SIDT, Red Pill

Created the Monday 11 March 2019. Updated 3 weeks ago.

Red Pill is a technique used by malware to determine whether it is running on a physical machine or a virtual machine. The Red Pill technique involves executing the SIDT instruction, which retrieves the value of the Interrupt Descriptor Table Register (IDTR) and stores it in a memory location.

On a physical machine, the IDTR will contain the address of the Interrupt Descriptor Table (IDT), which is a data structure used by the operating system to manage interrupts. However, on a virtual machine, the IDTR will contain the address of the IDT for the virtual machine, which is different from the IDT for the host machine.

By comparing the IDTR on a physical and a virtual machine, malware can determine whether it is running on a physical or a virtual machine. This information can be used by the malware to adjust its behavior accordingly.

Technique Identifiers

U1328 B0009.030

Technique Tags

Anti-VM technique SIDT instruction IDTR register IDT Interrupts Virtual machine Interrupt Descriptor Table (IDT)

Code Snippets

Description

In this code, we use inline assembly to execute the SIDT instruction, which retrieves the value of the IDTR and stores it in the idtr variable. We then check the value of the idtr variable, and if it is non-zero, we conclude that we are running on a virtual machine. In both cases, we print a message indicating the type of machine we are running on. Note that this code is for demonstration purposes only and may not work on all systems.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <inttypes.h>

int main()
{
    // Retrieve the value of the IDTR
    uint64_t idtr;
    asm volatile (
        "sidt %0"
        : "=m" (idtr)
    );

    // Check the value of the IDTR
    if (idtr != 0) {
        // We are running on a virtual machine
        printf("We are running on a virtual machine.\n");
    } else {
        // We are running on a physical machine
        printf("We are running on a physical machine.\n");
    }

    return 0;
}

Contributors

Additional Resources

External Links

The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.

https://litigationconferences.com/wp-content/uploads/2017/05/Introduction-to-Evasive-Techniques-v1.0.pdf