db, dc, dd, dq (read virtual memory)

Description of 'db, dc, dd, dq' commands in HyperDbg.

Command

db : read memory as Byte values and ASCII characters

dc : read memory as Double-word values (4 bytes) and ASCII characters

dd : read memory as Double-word values (4 bytes)

dq : read memory as Quad-word values (8 bytes)

Syntax

db [Address (hex)] [l Length (hex)] [pid ProcessId (hex)]

dc [Address (hex)] [l Length (hex)] [pid ProcessId (hex)]

dd [Address (hex)] [l Length (hex)] [pid ProcessId (hex)]

dq [Address (hex)] [l Length (hex)] [pid ProcessId (hex)]

Description

Shows the virtual address memory content in hex form.

Parameters

[Address (hex)]

The virtual address of where we want to read its memory.

[l Length (hex)] (optional)

The length (byte) in hex format.

[pid ProcessId (hex)] (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.

In the Debugger Mode, the pid (parameter) is ignored. If you want to view another process memory, use the '.process' command to switch to another process memory layout.

Examples

The following command is used when we want to read the content of memory at nt!Kd_DEFAULT_Mask with length of 0x50from the memory layout view of process (4 a.k.a. system process) in a hex byte format.

HyperDbg> db Kd_DEFAULT_Mask l 50 pid 4
fffff801`63cf49ec  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
fffff801`63cf49fc  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
fffff801`63cf4a0c  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
fffff801`63cf4a1c  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
fffff801`63cf4a2c  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................

The following command is used when we want to read the content of memory at nt!Kd_DEFAULT_Mask+@rax+10 with length of 0x30from the memory layout view of process (4 a.k.a. system process) in a hex byte format.

Note that @rax is 0x10 in this case.

HyperDbg> db Kd_DEFAULT_Mask+@rax+10 l 30 pid 4
fffff801`63cf4a0c  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
fffff801`63cf4a1c  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
fffff801`63cf4a2c  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................

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

HyperDbg> db fffff800`3ad6f010 l 50 pid 4
fffff800`3ad6f010  48 89 5C 24 08 48 89 6C 24 10 48 89 74 24 18 57  H.\$.H.l$.H.t$.W
fffff800`3ad6f020  41 56 41 57 48 83 EC 30 65 48 8B 04 25 20 00 00  AVAWH..0eH.. ..
fffff800`3ad6f030  00 33 DB 44 0F B7 3D C5 3F 20 00 41 8B E8 48 8B  .3.D..=.? .A..H.
fffff800`3ad6f040  F2 89 5C 24 68 8B F9 4C 8B 88 C0 00 00 00 45 0F  ..\$h..L......E.
fffff800`3ad6f050  B7 B1 92 00 00 00 41 8B C6 44 8B C8 89 5C 24 20  ......A..D...\$

The following example shows the content of memory at fffff800`3ad6f010 from current process layout in a Double-word value (4 bytes) and ASCII characters format.

HyperDbg> dc fffff800`3ad6f010
fffff800`3ad6f010  245C8948 6C894808 89481024 57182474  H.\$.H.l$.H.t$.W
fffff800`3ad6f020  57415641 30EC8348 048B4865 00002025  AVAWH..0eH.. ..
fffff800`3ad6f030  44DB3300 C53DB70F 4100203F 8B48E88B  .3.D..=.? .A..H.
fffff800`3ad6f040  245C89F2 4CF98B68 00C0888B 0F450000  ..\$h..L......E.
fffff800`3ad6f050  0092B1B7 8B410000 C88B44C6 20245C89  ......A..D...\$
fffff800`3ad6f060  48C58B44 CF8BD68B CC3693E8 C08548FF  D..H......6..H..
fffff800`3ad6f070  0038840F 8B480000 6C8B48D8 8B485824  ..8...H..H.l$XH.
fffff800`3ad6f080  5C8B48C3 8B485024 48602474 4130C483  .H.\$PH.t$`H..0A

The following example shows the content of memory at fffff800`3ad6f010 from current process layout in a Double-word values (4 bytes) format with the length of 0x10.

HyperDbg> dd fffff800`3ad6f010 l 10
fffff800`3ad6f010  245C8948 6C894808 89481024 57182474

The following example shows the content of memory at fffff800`3ad6f010 from current process layout in a Quad-word values (8 bytes) format.

0: kHyperDbg> dq fffff800`3ad6f010
fffff800`3ad6f010  6C894808`245C8948 57182474`89481024
fffff800`3ad6f020  30EC8348`57415641 00002025`048B4865
fffff800`3ad6f030  C53DB70F`44DB3300 8B48E88B`4100203F
fffff800`3ad6f040  4CF98B68`245C89F2 0F450000`00C0888B
fffff800`3ad6f050  8B410000`0092B1B7 20245C89`C88B44C6
fffff800`3ad6f060  CF8BD68B`48C58B44 C08548FF`CC3693E8
fffff800`3ad6f070  8B480000`0038840F 8B485824`6C8B48D8
fffff800`3ad6f080  8B485024`5C8B48C3 4130C483`48602474

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(s) 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_DISASSEMBLE, 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_DISASSEMBLE as the Style.

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 0x80 Bytes.

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

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

Requirements

None

Related

!db, !dc, !dd, !dq (read physical memory)