmaware vm;

    std::cout << "Is this a VM? = " << vm.is_vm << "\n";
    std::cout << "How many techniques detected a VM? = " << vm.detected_count << "%\n";
    std::cout << "What's the overview in a human-readable message?" << vm.conclusion << "\n";
}

Note

the flag system is compatible for the struct constructor.


Flag table

VMAware provides a convenient way to not only check for VMs, but also have the flexibility and freedom for the end-user to choose what techniques are used with complete control over what gets executed or not. This is handled with a flag system.

Flag alias Description Cross-platform? (empty = yes) Certainty Admin? GPL-3.0? 32-bit only? Spoofable? Notes
VM::VMID Check CPUID output of manufacturer ID for known VMs/hypervisors at leaf 0 100%
VM::CPU_BRAND Check if CPU brand model contains any VM-specific string snippets 50%
VM::HYPERVISOR_BIT Check if hypervisor feature bit in CPUID eax bit 31 is enabled (always false for physical CPUs) 100%
VM::HYPERVISOR_STR Check for hypervisor brand string length (would be around 2 characters in a host machine) 45%
VM::RDTSC Benchmark RDTSC and evaluate its speed, usually it's very slow in VMs Linux and Windows 10% Disabled by default
VM::THREADCOUNT Check if there are only 1 or 2 threads, which is a common pattern in VMs with default settings (nowadays physical CPUs should have at least 4 threads for modern CPUs) 35%
VM::MAC Check if mac address starts with certain VM designated values Linux and Windows 60% Spoofable
VM::TEMPERATURE Check if thermal directory in linux is present, might not be present in VMs Linux 15%
VM::SYSTEMD Check result from systemd-detect-virt tool Linux 70%
VM::CVENDOR Check if the chassis vendor is a VM vendor Linux 65%
VM::CTYPE Check if the chassis type is valid (it's very often invalid in VMs) Linux 10%
VM::DOCKERENV Check if /.dockerenv or /.dockerinit file is present Linux 80% Spoofable
VM::DMIDECODE Check if dmidecode output matches a VM brand Linux 55% Admin
VM::DMESG Check if dmesg output matches a VM brand Linux 55% Admin
VM::HWMON Check if /sys/class/hwmon/ directory is present. If not, likely a VM Linux 75% Spoofable
VM::SIDT5 Check if the 5th byte after sidt is null Linux 45%
VM::CURSOR Check if cursor isn't active for 5 seconds (sign of automated VM environment) Windows 5% Spoofable Disabled by default
VM::VMWARE_REG Check for VBox RdrDN Windows 65% Spoofable
VM::VBOX_REG Look for any VirtualBox-specific registry data Windows 65% Spoofable
VM::USER checks for default usernames, often a sign of a VM Windows 35% Spoofable
VM::DLL Check for VM-specific DLLs Windows 50% Spoofable
VM::REGISTRY Check for VM-specific registry values Windows 75% Spoofable
VM::CWSANDBOX_VM Check if CWSandbox-specific file exists Windows 10% Spoofable
VM::VM_FILES Find for VMware and VBox specific files Windows 10% Spoofable
VM::HWMODEL Check if the sysctl for the hwmodel does not contain the "Mac" string MacOS 75% Spoofable
VM::DISK_SIZE Check if disk size is under or equal to 50GB Linux 60%
VM::VBOX_DEFAULT Check for default RAM and DISK sizes set by VirtualBox Linux and Windows 55% Admin
VM::VBOX_NETWORK Check for VirtualBox network provider string Windows 70%
VM::COMPUTER_NAME Check if the computer name (not username to be clear) is VM-specific Windows 40% GPL Spoofable
VM::WINE_CHECK Check wine_get_unix_file_name file for Wine Windows 85% GPL
VM::HOSTNAME Check if hostname is specific Windows 25% GPL Spoofable
VM::MEMORY Check if memory space is far too low for a physical machine Windows 35% GPL
VM::VBOX_WINDOW_CLASS Check for the window class for VirtualBox Windows 10% GPL
VM::LOADED_DLLS Check for loaded DLLs in the process Windows 75% GPL Spoofable
VM::KVM_REG Check for KVM-specific registry strings Windows 75% GPL Spoofable
VM::KVM_DRIVERS Check for KVM-specific .sys files in system driver directory Windows 55% GPL Spoofable
VM::KVM_DIRS Check for KVM directory "Virtio-Win" Windows 55% GPL Spoofable
VM::AUDIO Check if audio device is present Windows 35% GPL
VM::QEMU_DIR Check for QEMU-specific blacklisted directories Windows 45% GPL Spoofable
VM::MOUSE_DEVICE Check for the presence of a mouse device Windows 20% GPL Spoofable
VM::VM_PROCESSES Check for any VM processes that are active Windows 30% Spoofable
VM::LINUX_USER_HOST Check for default VM username and hostname for linux Linux 25% Spoofable
VM::GAMARUE Check for Gamarue ransomware technique which compares VM-specific Window product IDs Windows 40% Spoofable
VM::VMID_0X4 Check if the CPU manufacturer ID matches that of a VM brand with leaf 0x40000000 100%
VM::PARALLELS_VM Check for any indication of Parallels VM through BIOS data Windows 50%
VM::RDTSC_VMEXIT check through alternative RDTSC technique with VMEXIT 25% Disabled by default
VM::QEMU_BRAND Match for QEMU CPU brands with "QEMU Virtual CPU" string 100%
VM::BOCHS_CPU Check for various Bochs-related emulation oversights through CPU checks 95%
VM::VPC_BOARD Check through the motherboard and match for VirtualPC-specific string Windows 20%
VM::HYPERV_WMI Check WMI query for "Hyper-V RAW" string Windows 80%
VM::HYPERV_REG Check presence for Hyper-V specific string in registry Windows 80% Spoofable
VM::BIOS_SERIAL Check if the BIOS serial is valid (null = VM) Windows 60%
VM::VBOX_FOLDERS Check for VirtualBox-specific string for shared folder ID Windows 45%
VM::MSSMBIOS Check MSSMBIOS registry for VM-specific strings Windows 75%
VM::MAC_MEMSIZE Check if memory is too low for MacOS system MacOS 30% Spoofable
VM::MAC_IOKIT Check MacOS' IO kit registry for VM-specific strings MacOS 80% Spoofable
VM::IOREG_GREP Check for VM-strings in ioreg commands for MacOS MacOS 75% Spoofable
VM::MAC_SIP Check if System Integrity Protection is disabled (likely a VM if it is) MacOS 85% Spoofable
VM::HKLM_REGISTRIES Check HKLM registries for specific VM strings Windows 70% Spoofable
VM::QEMU_GA Check for "qemu-ga" process Linux 20% Spoofable
VM::VALID_MSR check for valid MSR value 0x40000000 Windows 35%
VM::QEMU_PROC Check for QEMU processes Windows 30% Spoofable
VM::VPC_PROC Check for VPC processes Windows 30% Spoofable
VM::VPC_INVALID Check for official VPC method Windows 75% 32-bit
VM::SIDT Check for sidt instruction method Linux, Windows 30%
VM::SGDT Check for sgdt instruction method Windows 30% 32-bit
VM::SLDT Check for sldt instruction method Windows 15% 32-bit
VM::OFFSEC_SIDT Check for Offensive Security SIDT method Windows 60% 32-bit
VM::OFFSEC_SGDT Check for Offensive Security SGDT method Windows 60% 32-bit
VM::OFFSEC_SLDT Check for Offensive Security SLDT method Windows 20% 32-bit
VM::HYPERV_BOARD Check for Hyper-V specific string in motherboard Windows 45%
VM::VM_FILES_EXTRA Check for VPC and Parallels files Windows 70% Spoofable
VM::VPC_SIDT Check for sidt method with VPC's 0xE8XXXXXX range Windows 15% 32-bit
VM::VMWARE_IOMEM Check for VMware string in /proc/iomem Linux 65%
VM::VMWARE_IOPORTS Check for VMware string in /proc/ioports Linux 70%
VM::VMWARE_SCSI Check for VMware string in /proc/scsi/scsi Linux 40%
VM::VMWARE_DMESG Check for VMware-specific device name in dmesg output Linux 65% Admin
VM::VMWARE_STR Check str assembly instruction method for VMware Windows 35%
VM::VMWARE_BACKDOOR Check for official VMware io port backdoor technique Windows 100% 32-bit
VM::VMWARE_PORT_MEM Check for VMware memory using IO port backdoor Windows 85% 32-bit
VM::SMSW Check for SMSW assembly instruction technique Windows 30% 32-bit
VM::MUTEX Check for mutex strings of VM brands Windows 85%
VM::UPTIME Check if uptime is less than or equal to 2 minutes 10% Spoofable
VM::ODD_CPU_THREADS Check for odd CPU threads, usually a sign of modification through VM setting because 99% of CPUs have even numbers of threads 80%
VM::INTEL_THREAD_MISMATCH Check for Intel CPU thread count database if it matches the system's thread count 60%
VM::XEON_THREAD_MISMATCH Same as above, but for Xeon Intel CPUs 85%
VM::NETTITUDE_VM_MEMORY Check for memory regions to detect VM-specific brands Windows 75%
VM::CPUID_BITSET Check for CPUID technique by checking whether all the bits equate to more than 4000 20%
VM::CUCKOO_DIR Check for cuckoo directory using crt and WIN API directory functions Windows 15% Spoofable
VM::CUCKOO_PIPE Check for Cuckoo specific piping mechanism Windows 20% Spoofable
VM::HYPERV_HOSTNAME Check for default Azure hostname format regex (Azure uses Hyper-V as their base VM brand) Windows, Linux 50% Spoofable
VM::GENERAL_HOSTNAME Check for commonly set hostnames by certain VM brands Windows, Linux 20% Spoofable
VM::SCREEN_RESOLUTION Check for pre-set screen resolutions commonly found in VMs Windows 10%
VM::DEVICE_STRING Check if bogus device string would be accepted Windows 25%
VM::BLUESTACKS_FOLDERS Check for the presence of BlueStacks-specific folders Linux 15% Spoofable
VM::CPUID_SIGNATURE Check for signatures in leaf 0x40000001 in CPUID 95%
VM::HYPERV_BITMASK Check for Hyper-V CPUID bitmask range for reserved values 20%
VM::KVM_BITMASK Check for KVM CPUID bitmask range for reserved values 40%
VM::KGT_SIGNATURE Check for Intel KGT (Trusty branch) hypervisor signature in CPUID 80%
VM::VMWARE_DMI Check for VMware DMI strings in BIOS serial number Windows 30%
VM::EVENT_LOGS Check for presence of Hyper-V in the Windows Event Logs Windows 30% Spoofable
VM::QEMU_VIRTUAL_DMI Check for presence of QEMU in the /sys/devices/virtual/dmi/id directory Linux 40%
VM::QEMU_USB Check for presence of QEMU in the /sys/kernel/debug/usb/devices directory Linux 20%
VM::HYPERVISOR_DIR Check for presence of any files in /sys/hypervisor directory Linux 20%
VM::UML_CPU Check for the "UML" string in the CPU brand Linux 80%
VM::KMSG Check for any indications of hypervisors in the kernel message logs Linux 10% Spoofable
VM::VM_PROCS Check for a Xen VM process Linux 20% Spoofable
VM::VBOX_MODULE Check for a VBox kernel module Linux 15%
VM::SYSINFO_PROC Check for potential VM info in /proc/sysinfo Linux 15%
VM::DEVICE_TREE Check for specific files in /proc/device-tree directory Linux 20%
VM::DMI_SCAN Check for string matches of VM brands in the linux DMI Linux 50%
VM::SMBIOS_VM_BIT Check for the VM bit in the SMBIOS data Linux 50%
VM::PODMAN_FILE Check for podman file in /run/ Linux 15% Spoofable
VM::WSL_PROC Check for WSL or microsoft indications in /proc/ subdirectories Linux 30%
VM::ANYRUN_DRIVER Check for any.run driver presence Windows 65%
VM::ANYRUN_DIRECTORY Check for any.run directory and handle the status code Windows 35%

Non-technique flags

Flag Description
VM::ALL This will enable all the technique flags, including spoofable techniques and cursor check that are disabled by default.
VM::NO_MEMO This will disable memoization, meaning the result will not be fetched through a previous computation of the VM::detect() function. Use this if you're only using a single function from the VM struct for a performance boost.
VM::DEFAULT This represents a range of flags which are enabled if no default argument is provided.
VM::MULTIPLE This is specific to VM::brand(). This will basically return a std::string message of what brands could be involved. For example, it could return "VMware or VirtualBox" instead of having a single brand string output. This has no effect if applied to any other functions than VM::brand().
VM::HIGH_THRESHOLD This is specific to VM::detect() and VM::percentage(), which will set the threshold bar to confidently detect a VM by 3x higher.
VM::SPOOFABLE This will enable all the "spoofable" techniques (which are 1/3 of the total amount of techniques)

Variables

Variable Type Description
VM::technique_count std::uint8_t This will store the number of VM detection techniques
VM::technique_vector std::vector<std::uint8_t> This will store all the technique macros as a vector. Useful if you're trying to loop through all the techniques for whatever operation you're performing.

CLI documentation

Shorthand Full command Description
-h --help Prints the help menu
-v --version Prints the version and miscellaneous details
-d --detect Prints the VM detection result (1 = VM, 0 = baremetal)
-s --stdout Returns either 0 or 1 to STDOUT without any text output (0 = VM, 1 = baremetal)
-b --brand Prints the most likely brand
-l --brand-list Prints all the possible VM brand strings the CLI supports
-c --conclusion Prints the conclusion message string
-p --percent Prints the VM likeliness percentage between 0 and 100
-n --number Prints the number of VM detection techniques it can performs
-t --type Returns the VM type (if a VM was found)
--disable-notes No notes will be provided
--spoofable Allow spoofable techniques to be ran (not included by default)

Note

If you want a general result of everything combined above, do not put any arguments. This is the intended way to use the CLI tool.