Below is the old README file for this library.

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memoryjs ·

memoryjs is an NPM package for reading and writing process memory! (finally!)

NOTE: version 3 of this library introduces breaking changes that are incompatible with previous versions. The notable change is that when reading memory, writing memory and pattern scanning you are required to pass the handle through for the process (that is returned from memoryjs.openProcess). This allows for multi-process support.

Features

• open a process
• close the process (handle)
• list all open processes
• list all modules associated with a process
• find a certain module associated with a process
• read memory
• write to memory
• read/write buffers
• change memory protection
• reserve/allocate, commit or change regions of memory
• pattern scanning
• execute a function

TODO:

• WriteFile support (for driver interactions)
• DLL injections

Install

This is a Node add-on (last tested to be working on v8.11.3) and therefore requires node-gyp to use.

You may also need to follow these steps.

npm install memoryjs

When using memoryjs, the target process should match the platform architecture of the Node version running. For example if you want to target a 64 bit process, you should try and use a 64 bit version of Node.

You also need to recompile the library and target the platform you want. Head to the memoryjs node module directory, open up a terminal and to run the compile scripts, type:

npm run build32 if you want to target 32 bit processes

npm run build64 if you want to target 64 bit processes

Node Webkit / Electron

If you are planning to use this module with Node Webkit or Electron, take a look at Liam Mitchell's build notes here.

Usage

Initialise:

const memoryjs = require('memoryjs');
const processName = "csgo.exe";

Processes:

Open a process (sync):

const processObject = memoryjs.openProcess(processIdentifier);

Open a process (async):

memoryjs.openProcess(processIdentifier, (error, processObject) => {

});

Get all processes (sync):

const processes = memoryjs.getProcesses();

Get all processes (async):

memoryjs.getProcesses((error, processes) => {

});

See the Documentation section of this README to see what a process object looks like.

Modules:

Find a module (sync):

const module = memoryjs.findModule(moduleName, processId);

Find a module (async):

memoryjs.findModule(moduleName, processId, (error, module) => {

});

Get all modules (sync):

const modules = memoryjs.getModules(processId);

Get all modules (async):

memoryjs.getModules(processId, (error, modules) => {

});

See the Documentation section of this README to see what a module object looks like.

Memory:

Read from memory (sync):

const value = memoryjs.readMemory(handle, address, dataType);

Read from memory (async):

memoryjs.readMemory(handle, address, dataType, (error, value) => {

});

Read buffer from memory (sync):

const buffer = memoryjs.readBuffer(handle, address, size);

Read buffer from memory (async):

memoryjs.readBuffer(handle, address, size, (error, buffer) => {

});

Write to memory:

memoryjs.writeMemory(handle, address, value, dataType);

Write buffer to memory:

memoryjs.writeBuffer(handle, address, buffer);

See the Documentation section of this README to see what values dataType can be.

Protection:

Set protection of memory:

const oldProtection = memoryjs.setProtection(handle, address, size, protection);

See the Documentation section of this README to see what values protection can be.

Pattern Scanning:

Pattern scanning (sync):

const offset = memoryjs.findPattern(handle, moduleName, signature, signatureType, patternOffset, addressOffset);

Pattern scanning (async):

memoryjs.findPattern(handle, moduleName, signature, signatureType, patternOffset, addressOffset, (error, offset) => {

})

Function Execution:

Function execution (sync):

const result = memoryjs.callFunction(handle, args, returnType, address);

Function execution (async):

memoryjs.callFunction(handle, args, returnType, address, (error, result) => {

});

Click here to see what a result object looks like. Clicklick here for details about how to format the arguments and the return type.

Documentation

Process Object:

{ dwSize: 304,
  th32ProcessID: 10316,
  cntThreads: 47,
  th32ParentProcessID: 7804,
  pcPriClassBase: 8,
  szExeFile: "csgo.exe",
  modBaseAddr: 1673789440,
  handle: 808 }

The handle and modBaseAddr properties are only available when opening a process and not when listing processes.

Module Object:

{ modBaseAddr: 468123648,
  modBaseSize: 80302080,
  szExePath: 'c:\\program files (x86)\\steam\\steamapps\\common\\counter-strike global offensive\\csgo\\bin\\client.dll',
  szModule: 'client.dll',
  th32ProcessID: 10316 }

Result Object:

{ returnValue: 1.23,
  exitCode: 2 }

The returnValue is the value returned from the function that was called. exitCode is the termination status of the thread.

Data Type:

When using the write or read functions, the data type (dataType) parameter can either be a string and be one of the following:

"byte", "int", "int32", "uint32", "int64", "uint64", "dword", "short", "long", "float", "double", "bool", "boolean", "ptr", "pointer", "str", "string", "vec3", "vector3", "vec4", "vector4"

or can reference constants from within the library:

memoryjs.BYTE, memoryjs.INT, memoryjs.INT32, memoryjs.UINT32, memoryjs.INT64, memoryjs.UINT64, memoryjs.DWORD, memoryjs.SHORT, memoryjs.LONG, memoryjs.FLOAT, memoryjs.DOUBLE, memoryjs.BOOL, memoryjs.BOOLEAN, memoryjs.PTR, memoryjs.POINTER, memoryjs.STR, memoryjs.STRING, memoryjs.VEC3, memoryjs.VECTOR3, memoryjs.VEC4, memoryjs.VECTOR4

This is simply used to denote the type of data being read or written.

Vector3 is a data structure of three floats:

const vector3 = { x: 0.0, y: 0.0, z: 0.0 };
memoryjs.writeMemory(address, vector3);

Vector4 is a data structure of four floats:

const vector4 = { w: 0.0, x: 0.0, y: 0.0, z: 0.0 };
memoryjs.writeMemory(address, vector4);

Generic Structures:

If you have a structure you want to write to memory, you can use buffers. For an example on how to do this, view the buffers example.

To write a structure to memory, you can use the concentrate library to describe the structure as a buffer and then write the buffer to memory using the writeBuffer function.

To read a structure from memory, you will need to read a buffer from memory using the readBuffer function, and then you can use the dissolve library to parse the buffer into a structure.

In either case you don't need to use the two libraries mentioned above, they just make it easy to turn your structure into a buffer, and your buffer into a structure.

Protection Type:

Protection type is a bit flag DWORD value.

This parameter should reference a constant from the library:

memoryjs.PAGE_NOACCESS, memoryjs.PAGE_READONLY, memoryjs.PAGE_READWRITE, memoryjs.PAGE_WRITECOPY, memoryjs.PAGE_EXECUTE, memoryjs.PAGE_EXECUTE_READ, memoryjs.PAGE_EXECUTE_READWRITE, memoryjs.PAGE_EXECUTE_WRITECOPY, memoryjs.PAGE_GUARD, memoryjs.PAGE_NOCACHE, memoryjs.PAGE_WRITECOMBINE, memoryjs.PAGE_ENCLAVE_THREAD_CONTROL, memoryjs.PAGE_TARGETS_NO_UPDATE, memoryjs.PAGE_TARGETS_INVALID, memoryjs.PAGE_ENCLAVE_UNVALIDATED

Refer to MSDN's Memory Protection Constants for more information.

Memory Allocation Type:

Memory allocation type is a bit flag DWORD value.

This parameter should reference a constat from the library:

memoryjs.MEM_COMMIT, memoryjs.MEM_RESERVE, memoryjs.MEM_RESET, memoryjs.MEM_RESET_UNDO

Refer to MSDN's VirtualAllocEx documentation for more information.

Strings:

You can use this library to read either a "string", or "char*" and to write a string.

In both cases you want to get the address of the char array:

std::string str1 = "hello";
std::cout << "Address: 0x" << hex << (DWORD) str1.c_str() << dec << std::endl;

char* str2 = "hello";
std::cout << "Address: 0x" << hex << (DWORD) str2 << dec << std::endl;

From here you can simply use this address to write and read memory.

There is one caveat when reading a string in memory however, due to the fact that the library does not know how long the string is, it will continue reading until it finds the first null-terminator. To prevent an infinite loop, it will stop reading if it has not found a null-terminator after 1 million characters.

One way to bypass this limitation in the future would be to allow a parameter to let users set the maximum character count.

Signature Type:

When pattern scanning, flags need to be raised for the signature types. The signature type parameter needs to be one of the following:

0x0 or memoryjs.NORMAL which denotes a normal signature.

0x1 or memoryjs.READ which will read the memory at the address.

0x2 or memoryjs.SUBSTRACT which will subtract the image base from the address.

To raise multiple flags, use the bitwise OR operator: memoryjs.READ | memoryjs.SUBTRACT.

Function Execution:

Remote function execution works by building an array of arguments and dynamically generating shellcode that is injected into the target process and executed, for this reason crashes may occur.

To call a function in a process, the callFunction function can be used. The library supports passing arguments to the function and need to be in the following format:

[{ type: T_INT, value: 4 }]

The library expects the arguments to be an array of objects where each object has a type which denotes the data type of the argument, and a value which is the actual value of the argument. The various supported data types can be found below.

memoryjs.T_VOID = 0x0,
memoryjs.T_STRING = 0x1,
memoryjs.T_CHAR = 0x2,
memoryjs.T_BOOL = 0x3,
memoryjs.T_INT = 0x4,
memoryjs.T_DOUBLE = 0x5,
memoryjs.T_FLOAT = 0x6,

When using callFunction, you also need to supply the return type of the function, which again needs to be one of the above values.

For example, given the following C++ function:

int add(int a, int b) {
    return a + b;
}

You would call this function as so:

const args = [{
    type: memoryjs.T_INT,
    value: 2,
}, {
    type: memoryjs.T_INT,
    value: 5,
}];
const returnType = T_INT;

> memoryjs.callFunction(handle, args, returnType, address);
{ returnValue: 7, exitCode: 7 }

See the result object documentation for details on what callFunction returns.

Notes: currently passing a double as an argument is not supported, but returning one is.

Much thanks to the various contributors that made this feature possible.

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openProcess(processIdentifier[, callback])

opens a process to be able to read from and write to it

• processIdentifier (string/int) - the identifier of the process to open, can either be a name ('csgo.exe') or an id (3270)
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • processObject (object) - information about the process

returns process object (object) either directly or via the callback

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closeProcess(handle)

closes the handle on the opened process

• handle (int) - the handle of the process to close

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getProcesses([callback])

collects information about all the running processes

• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • processes (array) - array of process object (JSON)

returns an array of process object (object) for all the running processes

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findModule(moduleName, processId[, callback])

finds a module associated with a given process

• moduleName (string) - the name of the module to find
• processId (int) - the id of the process in which to find the module
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • module (object) - information about the module

returns module object (object) either directly or via the callback

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getModules(processId[, callback])

gets all modules associated with a given process

• processId (int) - the id of the process in which to find the module
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • modules (array) - array of module object (JSON)

returns an array of module object (object) for all the modules found

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readMemory(handle, address, dataType[, callback])

reads the memory at a given address

• handle (int) - the handle of the process, given to you by the process object retrieved when opening the process
• address (int) - the address in memory to read from
• dataType (string) - the data type to read into (definitions can be found at the top of this section)
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • value (any data type) - the value stored at the given address in memory

returns the value that has been read from memory

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readBuffer(handle, address, size[, callback])

reads size bytes of memory at the given address

• handle (int) - the handle of the process, given to you by the process object retrieved when opening the process
• address (int) - the address in memory to read from
• size (int) - the number of bytes to read into the buffer
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • value (buffer) - the bytes read from memory at the given address in a buffer

returns the bytes read from memory at the given address in a buffer

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writeMemory(handle, address, value, dataType[, callback])

writes to an address in memory

• handle (int) - the handle of the process, given to you by the process object retrieved when opening the process
• address (int) - the address in memory to write to
• value (any data type) - the data type of value must be either number, string or boolean and is the value that will be written to the address in memory
• dataType (string) the data type of the value (definitions can be found at the top of this section)
• callback (function) - has one parameter:
  • err (string) - error message (empty if there were no errors)

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writeBuffer(handle, address, buffer)

writes size bytes of memory to the given address

• handle (int) - the handle of the process, given to you by the process object retrieved when opening the process
• address (int) - the address in memory to write to
• buffer (buffer) - the buffer to write to memory

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findPattern(handle, moduleName, signature, signatureType, patternOffset, addressOffset[, callback])

pattern scans memory to find an offset

• handle (int) - the handle of the process, given to you by the process object retrieved when opening the process
• moduleName (string) - the name of the module to pattern scan (module.szModule)
• signature (string) - the actual signature mask (in the form A9 ? ? ? A3 ?)
• signatureType (int) - flags for signature types (definitions can be found at the top of this section)
• patternOffset (int) - offset will be added to the address (before reading, if memoryjs.READ is raised)
• addressOffset (int) - offset will be added to the address returned
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • offset (int) - value of the offset found (will return -1 if the module was not found, -2 if the pattern found no address)

returns the value of the offset found

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setProtection(handle, address, size, protection)

sets the protection of the memory address

• handle (int) - the handle of the process, given to you by the process object retrieved when opening the process
• address (int) - the address in memory to write to
• size (int) - number of bytes at the address to change the protection of
• protection (int) the protection type to set this if a bit flag

returns old protection value

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callFunction(handle, args, returnType, address[, callback])

calls a function at the given address with the given arguments

• handle (int) - the handle of the process in which the function lies
• args (array of objects) - the arguments being supplied to the function
• returnType (int) - the return type of the function
• address (int) - the absolute of the address of the function
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • result (object) - result of the function call

returns result object (object) either directly or via the callback

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virtualAllocEx(handle, address, size, allocationType, protection[, callback])

reserves, commits or changes the state of a region of memory within the virtual address space of a specified process

• handle (int) - the handle of the process in which the memory region whose state you want to change lies
• address (int) - the starting address for the region you want to allocate, leave this argument as null if you want the function to determine where to allocate the memory region
• size (int) - the size of the region of memory to allocate
• allocationType (int) - the type of memory allocation, choose from one of the allocation types
• protection (int) - the memory protection for the region of pages to be allocated, specify one of the protection types
• callback (function) - has two parameters:
  • err (string) - error message (empty if there were no errors)
  • result (number) - base address of the allocated region of pages if successful

returns base address of the allocated region of pages if successful.

Notes: please refer to the VirtualAllocEx documentation for more details. If this function fails and no callback was passed, an error will be thrown. If you want to allocate memory, leave the address argument as null.