James Alfred Walker

85 papers A 7B 11C 12Misc 1Journal 26Unranked 22
YearRankTypeTitle / Venue / Authors
2025 conf
ACL (4)
Hosein Rezaei, James Alfred Walker, Frank Soboczenski
2024 C conf
IMX
Alan Pedrassoli Chitayat, Florian Block, James Alfred Walker, Anders Drachen
2024 C conf
IMX
Alan Pedrassoli Chitayat, Alistair Coates, Florian Block, Anders Drachen, James Alfred Walker, James Dean, Mark Mcconachie, Peter York
2024 J jnl
Proc. ACM Hum. Comput. Interact.
Alan Pedrassoli Chitayat, Florian Block, James Alfred Walker, Anders Drachen
2024 B conf
ICTAI
Felix Ulrich-Oltean, Peter Nightingale, James Alfred Walker
2023 conf
AIIDE
Alan Pedrassoli Chitayat, Florian Block, James Alfred Walker, Anders Drachen
2023 J jnl
CoRR
Alan Pedrassoli Chitayat, Florian Block, James Alfred Walker, Anders Drachen
2023 J jnl
CoRR
Kevin Denamganaï, Daniel Hernández, Ozan Vardal, Sondess Missaoui, James Alfred Walker
2023 J jnl
CoRR
Felix Ulrich-Oltean, Peter Nightingale, James Alfred Walker
2023 J jnl
Constraints An Int. J.
Felix Ulrich-Oltean, Peter Nightingale, James Alfred Walker
2023 J jnl
CoRR
Kevin Denamganaï, Sondess Missaoui, James Alfred Walker
2022 J jnl
IEEE Trans. Games
Daniel Hernández, Kevin Denamganaï, Sam Devlin, Spyridon Samothrakis, James Alfred Walker
2022 C conf
FDG
Mark Ferguson, Sam Devlin, Daniel Kudenko, James Alfred Walker
2022 J jnl
Int. J. Child Comput. Interact.
Jennifer Chubb, Sondess Missaoui, Shauna Concannon, Liam Maloney, James Alfred Walker
2022 J jnl
CoRR
Kevin Denamganaï, Sondess Missaoui, James Alfred Walker
2022 A conf
CP
Felix Ulrich-Oltean, Peter Nightingale, James Alfred Walker
2021 J jnl
CoRR
Jennifer Chubb, Sondess Missaoui, Shauna Concannon, Liam Maloney, James Alfred Walker
2021 C conf
ALIFE
Adam Katona, Daniel W. Franks, James Alfred Walker
2021 J jnl
CoRR
Adam Katona, Daniel W. Franks, James Alfred Walker
2021 B conf
EvoApplications
Adam Katona, Nuno Lourenço, Penousal Machado, Daniel W. Franks, James Alfred Walker
2020 J jnl
CoRR
Daniel Hernández, Kevin Denamganaï, Sam Devlin, Spyridon Samothrakis, James Alfred Walker
2020 C conf
ICCC
Mark Ferguson, Sebastian Deterding, Andreas Lieberoth, Marc Malmdorf Andersen, Sam Devlin, Daniel Kudenko, James Alfred Walker
2020 C conf
CoG
Daniel Hernández, Charles Takashi Toyin Gbadamosi, James Goodman, James Alfred Walker
2020 J jnl
CoRR
Daniel Hernández, Charles Takashi Toyin Gbadamosi, James Goodman, James Alfred Walker
2020 conf
ACSW
Ryan J. Spick, Simon Demediuk, James Alfred Walker
2020 J jnl
CoRR
Kevin Denamganaï, James Alfred Walker
2020 C conf
FDG
Mark Ferguson, Sam Devlin, Daniel Kudenko, James Alfred Walker
2020 J jnl
CoRR
Kevin Denamganaï, James Alfred Walker
2020 conf
AIIDE
Charles Ringer, Mihalis A. Nicolaou, James Alfred Walker
2019 C conf
CoG
Daniel Hernández, Kevin Denamganaï, Alex Yuan Gao, Peter York, Sam Devlin, Spyridon Samothrakis, James Alfred Walker
2019 Misc conf
CHI PLAY
Oliver James Scholten, Nathan Gerard Jayy Hughes, Sebastian Deterding, Anders Drachen, James Alfred Walker, David Zendle
2019 J jnl
IET Comput. Digit. Tech.
Yuan Wang, Martin A. Trefzer, Simon J. Bale, James Alfred Walker, Andy M. Tyrrell
2019 C conf
CoG
Charles Ringer, James Alfred Walker, Mihalis A. Nicolaou
2019 J jnl
CoRR
Charles Ringer, James Alfred Walker, Mihalis A. Nicolaou
2019 C conf
CoG
Ryan J. Spick, Peter I. Cowling, James Alfred Walker
2019 conf
AIIDE
Simon Demediuk, Peter York, Anders Drachen, James Alfred Walker, Florian Block
2019 C conf
CoG
Adam Katona, Ryan J. Spick, Victoria J. Hodge, Simon Demediuk, Florian Block, Anders Drachen, James Alfred Walker
2019 J jnl
CoRR
Adam Katona, Ryan J. Spick, Victoria J. Hodge, Simon Demediuk, Florian Block, Anders Drachen, James Alfred Walker
2019 C conf
CoG
Oliver James Scholten, Peter I. Cowling, Kenneth A. Hawick, James Alfred Walker
2018 conf
DARE@PKDD/ECML
Ryan J. Spick, James Alfred Walker
2018 J jnl
Big Data Res.
David Chalupa, Ken A. Hawick, James Alfred Walker
2017 A conf
DATE
Simon J. Bale, Pedro B. Campos, Martin A. Trefzer, James Alfred Walker, Andy M. Tyrrell
2017 J jnl
IEEE Trans. Computers
Martin A. Trefzer, David M. R. Lawson, Simon J. Bale, James Alfred Walker, Andy M. Tyrrell
2017 conf
ASP-DAC
Simon J. Bale, James Alfred Walker, Martin A. Trefzer, Andy M. Tyrrell
2015 J jnl
IET Comput. Digit. Tech.
Martin A. Trefzer, James Alfred Walker, Simon J. Bale, Andrew M. Tyrrell
2015 ch.
Evolvable Hardware
James Alfred Walker
2015 B conf
CEC
Yuan Wang, James Alfred Walker, Simon J. Bale, Martin A. Trefzer, Andy M. Tyrrell
2014 conf
AHS
David M. R. Lawson, James Alfred Walker, Martin A. Trefzer, Simon J. Bale, Andy M. Tyrrell
2014 conf
ICES
Yang Xiao, James Alfred Walker, Simon J. Bale, Martin A. Trefzer, Andy M. Tyrrell
2014 conf
ICES
David M. R. Lawson, James Alfred Walker, Martin A. Trefzer, Simon J. Bale, Andy M. Tyrrell
2014 conf
ICES
Yuan Wang, Simon J. Bale, James Alfred Walker, Martin A. Trefzer, Andy M. Tyrrell
2014 conf
ICES
Pedro B. Campos, Martin A. Trefzer, James Alfred Walker, Simon J. Bale, Andy M. Tyrrell
2014 B conf
IEEE Congress on Evolutionary Computation
Yang Xiao, Martin A. Trefzer, James Alfred Walker, Simon J. Bale, Andy M. Tyrrell
2013 conf
ICES
James Alfred Walker, Martin Trefzer, Andy M. Tyrrell
2013 conf
ICES
James Alfred Walker, Martin Trefzer, Simon J. Bale, Andy M. Tyrrell
2013 B conf
IEEE Congress on Evolutionary Computation
Pedro B. Campos, David M. R. Lawson, Simon J. Bale, James Alfred Walker, Martin Trefzer, Andy M. Tyrrell
2013 J jnl
IEEE Trans. Computers
James Alfred Walker, Martin Trefzer, Simon J. Bale, Andy M. Tyrrell
2012 J jnl
Int. J. Adapt. Resilient Auton. Syst.
James Alfred Walker, Yang Liu, Gianluca Tempesti, Jon Timmis, Andy M. Tyrrell
2012 ed.
IPCAT
Michael A. Lones, Stephen L. Smith, Sarah A. Teichmann, Felix Naef, James Alfred Walker, Martin Trefzer
2011 B conf
EuroGP
Yang Liu, Gianluca Tempesti, James Alfred Walker, Jon Timmis, Andrew M. Tyrrell, Paul Bremner
2011 conf
ACSCC
Martin Trefzer, James Alfred Walker, Andy M. Tyrrell
2011 ch.
Cartesian Genetic Programming
Lukás Sekanina, James Alfred Walker, Paul Kaufmann, Marco Platzner
2011 ch.
Cartesian Genetic Programming
Stephen L. Smith, James Alfred Walker, Julian F. Miller
2011 ch.
Cartesian Genetic Programming
James Alfred Walker, Julian F. Miller, Paul Kaufmann, Marco Platzner
2011 J jnl
Genet. Program. Evolvable Mach.
James Alfred Walker, James A. Hilder, Dave Reid, Asen Asenov, Scott Roy, Campbell Millar, Andy M. Tyrrell
2010 conf
ICES
James Alfred Walker, Yang Liu, Gianluca Tempesti, Andy M. Tyrrell
2010 conf
ICES
Paul Bremner, Mohammad Samie, Gabriel Dragffy, Anthony G. Pipe, James Alfred Walker, Andy M. Tyrrell
2010 conf
ICES
James Alfred Walker, James A. Hilder, Andy M. Tyrrell
2010 conf
AHS
James A. Hilder, James Alfred Walker, Andy M. Tyrrell
2009 conf
WEAH
James A. Hilder, James Alfred Walker, Andy M. Tyrrell
2009 B conf
IEEE Congress on Evolutionary Computation
James A. Hilder, James Alfred Walker, Andy M. Tyrrell
2009 J jnl
Genet. Program. Evolvable Mach.
James Alfred Walker, Katharina Völk, Stephen L. Smith, Julian Francis Miller
2009 B conf
IEEE Congress on Evolutionary Computation
James Alfred Walker, James A. Hilder, Andy M. Tyrrell
2008 conf
ICES
James Alfred Walker, James A. Hilder, Andy M. Tyrrell
2008 J jnl
IEEE Trans. Evol. Comput.
James Alfred Walker, Julian Francis Miller
2007 A conf
GECCO
Janet Clegg, James Alfred Walker, Julian Francis Miller
2007 B conf
EuroGP
James Alfred Walker, Julian Francis Miller
2007 B conf
EuroGP
James Alfred Walker, Julian Francis Miller
2007 A conf
GECCO
James Alfred Walker, Julian Francis Miller
2007
James Alfred Walker
2006 A conf
GECCO
James Alfred Walker, Julian Francis Miller, Rachel Cavill
2006 A conf
GECCO
James Alfred Walker, Julian Francis Miller
2005 conf
ICES
James Alfred Walker, Julian Francis Miller
2005 A conf
GECCO
James Alfred Walker, Julian Francis Miller
2004 B conf
EuroGP
James Alfred Walker, Julian Francis Miller
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