The No Pill technique is a method used by malware to determine whether it is running on a physical machine or a virtual machine. This technique relies on the fact that the Local Descriptor Table (LDT) is assigned to a processor, rather than to an operating system. On a physical machine, the location of the LDT will be zero, whereas on a virtual machine, the location of the LDT will be non-zero.

By checking the location of the LDT, 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. For example, the malware may choose to remain dormant on a virtual machine in order to avoid detection.