HyperDbg Documentation
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  • 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
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On this page
  • Conditional Statements
  • if
  • else
  • elsif
  • Loops
  • for
  • while
  • do, while
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  1. Commands
  2. Scripting Language

Conditionals & Loops

Description of conditional statements and loops

Conditional Statements

Conditional statements are used to perform different actions based on different conditions.

if

The if statement executes some code if one condition is true.

Syntax

if (condition) {
  code to be executed if condition is true;
}

Example 1

if (@rax == 55) {
    printf("rax is equal to %llx\n", @rax);
}

Example 2

if (poi(@rcx + 0x10) == ffff7080deadbeef && @rdx != 55 || $pid == 4) {
    printf("condition is met\n");
}

else

The else statement is executed if the if condition is false.

Syntax

if (condition) {
  code to be executed if condition is true;
}
else {
  if the above condition is false, then else is called;
}

Example

if (@rax == 55) {
    printf("rax is equal to %llx\n", @rax);
}
else {
    printf("rax is not equal to 0x55, it is equal to %llx\n", @rax);
}

elsif

Multiple if...else statements can be nested to create an elsif clause. Note that there is one elsif (in one word) keyword in HyperDbg script engine.

Syntax

if (condition) {
  code to be executed if condition is true;
}
elsif (condition) {
  code to be executed if elsif condition is true;
}
else {
  if none of the above conditions are true, then else is called;
}

Example

if (@rax == 55) {
    printf("rax is equal to 0x55\n");
}
elsif (@rax == 66) {
    printf("rax is equal to 0x66\n");
}
elsif (@rax == 77) {
    printf("rax is equal to 0x77\n");
}
else {
    printf("rax is not equal to 0x55, 0x66, 0x77. It is equal to %llx\n", @rax);
}

Loops

The following statements are used to create loops in HyperDbg's script engine.

for

The for statement creates a loop that consists of three expressions, enclosed in parentheses and separated by semicolons, followed by a block statement to be executed in the loop.

Syntax

for (initial value; condition; incrementation or decrementation) {
  code to be executed in loop;
}

Example 1

for (i = 10; i != 0; i--) { 
    printf("%d\n", i); 
}

Example 2

for (i = 0; i < 10 ; i++) {
    for (j = 0; j < 10; j++) {
        printf("%d, %d\n", i, j); 
   }
 }

while

With the while loop, we can execute a set of statements as long as the condition is true.

Syntax

while (condition) {
  code to be executed if while condition is true;
}

Example

x = 55;
while (x) {
    printf("x = %x\n", x);
    x = x - 1;
}

do, while

The do..while loop is similar to the while loop with one important difference. The body of do...while loop is executed at least once. Only then, the test expression is evaluated.

Syntax

do {
  code to be executed at least one time and continues,
   if while condition is true;
}
while (condition); 

Example

x = 55;
do {
    printf("x = %x\n", x);
    x = x - 1;
} while (x);
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Last updated 1 year ago