Walter J. Savitch

32 papers A* 5A 2Journal 19Unranked 3
YearRankTypeTitle / Venue / Authors
2011 ch.
Computer Science, The Hardware, Software and Heart of It
Edward K. Blum, Walter J. Savitch
2001 A conf
SIGCSE
Nell B. Dale, Rick Mercer, Elliot B. Koffman, Walter J. Savitch
1995 J jnl
Ann. Math. Artif. Intell.
P. A. Bensch, Walter J. Savitch
1995 book
Data structures and other objects - Turbo Pascal edition.
Michael Main, Walter J. Savitch
1995 book
Problem solving with C++ - the object of programming.
Walter J. Savitch
1994 A conf
SIGCSE
John W. McCormick, Fintan Culwin, Nicholas J. DeLillo, Michael B. Feldman, Richard E. Pattis, Walter J. Savitch
1993 J jnl
Ann. Math. Artif. Intell.
Walter J. Savitch
1989 J jnl
Comput. Linguistics
Walter J. Savitch
1984 J jnl
J. Comput. Syst. Sci.
Walter J. Savitch, Patrick W. Dymond
1984 J jnl
Inf. Process. Lett.
Walter J. Savitch, Paul M. B. Vitányi
1983 J jnl
Math. Syst. Theory
Walter J. Savitch
1982 J jnl
Math. Syst. Theory
Walter J. Savitch
1981 J jnl
Fundam. Informaticae
Dirk Vermeir, Walter J. Savitch
1980 J jnl
Inf. Control.
Peter Eichhorst, Walter J. Savitch
1979 J jnl
Inf. Control.
Zdzislaw Pawlak, Grzegorz Rozenberg, Walter J. Savitch
1979 J jnl
J. ACM
Walter J. Savitch, Michael J. Stimson
1978 conf
Graph-Grammars and Their Application to Computer Science and Biology
Walter J. Savitch
1978 J jnl
J. Comput. Syst. Sci.
Paul M. B. Vitányi, Walter J. Savitch
1978 A* conf
ICALP
Walter J. Savitch
1978 A* ed.
STOC
Richard J. Lipton, Walter A. Burkhard, Walter J. Savitch, Emily P. Friedman, Alfred V. Aho
1977 A* conf
ICALP
Walter J. Savitch, Paul M. B. Vitányi
1975 J jnl
J. Comput. Syst. Sci.
Ann Reedy, Walter J. Savitch
1975 conf
Automata, Languages, Development
Walter J. Savitch
1975 conf
Automata, Languages, Development
Walter J. Savitch
1975 J jnl
Inf. Control.
Walter J. Savitch
1975 J jnl
Theor. Comput. Sci.
Ann Reedy, Walter J. Savitch
1973 J jnl
Acta Informatica
Walter J. Savitch
1973 J jnl
SIAM J. Comput.
Walter J. Savitch
1973 J jnl
J. Comput. Syst. Sci.
Walter J. Savitch
1972 A* conf
STOC
Walter J. Savitch
1970 J jnl
J. Comput. Syst. Sci.
Walter J. Savitch
1969 A* conf
STOC
Walter J. Savitch
redb/extractors/capa.py
← Index redb/extractors/capa.py python
from dataclasses import asdict
import inspect
import json
import subprocess
import magic
from magika import Magika
from typing import Any, Dict, List, Tuple
from datetime import datetime, timezone

from redb.extractors.enum import Tag
from redb.models.dataclasses import CAPA
from redb.extractors.extractor import Extractor
from dotenv import load_dotenv
import os

load_dotenv(override=True)

class CAPAExtractor(Extractor):

    def __init__(
        self,
        filepath,
        log,
        exporters=None,
        index_prefix=None,
        elastic_index=None,
        known_benign=False,
        known_malicious=False,
    ):
        super().__init__(
            filepath, 
            log, 
            exporters,
            index_prefix, 
            elastic_index, 
            known_benign, 
            known_malicious
        )
        self.capa = None
        self.elastic_index = self.index_prefix + "-capa"

    def _replace_empty_keys(self, dictionary, replacement="default_empty_key"):
        """
        Replace empty keys in a dictionary with a specified replacement.

        Args:
        dictionary (dict): The input dictionary
        replacement (str): The replacement for empty keys (default: 'empty_key')

        Returns:
        dict: A new dictionary with empty keys replaced
        """
        # tmp_dict = {}
        # for k, v in dictionary.items():
        #     if k == '':
        #         tmp_dict[replacement] = dictionary[k]
        #     else:
        #         tmp_dict[k] = dictionary[k]
        # return tmp_dict
        return {(replacement if k == "" else k): v for k, v in dictionary.items()}

    def _extract_capa(self):
        self.log.debug(inspect.currentframe().f_code.co_name)
        TIMEOUT = int(os.getenv("CAPA_TIMEOUT")) # 5 minutes in seconds
        capa_command = [os.getenv("CAPA_PATH"), "-j", self.filepath] # COMMENT FOR TESTING ON MAC

        import signal

        # try:
        #     result = subprocess.run(
        #         capa_command, capture_output=True, text=True, check=True, timeout=TIMEOUT
        #     )
        # except subprocess.TimeoutExpired:
        #     self.log.error(f"The capa command timed out after {TIMEOUT} seconds")
        #     return {}
        # except subprocess.CalledProcessError as e:
        #     self.log.error(f"Error running capa: {e}")
        #     return {}

        # try:
        #     capa_output = json.loads(result.stdout)
        # except json.JSONDecodeError as e:
        #     self.log.error("Error parsing capa output: {e}")
        #     return {}

        # Create a process group for easier termination of all child processes
        try:
            # Start the process in a new process group
            process = subprocess.Popen(
                capa_command,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
                text=True,
                preexec_fn=os.setsid  # Use os.setsid() to create a new process group
            )
            
            # Implement timeout handling manually
            try:
                stdout, stderr = process.communicate(timeout=TIMEOUT)
                # Process completed within timeout
                if process.returncode != 0:
                    self.log.error(f"Error running capa, return code: {process.returncode}, stderr: {stderr}")
                    return {}
            except subprocess.TimeoutExpired:
                # Kill the entire process group on timeout
                self.log.warning(f"The capa command timed out after {TIMEOUT} seconds, terminating process group")
                
                try:
                    # Send SIGTERM to the entire process group
                    os.killpg(process.pid, signal.SIGTERM)
                    
                    # Give it a moment to terminate gracefully
                    try:
                        process.wait(timeout=3)
                    except subprocess.TimeoutExpired:
                        # If it's still running after 3 seconds, send SIGKILL
                        self.log.warning("Process didn't terminate with SIGTERM, sending SIGKILL")
                        os.killpg(process.pid, signal.SIGKILL)
                        
                    process.wait()  # Make sure process resources are fully cleaned up
                except (ProcessLookupError, OSError) as e:
                    self.log.warning(f"Error while killing process: {e}")
                    
                return {}
                
            try:
                capa_output = json.loads(stdout)
            except json.JSONDecodeError as e:
                self.log.error(f"Error parsing capa output: {e}")
                return {}

            capa_dump = {}  # dictionalry of capabilities
            capabilities = set()  # list of capabilities
            namespaces = set()  # list of namespaces
            attack_dump = {}  # dictionary of tuples [tactic](technique, technique_id)
            tactics = set()  # list of tactics
            techniques = set()  # list of techniques
            techniques_id = set()  # list of techniques_id
            mbc_dump = {}  # dictionary of tuples [objective](behavior, behavior_id)
            mbc_objectives = set()  # list of objectives
            mbc_behaviors = set()  # list of behaviors
            mbc_behaviors_id = set()  # list of behaviors_id

            if isinstance(capa_output, dict) and "rules" in capa_output:
                rules = capa_output["rules"]
                if isinstance(rules, dict):
                    for rule_name, rule_data in rules.items():
                        if isinstance(rule_data, dict) and "meta" in rule_data:
                            meta = rule_data["meta"]
                            if isinstance(meta, dict):
                                # Process capabilities
                                namespace = meta.get("namespace", "").lower()
                                # if namespace != 'lib':
                                if namespace not in capa_dump:
                                    capa_dump[namespace] = []
                                    namespaces.add(namespace)
                                capa_dump[namespace].append(rule_name)
                                capabilities.add(rule_name)

                                # Process ATTACK information
                                if "attack" in meta:
                                    for attack_entry in meta["attack"]:
                                        tactic = attack_entry.get("tactic", "")
                                        technique = attack_entry.get("technique", "")
                                        id = attack_entry.get("id", "")
                                        if tactic and technique:
                                            if tactic in attack_dump:
                                                attack_dump[tactic].append((technique, id))
                                            else:
                                                attack_dump[tactic] = [(technique, id)]
                                            tactics.add(tactic)
                                            techniques.add(technique)
                                            techniques_id.add(id)

                                # Process MBC information
                                if "mbc" in meta:
                                    for mbc_entry in meta["mbc"]:
                                        objective = mbc_entry.get("objective", "")
                                        behavior = mbc_entry.get("behavior", "")
                                        id = mbc_entry.get("id", "")
                                        if objective and behavior:
                                            if objective in mbc_dump:
                                                mbc_dump[objective].append((behavior, id))
                                            else:
                                                mbc_dump[objective] = [(behavior, id)]
                                            mbc_objectives.add(objective)
                                            mbc_behaviors.add(behavior)
                                            mbc_behaviors_id.add(id)

            # return {
            #     'capabilities_all': json.dumps(capabilities_all, indent=2),
            #     'capabilities': list(capabilities),
            #     'namespaces': list(namespaces),
            #     'attack': json.dumps(attack, indent=2),
            #     'tactics': list(tactics),
            #     'techniques': list(techniques),
            #     'techniques_id': list(techniques_id),
            #     'mbc': json.dumps(mbc, indent=2),
            #     'mbc_objectives': list(mbc_objectives),
            #     'mbc_behaviors': list(mbc_behaviors),
            #     'mbc_behaviors_id': list(mbc_behaviors_id)
            # }

            capa_dump = self._replace_empty_keys(capa_dump)
            attack_dump = self._replace_empty_keys(attack_dump)
            mbc_dump = self._replace_empty_keys(mbc_dump)
            self.capa = CAPA(
                json.dumps(capa_dump, indent=2),
                list(capabilities),
                list(namespaces),
                json.dumps(attack_dump, indent=2),
                list(tactics),
                list(techniques),
                list(techniques_id),
                json.dumps(mbc_dump, indent=2),
                list(mbc_objectives),
                list(mbc_behaviors),
                list(mbc_behaviors_id),
            )
            self.log.debug(f"CAPA dump: {self.capa})")
            
        except Exception as e:
            self.log.error(f"Unexpected error in CAPA extraction: {str(e)}")
            # Try to clean up any process if possible
            if 'process' in locals() and process.poll() is None:
                try:
                    os.killpg(process.pid, signal.SIGKILL)
                    process.wait()
                except:
                    pass
            return {}

    def prepare_export_data(self, exporter_type: str) -> Any:
        if exporter_type == "ElasticsearchExporter":
            return self.capa
        elif exporter_type == "ClickHouseExporter":
            current_time = datetime.now(timezone.utc)
            
            # Prepare data for multiple tables
            tables_data = {
                'multi_table': True,  # Flag for multi-table export
                
                # Raw data table
                'raw': {
                    'table': 'redb_capa',
                    'data': [[
                        self.sha256,
                        self.md5,
                        self.sha1,
                        current_time,
                        self.capa.capa_dump,  # capa_dump
                        self.capa.attack_dump,            # attack_dump
                        self.capa.mbc_dump                # mbc_dump
                    ]],
                    'column_names': [
                        'sha256', 'md5', 'sha1', 'analysis_date',
                        'capa_dump', 'attack_dump', 'mbc_dump'
                    ],
                    'column_type_names': [
                        'FixedString(64)', 'FixedString(32)', 'FixedString(40)',
                        'DateTime64(3, \'UTC\')',
                        'JSON', 'JSON', 'JSON'
                    ]
                },
                
                # Capabilities table
                'capabilities': {
                    'table': 'redb_capa_capabilities',
                    'data': [
                        [self.sha256, self.md5, self.sha1, current_time, namespace, capability]
                        for namespace, capabilities in json.loads(self.capa.capa_dump).items()
                        for capability in capabilities
                    ],
                    'column_names': [
                        'sha256', 'md5', 'sha1', 'analysis_date',
                        'namespace', 'capability'
                    ],
                    'column_type_names': [
                        'FixedString(64)', 'FixedString(32)', 'FixedString(40)',
                        'DateTime64(3, \'UTC\')',
                        'LowCardinality(String)', 'LowCardinality(String)'
                    ]
                },
                
                # MITRE ATT&CK table
                'attack': {
                    'table': 'redb_capa_attack',
                    'data': [
                        [self.sha256, self.md5, self.sha1, current_time, 
                         tactic, technique[0], technique[1]]  # technique[0] is the name, technique[1] is the ID
                        for tactic, techniques in json.loads(self.capa.attack_dump).items()
                        for technique in techniques
                    ],
                    'column_names': [
                        'sha256', 'md5', 'sha1', 'analysis_date',
                        'tactic', 'technique', 'technique_id'
                    ],
                    'column_type_names': [
                        'FixedString(64)', 'FixedString(32)', 'FixedString(40)',
                        'DateTime64(3, \'UTC\')',
                        'LowCardinality(String)', 'LowCardinality(String)', 
                        'LowCardinality(String)'
                    ]
                },
                
                # MBC table
                'mbc': {
                    'table': 'redb_capa_mbc',
                    'data': [
                        [self.sha256, self.md5, self.sha1, current_time,
                         objective, behavior[0], behavior[1]]  # behavior[0] is the name, behavior[1] is the ID
                        for objective, behaviors in json.loads(self.capa.mbc_dump).items()
                        for behavior in behaviors
                    ],
                    'column_names': [
                        'sha256', 'md5', 'sha1', 'analysis_date',
                        'objective', 'behavior', 'behavior_id'
                    ],
                    'column_type_names': [
                        'FixedString(64)', 'FixedString(32)', 'FixedString(40)',
                        'DateTime64(3, \'UTC\')',
                        'LowCardinality(String)', 'LowCardinality(String)',
                        'LowCardinality(String)'
                    ]
                }
            }
            
            return tables_data

    def get_clickhouse_table(self) -> str:
        return "redb_capa"  # Return the main table name

    def extract(self):
        self.log.debug(inspect.currentframe().f_code.co_name)
        try:
            self._extract_capa()
            return self.capa  # Return the extracted data instead of exporting directly
        except Exception as e:
            self.log.error(f"Error extracting CAPA: {e}")
            return None

    def tag(self):
        return Tag.CAPA.value