HyperDbg Documentation
CommunityDownloadResearchTutorialhwdbg
  • HyperDbg
  • Getting Started
    • Quick Start
    • FAQ
    • Build & Install
    • Attach to HyperDbg
      • Attach to a remote machine
      • Attach to local machine
      • Start a new process
      • Attach to a running process
  • Using HyperDbg
    • Prerequisites
      • Operation Modes
      • How to create a condition?
      • How to create an action?
      • Signatures
    • User-mode Debugging
      • Principles
      • Examples
        • basics
        • events
          • Getting Results of a System-call
    • Kernel-mode Debugging
      • Principles
      • Examples
        • beginning
          • Connecting To HyperDbg
          • Configuring Symbol Server/Path
        • basics
          • Setting Breakpoints & Stepping Instructions
          • Displaying & Editing & Searching Memory
          • Showing & Modifying Registers and Flags
          • Switching to a Specific Process or Thread
          • Mapping Data & Create Structures, and Enums From Symbols
        • events
          • Managing Events
          • Hooking Any Function
          • Intercepting All SYSCALLs
          • Monitoring Accesses To Structures
          • Triggering Special Instructions
          • Identifying System Behavior
        • Scripting Language Examples
    • Software Development Kit (SDK)
      • Events
        • Conditions
        • Actions
      • IOCTL
        • Event Registration
  • Commands
    • Debugging Commands
      • ? (evaluate and execute expressions and scripts in debuggee)
      • ~ (display and change the current operating core)
      • a (assemble virtual address)
      • load (load the kernel modules)
      • unload (unload the kernel modules)
      • status (show the debuggee status)
      • events (show and modify active/disabled events)
      • p (step-over)
      • t (step-in)
      • i (instrumentation step-in)
      • gu (step-out or go up)
      • r (read or modify registers)
      • bp (set breakpoint)
      • bl (list breakpoints)
      • be (enable breakpoints)
      • bd (disable breakpoints)
      • bc (clear and remove breakpoints)
      • g (continue debuggee or processing kernel packets)
      • x (examine symbols and find functions and variables address)
      • db, dc, dd, dq (read virtual memory)
      • eb, ed, eq (edit virtual memory)
      • sb, sd, sq (search virtual memory)
      • u, u64, u2, u32 (disassemble virtual address)
      • k, kd, kq (display stack backtrace)
      • dt (display and map virtual memory to structures)
      • struct (make structures, enums, data types from symbols)
      • sleep (wait for specific time in the .script command)
      • pause (break to the debugger and pause processing kernel packets)
      • print (evaluate and print expression in debuggee)
      • lm (view loaded modules)
      • cpu (check cpu supported technologies)
      • rdmsr (read model-specific register)
      • wrmsr (write model-specific register)
      • flush (remove pending kernel buffers and messages)
      • prealloc (reserve pre-allocated pools)
      • preactivate (pre-activate special functionalities)
      • output (create output source for event forwarding)
      • test (test functionalities)
      • settings (configures different options and preferences)
      • exit (exit from the debugger)
    • Meta Commands
      • .help (show the help of commands)
      • .debug (prepare and connect to debugger)
      • .connect (connect to a session)
      • .disconnect (disconnect from a session)
      • .listen (listen on a port and wait for the debugger to connect)
      • .status (show the debugger status)
      • .start (start a new process)
      • .restart (restart the process)
      • .attach (attach to a process)
      • .detach (detach from the process)
      • .switch (show the list and switch between active debugging processes)
      • .kill (terminate the process)
      • .process, .process2 (show the current process and switch to another process)
      • .thread, .thread2 (show the current thread and switch to another thread)
      • .pagein (bring the page into the RAM)
      • .dump (save the virtual memory into a file)
      • .formats (show number formats)
      • .script (run batch script commands)
      • .sympath (set the symbol server)
      • .sym (load pdb symbols)
      • .pe (parse PE file)
      • .logopen (open log file)
      • .logclose (close log file)
      • .cls (clear the screen)
    • Extension Commands
      • !a (assemble physical address)
      • !pte (display page-level address and entries)
      • !db, !dc, !dd, !dq (read physical memory)
      • !eb, !ed, !eq (edit physical memory)
      • !sb, !sd, !sq (search physical memory)
      • !u, !u64, !u2, !u32 (disassemble physical address)
      • !dt (display and map physical memory to structures)
      • !track (track and map function calls and returns to the symbols)
      • !epthook (hidden hook with EPT - stealth breakpoints)
      • !epthook2 (hidden hook with EPT - detours)
      • !monitor (monitor read/write/execute to a range of memory)
      • !syscall, !syscall2 (hook system-calls)
      • !sysret, !sysret2 (hook SYSRET instruction execution)
      • !mode (detect kernel-to-user and user-to-kernel transitions)
      • !cpuid (hook CPUID instruction execution)
      • !msrread (hook RDMSR instruction execution)
      • !msrwrite (hook WRMSR instruction execution)
      • !tsc (hook RDTSC/RDTSCP instruction execution)
      • !pmc (hook RDPMC instruction execution)
      • !vmcall (hook hypercalls)
      • !exception (hook first 32 entries of IDT)
      • !interrupt (hook external device interrupts)
      • !dr (hook access to debug registers)
      • !ioin (hook IN instruction execution)
      • !ioout (hook OUT instruction execution)
      • !hide (enable transparent-mode)
      • !unhide (disable transparent-mode)
      • !measure (measuring and providing details for transparent-mode)
      • !va2pa (convert a virtual address to physical address)
      • !pa2va (convert physical address to virtual address)
      • !dump (save the physical memory into a file)
      • !pcitree (show PCI/PCIe device tree)
      • !pcicam (dump the PCI/PCIe configuration space)
      • !idt (show Interrupt Descriptor Table entries)
      • !apic (dump local APIC entries in XAPIC and X2APIC modes)
      • !ioapic (dump I/O APIC)
    • Scripting Language
      • Assumptions & Evaluations
      • Variables & Assignments
      • Casting & Type-awareness
      • Conditionals & Loops
      • Constants & Functions
      • Debugger Script (DS)
      • Examples
        • view system state (registers, memory, variables)
        • change system state (registers, memory, variables)
        • trace function calls
        • pause the debugger conditionally
        • conditional breakpoints and events
        • patch the normal sequence of execution
        • access to a shared variable from different cores
        • count occurrences of events
      • Functions
        • debugger
          • pause
        • events
          • event_enable
          • event_disable
          • event_clear
          • event_sc
          • event_inject
          • event_inject_error_code
          • flush
        • exports
          • print
          • printf
        • interlocked
          • interlocked_compare_exchange
          • interlocked_decrement
          • interlocked_exchange
          • interlocked_exchange_add
          • interlocked_increment
        • memory
          • check_address
          • eb, ed, eq
          • eb_pa, ed_pa, eq_pa
          • memcpy
          • memcpy_pa
          • memcmp
          • virtual_to_physical
          • physical_to_virtual
        • diassembler
          • disassemble_len
          • disassemble_len32
        • spinlocks
          • spinlock_lock
          • spinlock_lock_custom_wait
          • spinlock_unlock
        • strings
          • strlen
          • wcslen
          • strcmp
          • strncmp
          • wcscmp
          • wcsncmp
    • Commands Map
  • Tips & Tricks
    • Considerations
      • Basic concepts in Intel VT-x
      • VMX root-mode vs VMX non-root mode
      • The "unsafe" behavior
      • Script engine in VMX non-root mode
      • Difference between process and thread switching commands
      • Accessing Invalid Address
      • Transparent Mode
    • Nested-Virtualization Environments
      • Supported Virtual Machines
      • Run HyperDbg on VMware
      • Run HyperDbg on Hyper-V
      • Supporting VMware/Hyper-V
      • VMware backdoor I/O ports
    • Misc
      • Event forwarding
      • Event short-circuiting
      • Event calling stage
      • Instant events
      • Message overflow
      • Customize build
        • Increase Communication Buffer Size
        • Number of EPT Hooks in One Page
        • Change Script Engine Limitations
      • Enable and disable events in Debugger Mode
      • Switch to New Process Layout
  • Contribution
    • Style Guide
      • Coding style
      • Command style
      • Doxygen style
    • Logo & Artworks
  • Design
    • Features
      • VMM (Module)
        • Control over NMIs
        • VMX root-mode compatible message tracing
        • Design of !epthook
        • Design of !epthook2
        • Design of !monitor
        • Design of !syscall & !sysret
        • Design of !exception & !interrupt
    • Debugger Internals
      • Events
      • Conditions
      • Actions
      • Kernel Debugger
        • Design Perspective
        • Connection
  • Links
    • Twitter
    • Telegram
    • Discord
    • Matrix
    • Mastodon
    • YouTube
    • hwdbg (Chip Debugger)
    • Doxygen
    • Contribution
Powered by GitBook
On this page
  • Command
  • Syntax
  • Description
  • Parameters
  • Examples
  • IOCTL
  • Remarks
  • Requirements
  • Related
Edit on GitHub
  1. Commands
  2. Extension Commands

!u, !u64, !u2, !u32 (disassemble physical address)

Description of '!u, !u64, !u2 !u32' commands in HyperDbg.

Command

!u

!u64

!u2

!u32

Syntax

!u [Address (hex)] [l Length (hex)]

!u64 [Address (hex)] [l Length (hex)]

!u2 [Address (hex)] [l Length (hex)]

!u32 [Address (hex)] [l Length (hex)]

!u and !u64 disassembles as x64 while !u2 and !u32 adisassembles as x86. !u and !u64 are the same commands while !u2 and !u32 are the same.

Description

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

Parameters

[Address (hex)]

The physical address of where we want to start to disassemble its memory.

[l Length (hex)] (optional)

The length (byte) in hex format.

Process ID doesn't make sense in physical memory. If you specify pid, then it is ignored.

Examples

The following command is used when we want to disassemble the content of memory (x64) at 1000 with length of 0x50bytes.

HyperDbg> !u 1000 l 50
00000000`00001000 0B 00                               or eax, dword ptr ds:[rax]
00000000`00001002 00 00                               add byte ptr ds:[rax], al
00000000`00001004 00 00                               add byte ptr ds:[rax], al
00000000`00001006 00 00                               add byte ptr ds:[rax], al
00000000`00001008 00 00                               add byte ptr ds:[rax], al
00000000`0000100a 86 80 D3 10 02 00                   xchg byte ptr ds:[rax+0x210D3], al
00000000`00001010 00 06                               add byte ptr ds:[rsi], al
00000000`00001012 01 01                               add dword ptr ds:[rcx], eax
00000000`00001014 00 00                               add byte ptr ds:[rax], al
00000000`00001016 00 00                               add byte ptr ds:[rax], al
00000000`00001018 03 01                               add eax, dword ptr ds:[rcx]
00000000`0000101a 00 00                               add byte ptr ds:[rax], al
00000000`0000101c 00 00                               add byte ptr ds:[rax], al
00000000`0000101e 00 00                               add byte ptr ds:[rax], al
00000000`00001020 00 10                               add byte ptr ds:[rax], dl
00000000`00001022 FA                                  cli
00000000`00001023 39 00                               cmp dword ptr ds:[rax], eax
00000000`00001025 F8                                  clc

The following command is used when we want to disassemble the content of memory (x64) at @rax+@rbx with length of 0x50bytes.

Note that the result of @rax+@rbx is 0x1000 in this case.

HyperDbg> !u @rax+@rbx l 50
00000000`00001000 0B 00                               or eax, dword ptr ds:[rax]
00000000`00001002 00 00                               add byte ptr ds:[rax], al
00000000`00001004 00 00                               add byte ptr ds:[rax], al
00000000`00001006 00 00                               add byte ptr ds:[rax], al
00000000`00001008 00 00                               add byte ptr ds:[rax], al
00000000`0000100a 86 80 D3 10 02 00                   xchg byte ptr ds:[rax+0x210D3], al
00000000`00001010 00 06                               add byte ptr ds:[rsi], al
00000000`00001012 01 01                               add dword ptr ds:[rcx], eax
00000000`00001014 00 00                               add byte ptr ds:[rax], al
00000000`00001016 00 00                               add byte ptr ds:[rax], al
00000000`00001018 03 01                               add eax, dword ptr ds:[rcx]
00000000`0000101a 00 00                               add byte ptr ds:[rax], al
00000000`0000101c 00 00                               add byte ptr ds:[rax], al
00000000`0000101e 00 00                               add byte ptr ds:[rax], al
00000000`00001020 00 10                               add byte ptr ds:[rax], dl
00000000`00001022 FA                                  cli
00000000`00001023 39 00                               cmp dword ptr ds:[rax], eax
00000000`00001025 F8                                  clc

The following example shows the assembly content of memory (x64) at 1000.

HyperDbg> !u 1000
00000000`00001000 0B 00                               or eax, dword ptr ds:[rax]
00000000`00001002 00 00                               add byte ptr ds:[rax], al
00000000`00001004 00 00                               add byte ptr ds:[rax], al
00000000`00001006 00 00                               add byte ptr ds:[rax], al
00000000`00001008 00 00                               add byte ptr ds:[rax], al
00000000`0000100a 86 80 D3 10 02 00                   xchg byte ptr ds:[rax+0x210D3], al
00000000`00001010 00 06                               add byte ptr ds:[rsi], al
00000000`00001012 01 01                               add dword ptr ds:[rcx], eax
00000000`00001014 00 00                               add byte ptr ds:[rax], al
00000000`00001016 00 00                               add byte ptr ds:[rax], al
00000000`00001018 03 01                               add eax, dword ptr ds:[rcx]
00000000`0000101a 00 00                               add byte ptr ds:[rax], al
00000000`0000101c 00 00                               add byte ptr ds:[rax], al
00000000`0000101e 00 00                               add byte ptr ds:[rax], al
00000000`00001020 00 10                               add byte ptr ds:[rax], dl
00000000`00001022 FA                                  cli
00000000`00001023 39 00                               cmp dword ptr ds:[rax], eax
00000000`00001025 F8                                  clc

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.

In the debugger mode, HyperDbg uses the exact same structure, you should send the above structure over serial to the debuggee which is paused in vmx-root mode.

You should send the above structure with DEBUGGER_REMOTE_PACKET_REQUESTED_ACTION_ON_VMX_ROOT_READ_MEMORY as RequestedAction and DEBUGGER_REMOTE_PACKET_TYPE_DEBUGGER_TO_DEBUGGEE_EXECUTE_ON_VMX_ROOT as PacketType.

In return, the debuggee sends the above structure with the following type.

DEBUGGER_REMOTE_PACKET_REQUESTED_ACTION_DEBUGGEE_RESULT_OF_READING_MEMORY

The following function is responsible for sending reading memory in the debugger.

BOOLEAN KdSendReadMemoryPacketToDebuggee(PDEBUGGER_READ_MEMORY ReadMem);

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 in HyperDbg. For example, 'l10' is invalid, but 'l 10' is valid. (It's opposed to windbg).

Physical addresses are not validated in HyperDbg, which means if you access an invalid physical address, then the debuggee halts or crashes.

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

Requirements

None

Related

Previous!sb, !sd, !sq (search physical memory)Next!dt (display and map physical memory to structures)

Last updated 10 months ago

HyperDbg won't remove breakpoints previously set using the '' command if you're disassembling or reading the memory of a special physical address. However, for the virtual addresses, HyperDbg ignores breakpoints and shows the target location's real value.

HyperDbg uses as its core disassembler.

bp
Zydis
Zydis
u (disassemble virtual address)
a (assemble virtual address)
!a (assemble physical address)