u, u2 (disassemble virtual address)

Description of 'u, u2' command in HyperDbg.

Command

u

u2

Syntax

u [address] l [length (hex)] pid [process id (hex)]

u2 [address] l [length (hex)] pid [process id (hex)]

u disassembles as x64, and u2 disassembles as x86.

Description

Shows the assembly regarding memory content at the virtual address hex form.

Parameters

[Address]

The virtual address of where we want to start to disassemble its memory

l [Length] (optional)

The length (byte) in hex format

pid [process id] (optional)

The process ID in hex format that we want to see the memory from its context (cr3).

If you don't specify the pid, then the default pid is the current process (HyperDbg) process layout of memory.

Examples

The following command is used when we want to disassemble the content of memory (x64) at fffff800`3ad6f010 with length of 0x50 bytes from the memory layout view of process (4 a.k.a. system process).

HyperDbg> u fffff800`3ad6f010 l 50 pid 4
fffff800`3ad6f010 48 89 5C 24 08 mov qword ptr ss:[rsp+0x08], rbx
fffff800`3ad6f015 48 89 6C 24 10 mov qword ptr ss:[rsp+0x10], rbp
fffff800`3ad6f01a 48 89 74 24 18 mov qword ptr ss:[rsp+0x18], rsi
fffff800`3ad6f01f 57 push rdi
fffff800`3ad6f020 41 56 push r14
fffff800`3ad6f022 41 57 push r15
fffff800`3ad6f024 48 83 EC 30 sub rsp, 0x30
fffff800`3ad6f028 65 48 8B 04 25 20 00 00 00 mov rax, qword ptr gs:[0x0000000000000020]
fffff800`3ad6f031 33 DB xor ebx, ebx
fffff800`3ad6f033 44 0F B7 3D C5 3F 20 00 movzx r15d, word ptr ds:[0xFFFFF8003AF73000]
fffff800`3ad6f03b 41 8B E8 mov ebp, r8d
fffff800`3ad6f03e 48 8B F2 mov rsi, rdx
fffff800`3ad6f041 89 5C 24 68 mov dword ptr ss:[rsp+0x68], ebx
fffff800`3ad6f045 8B F9 mov edi, ecx
fffff800`3ad6f047 4C 8B 88 C0 00 00 00 mov r9, qword ptr ds:[rax+0xC0]
fffff800`3ad6f04e 45 0F B7 B1 92 00 00 00 movzx r14d, word ptr ds:[r9+0x92]
fffff800`3ad6f056 41 8B C6 mov eax, r14d
fffff800`3ad6f059 44 8B C8 mov r9d, eax
fffff800`3ad6f05c 89 5C 24 20 mov dword ptr ss:[rsp+0x20], ebx

The following example shows the assembly content (x64) of memory at fffff800`3ad6f010 from current process memory layout.

HyperDbg> u fffff800`3ad6f010
fffff800`3ad6f010 48 89 5C 24 08 mov qword ptr ss:[rsp+0x08], rbx
fffff800`3ad6f015 48 89 6C 24 10 mov qword ptr ss:[rsp+0x10], rbp
fffff800`3ad6f01a 48 89 74 24 18 mov qword ptr ss:[rsp+0x18], rsi
fffff800`3ad6f01f 57 push rdi
fffff800`3ad6f020 41 56 push r14
fffff800`3ad6f022 41 57 push r15
fffff800`3ad6f024 48 83 EC 30 sub rsp, 0x30
fffff800`3ad6f028 65 48 8B 04 25 20 00 00 00 mov rax, qword ptr gs:[0x0000000000000020]
fffff800`3ad6f031 33 DB xor ebx, ebx
fffff800`3ad6f033 44 0F B7 3D C5 3F 20 00 movzx r15d, word ptr ds:[0xFFFFF8003AF73000]
fffff800`3ad6f03b 41 8B E8 mov ebp, r8d
fffff800`3ad6f03e 48 8B F2 mov rsi, rdx
fffff800`3ad6f041 89 5C 24 68 mov dword ptr ss:[rsp+0x68], ebx
fffff800`3ad6f045 8B F9 mov edi, ecx
fffff800`3ad6f047 4C 8B 88 C0 00 00 00 mov r9, qword ptr ds:[rax+0xC0]

IOCTL

This function works by calling DeviceIoControl with IOCTL = IOCTL_DEBUGGER_READ_MEMORY , you have to send it in the following structure.

typedef struct _DEBUGGER_READ_MEMORY {
UINT32 Pid; // Read from cr3 of what process
UINT64 Address;
UINT32 Size;
DEBUGGER_READ_MEMORY_TYPE MemoryType;
DEBUGGER_READ_READING_TYPE ReadingType;
} DEBUGGER_READ_MEMORY, * PDEBUGGER_READ_MEMORY;

Where Pid is the process id, Address is the target location address and size is the length of the byte that you need to read.

MemoryTypeis either virtual or physical.

typedef enum _DEBUGGER_READ_MEMORY_TYPE { DEBUGGER_READ_PHYSICAL_ADDRESS, DEBUGGER_READ_VIRTUAL_ADDRESS } DEBUGGER_READ_MEMORY_TYPE;

ReadingType is either from the kernel or from the vmx root. Currently, only the reading from the kernel is implemented.

typedef enum _DEBUGGER_READ_READING_TYPE { READ_FROM_KERNEL, READ_FROM_VMX_ROOT } DEBUGGER_READ_READING_TYPE;

If you don't want to read from the kernel directly, use the following HyperDbg Routine.

void HyperDbgReadMemoryAndDisassemble(DEBUGGER_SHOW_MEMORY_STYLE Style, UINT64 Address,
DEBUGGER_READ_MEMORY_TYPE MemoryType,
DEBUGGER_READ_READING_TYPE ReadingType, UINT32 Pid,
UINT Size);

The above function fills the IOCTL structure and shows the memory content. It is also able to disassemble the memory. You can specify one of the following styles to show the memory.

typedef enum _DEBUGGER_SHOW_MEMORY_STYLE { DEBUGGER_SHOW_COMMAND_DISASSEMBLE64, DEBUGGER_SHOW_COMMAND_DISASSEMBLE32, DEBUGGER_SHOW_COMMAND_DB, DEBUGGER_SHOW_COMMAND_DC, DEBUGGER_SHOW_COMMAND_DQ, DEBUGGER_SHOW_COMMAND_DD } DEBUGGER_SHOW_MEMORY_STYLE;

For disassembling, use the DEBUGGER_SHOW_COMMAND_DISASSEMBLE64 as the Style for x64 disassembling and for disassembling x86, use the DEBUGGER_SHOW_COMMAND_DISASSEMBLE32.

Remarks

  • If you don't specify the length, the default length for HyperDbg is 0x40 Bytes.

Please note that you should specify space between 'l' and the length for HyperDbg. For example, 'l10' is invalid, but 'l 10' is valid. (It's opposed to windbg).

HyperDbg uses Zydis as its core disassembler.

This command is guaranteed to keep debuggee in a halt state (in Debugger Mode); thus, nothing will change during its execution.

Requirements

None

Zydis

!u (disassemble physical address)