0x00401000

0x00401000 is a hexadecimal memory address often encountered in discussions of Windows 32-bit executables, particularly those packaged as Portable Executable (PE) files. In many contexts it represents the in-memory address of the program’s entry point when the image is loaded at its conventional base address.

In the PE format, the image base for many 32-bit Windows executables is 0x00400000. The PE header stores the entry point as an RVA (relative virtual address) of 0x00001000 in the AddressOfEntryPoint field. When the loader maps the image at its typical base, the actual virtual address of the entry point becomes image base plus RVA: 0x00400000 + 0x00001000 = 0x00401000. Thus 0x00401000 is commonly used to denote the entry point’s address in memory for such binaries.

It is important to distinguish between the virtual address (VA) and the raw file offset. The VA 0x00401000 reflects where code runs in memory, while the corresponding location on disk is determined by the section table and the PointerToRawData values. For many executables, the entry point RVA falls within the .text section, which might have a raw offset near 0x00001000, but this mapping depends on the specific binary and its section layout. Relocations and ASLR can cause the actual load address to differ from 0x00401000.

In practice, 0x00401000 is commonly observed as the startup point in debugging, reverse engineering, or malware analysis contexts for 32-bit Windows PE files. However, it is not universal and should be interpreted in the context of the specific binary’s headers and load configuration.