Jan Elen

40 papers A 2B 2Journal 27Unranked 8
YearRankTypeTitle / Venue / Authors
2025 J jnl
Technol. Knowl. Learn.
Rani Van Schoors, Jan Elen, Annelies Raes, Stefanie Vanbecelaere, Kamakshi Rajagopal, Fien Depaepe
2024 J jnl
J. Comput. High. Educ.
Bekalu Ferede, Jan Elen, Wim Van Petegem, Adula Bekele Hunde, Katie Goeman
2024 conf
ALL@AIED
Kristina Krushinskaia, Jan Elen, Annelies Raes
2024 conf
AIED Companion (2)
Kristina Krushinskaia, Jan Elen, Annelies Raes
2023 J jnl
Educ. Inf. Technol.
Bekalu Ferede, Jan Elen, Wim Van Petegem, Adula Bekele, Katie Goeman
2022 J jnl
Comput. Educ.
Bekalu Ferede, Jan Elen, Wim Van Petegem, Adula Bekele Hunde, Katie Goeman
2022 J jnl
Educ. Inf. Technol.
Bekalu Ferede, Jan Elen, Wim Van Petegem, Adula Bekele Hunde, Katie Goeman
2022 J jnl
J. Comput. High. Educ.
Bekalu Ferede, Jan Elen, Wim Van Petegem, Adula Bekele Hunde, Katie Goeman
2021 J jnl
Br. J. Educ. Technol.
Rani Van Schoors, Jan Elen, Annelies Raes, Fien Depaepe
2020 J jnl
Technol. Knowl. Learn.
Stijn Van Laer, Jan Elen
2019 conf
CIbSE
Estefanía Serral, Jenny Ruiz, Jan Elen, Monique Snoeck
2019 J jnl
Comput. Educ.
Stijn Van Laer, Jan Elen
2018 conf
ICLS
Charlotte Larmuseau, Jan Elen, Piet Desmet, Fien Depaepe
2018 A conf
LAK
Charlotte Larmuseau, Jan Elen, Fien Depaepe
2017 J jnl
Educ. Inf. Technol.
Stijn Van Laer, Jan Elen
2017 J jnl
Br. J. Educ. Technol.
Pieter Wouters, Herre van Oostendorp, Judith ter Vrugte, Sylke Vandercruysse, Ton de Jong, Jan Elen
2016 J jnl
Comput. Hum. Behav.
Sylke Vandercruysse, Judith ter Vrugte, Ton de Jong, Pieter Wouters, Herre van Oostendorp, Lieven Verschaffel, Mariola Moeyaert, Jan Elen
2015 J jnl
Comput. Educ.
Judith ter Vrugte, Ton de Jong, Sylke Vandercruysse, Pieter Wouters, Herre van Oostendorp, Jan Elen
2015 conf
GALA
Pieter Wouters, Herre van Oostendorp, Judith ter Vrugte, Sylke Vandercruysse, Ton de Jong, Jan Elen
2015 J jnl
Comput. Hum. Behav.
Norma A. Juarez Collazo, Jan Elen, Geraldine Clarebout
2015 J jnl
J. Comput. Assist. Learn.
Judith ter Vrugte, Ton de Jong, Pieter Wouters, Sylke Vandercruysse, Jan Elen, Herre van Oostendorp
2013 J jnl
Comput. Educ.
Griet Lust, Jan Elen, Geraldine Clarebout
2013 J jnl
Comput. Hum. Behav.
Griet Lust, Jan Elen, Geraldine Clarebout
2012 J jnl
J. Comput. High. Educ.
Griet Lust, Jan Elen, Geraldine Clarebout
2012 J jnl
Comput. Hum. Behav.
Griet Lust, Norma A. Juarez Collazo, Jan Elen, Geraldine Clarebout
2012 B conf
ICALT
Sylke Vandercruysse, Jan Elen, Geraldine Clarebout
2011 J jnl
Comput. Educ.
Griet Lust, Mieke Vandewaetere, Eva Ceulemans, Jan Elen, Geraldine Clarebout
2010 J jnl
J. Educ. Technol. Soc.
Jan Elen, Geraldine Clarebout, Frederick Kwaku Sarfo, Lambertus Philippus (Flip) Louw, Johanna Pöysä-Tarhonen, Nick Stassens
2009 J jnl
Comput. Hum. Behav.
Geraldine Clarebout, Jan Elen
2009 J jnl
Comput. Hum. Behav.
Lai Jiang, Jan Elen, Geraldine Clarebout
2009 J jnl
Comput. Hum. Behav.
Geraldine Clarebout, Holger Horz, Jan Elen
2008 conf
ICLS (1)
Geraldine Clarebout, Joke Coens, Jan Elen
2007 J jnl
Comput. Hum. Behav.
Jan Elen, Geraldine Clarebout
2006 J jnl
Comput. Hum. Behav.
Geraldine Clarebout, Jan Elen
2005 conf
CELDA
Geraldine Clarebout, Jan Elen
2005 ch.
Encyclopedia of Information Science and Technology (II)
Geraldine Clarebout, Jan Elen, Joost Lowyck, Jef Van den Enden, Erwin Van den Ende
2005 B conf
ICALT
Frederick Kwaku Sarfo, Jan Elen
2005 A conf
AIED
Geraldine Clarebout, Jan Elen
2001 J jnl
Comput. Hum. Behav.
Geraldine Clarebout, Jan Elen
1996 conf
CALISCE
Koen Hendrikx, Jan Elen, Henk J. Olivié
redb/extractors/elf_extractors/elf_features.py
← Index redb/extractors/elf_extractors/elf_features.py python
import inspect
import json
from datetime import datetime, timezone
from typing import Any

from elftools.elf.elffile import ELFFile
from elftools.common.exceptions import ELFError

from redb.extractors.enum import Tag
from redb.extractors.elf_extractor import ELFExtractor
from redb.models.dataclasses import ELFFeatures


class ELFFeaturesExtractor(ELFExtractor):

    def __init__(
        self,
        filepath,
        log,
        exporters=None,
        index_prefix=None,
        elastic_index=None,
        known_benign=False,
        known_malicious=False,
        elf=None,
    ):
        super().__init__(
            filepath,
            log,
            exporters,
            index_prefix,
            elastic_index,
            known_benign,
            known_malicious,
            elf,
        )
        self.elf_features = None
        self.elastic_index = self.index_prefix + "-elf_features"
        self.log.debug(inspect.currentframe().f_code.co_name)

    def _extract_header_data(self):
        """Extract ELF header data using pyelftools."""
        self.log.debug(inspect.currentframe().f_code.co_name)

        def extract_header(elf):
            # Initialize result with safe defaults
            result = {
                'ei_class': 0, 'ei_data': 0, 'ei_version': 0, 'ei_osabi': 0, 'ei_abiversion': 0,
                'e_type': 0, 'e_machine': 0, 'e_version': 0, 'e_entry': 0, 'e_flags': 0,
                'ei_class_str': 'unknown', 'ei_data_str': 'unknown', 'ei_osabi_str': 'unknown',
                'e_type_str': 'unknown', 'e_machine_str': 'unknown'
            }

            # Try to get the main header - if this fails, we can't extract anything
            try:
                header = elf.header
            except Exception as e:
                self.log.warning(f"Could not access ELF header: {e}")
                return result

            # Try to get e_ident section
            ident = None
            try:
                ident = header.get('e_ident', {})
            except Exception as e:
                self.log.warning(f"Could not access e_ident: {e}")

            # Extract EI_CLASS (32/64 bit)
            try:
                if ident:
                    ei_class_raw = ident.get('EI_CLASS', 'ELFCLASSNONE')
                    result['ei_class'] = 2 if ei_class_raw == 'ELFCLASS64' else 1 if ei_class_raw == 'ELFCLASS32' else 0
                    result['ei_class_str'] = '64-bit' if ei_class_raw == 'ELFCLASS64' else '32-bit' if ei_class_raw == 'ELFCLASS32' else 'unknown'
            except Exception as e:
                self.log.warning(f"Could not extract EI_CLASS: {e}")

            # Extract EI_DATA (endianness)
            try:
                if ident:
                    ei_data_raw = ident.get('EI_DATA', 'ELFDATANONE')
                    result['ei_data'] = 1 if ei_data_raw == 'ELFDATA2LSB' else 2 if ei_data_raw == 'ELFDATA2MSB' else 0
                    result['ei_data_str'] = 'Little-endian' if ei_data_raw == 'ELFDATA2LSB' else 'Big-endian' if ei_data_raw == 'ELFDATA2MSB' else 'unknown'
            except Exception as e:
                self.log.warning(f"Could not extract EI_DATA: {e}")

            # Extract EI_VERSION
            try:
                if ident:
                    ei_version_raw = ident.get('EI_VERSION', 0)
                    # Convert string like 'EV_CURRENT' to integer
                    if isinstance(ei_version_raw, str):
                        version_map = {'EV_NONE': 0, 'EV_CURRENT': 1}
                        result['ei_version'] = version_map.get(ei_version_raw, 1)
                    else:
                        result['ei_version'] = ei_version_raw
            except Exception as e:
                self.log.warning(f"Could not extract EI_VERSION: {e}")

            # Extract EI_OSABI
            try:
                if ident:
                    ei_osabi_raw = ident.get('EI_OSABI', 'ELFOSABI_SYSV')
                    osabi_map = {
                        'ELFOSABI_SYSV': 0, 'ELFOSABI_HPUX': 1, 'ELFOSABI_NETBSD': 2,
                        'ELFOSABI_LINUX': 3, 'ELFOSABI_SOLARIS': 6, 'ELFOSABI_FREEBSD': 9
                    }
                    result['ei_osabi'] = osabi_map.get(ei_osabi_raw, 0)
                    result['ei_osabi_str'] = ei_osabi_raw.replace('ELFOSABI_', '') if ei_osabi_raw and ei_osabi_raw.startswith('ELFOSABI_') else str(ei_osabi_raw) if ei_osabi_raw else 'unknown'
            except Exception as e:
                self.log.warning(f"Could not extract EI_OSABI: {e}")

            # Extract EI_ABIVERSION
            try:
                if ident:
                    result['ei_abiversion'] = ident.get('EI_ABIVERSION', 0)
            except Exception as e:
                self.log.warning(f"Could not extract EI_ABIVERSION: {e}")

            # Extract e_type (file type)
            try:
                e_type_raw = header.get('e_type', 'ET_NONE')
                type_map = {
                    'ET_NONE': 0, 'ET_REL': 1, 'ET_EXEC': 2, 'ET_DYN': 3, 'ET_CORE': 4
                }
                result['e_type'] = type_map.get(e_type_raw, 0)
                result['e_type_str'] = e_type_raw.replace('ET_', '') if e_type_raw and e_type_raw.startswith('ET_') else str(e_type_raw) if e_type_raw else 'unknown'
            except Exception as e:
                self.log.warning(f"Could not extract e_type: {e}")

            # Extract e_machine (architecture)
            try:
                e_machine_raw = header.get('e_machine', 0)
                # Map machine strings to integers and human-readable names
                # https://github.com/eliben/pyelftools/blob/main/elftools/elf/enums.py
                # https://github.com/torvalds/linux/blob/master/include/uapi/linux/elf-em.h
                # https://refspecs.linuxfoundation.org/elf/elf.pdf
                machine_int_map = {
                    'EM_NONE': 0, 'EM_M32': 1, 'EM_SPARC': 2, 'EM_386': 3,
                    'EM_68K': 4, 'EM_88K': 5, 'EM_860': 7, 'EM_MIPS': 8,
                    'EM_S370': 9, 'EM_MIPS_RS3_LE': 10, 'EM_PARISC': 15,
                    'EM_VPP500': 17, 'EM_SPARC32PLUS': 18, 'EM_960': 19,
                    'EM_PPC': 20, 'EM_PPC64': 21, 'EM_S390': 22, 'EM_V800': 36,
                    'EM_FR20': 37, 'EM_RH32': 38, 'EM_RCE': 39, 'EM_ARM': 40,
                    'EM_ALPHA': 41, 'EM_SH': 42, 'EM_SPARCV9': 43, 'EM_TRICORE': 44,
                    'EM_ARC': 45, 'EM_H8_300': 46, 'EM_H8_300H': 47, 'EM_H8S': 48,
                    'EM_H8_500': 49, 'EM_IA_64': 50, 'EM_MIPS_X': 51, 'EM_COLDFIRE': 52,
                    'EM_68HC12': 53, 'EM_X86_64': 62, 'EM_AARCH64': 183, 'EM_RISCV': 243,
                }
                machine_str_map = {
                    'EM_386': 'x86', 'EM_X86_64': 'x86_64', 'EM_ARM': 'ARM', 'EM_AARCH64': 'ARM64',
                    'EM_MIPS': 'MIPS', 'EM_PPC': 'PowerPC', 'EM_PPC64': 'PowerPC64',
                    'EM_SPARC': 'SPARC', 'EM_SPARCV9': 'SPARC64', 'EM_RISCV': 'RISC-V',
                    'EM_IA_64': 'IA-64', 'EM_S390': 'S390', 'EM_SH': 'SuperH',
                }
                if isinstance(e_machine_raw, str):
                    result['e_machine'] = machine_int_map.get(e_machine_raw, 0)
                    result['e_machine_str'] = machine_str_map.get(e_machine_raw, e_machine_raw.replace('EM_', '') if e_machine_raw.startswith('EM_') else e_machine_raw)
                else:
                    result['e_machine'] = e_machine_raw
                    result['e_machine_str'] = str(e_machine_raw)
            except Exception as e:
                self.log.warning(f"Could not extract e_machine: {e}")

            # Extract e_version
            try:
                e_version_raw = header.get('e_version', 0)
                # Convert string like 'EV_CURRENT' to integer
                if isinstance(e_version_raw, str):
                    version_map = {'EV_NONE': 0, 'EV_CURRENT': 1}
                    result['e_version'] = version_map.get(e_version_raw, 1)
                else:
                    result['e_version'] = e_version_raw
            except Exception as e:
                self.log.warning(f"Could not extract e_version: {e}")

            # Extract e_entry (entry point)
            try:
                result['e_entry'] = header.get('e_entry', 0)
            except Exception as e:
                self.log.warning(f"Could not extract e_entry: {e}")

            # Extract e_flags
            try:
                result['e_flags'] = header.get('e_flags', 0)
            except Exception as e:
                self.log.warning(f"Could not extract e_flags: {e}")

            return result

        try:
            return self._with_elf_file(extract_header)
        except Exception as e:
            self.log.error(f"Error extracting header data {self.hash.sha256}: {e}")
            return None

    def _count_dynamic_symbols(self):
        """Count symbols in dynamic symbol table."""
        def count_dynsym(elf):
            dynsym_section = elf.get_section_by_name('.dynsym')
            if dynsym_section and hasattr(dynsym_section, 'num_symbols'):
                return dynsym_section.num_symbols()
            return 0

        try:
            result = self._with_elf_file(count_dynsym)
            return result if result is not None else 0
        except Exception as e:
            self.log.error(f"Error counting dynamic symbols: {e}")
            return 0

    def _count_relocations(self):
        """Count total relocations across all sections."""
        def count_relocs(elf):
            reloc_count = 0
            for section in elf.iter_sections():
                if hasattr(section, 'iter_relocations'):
                    try:
                        reloc_count += section.num_relocations()
                    except:
                        # Some sections might not support num_relocations()
                        for _ in section.iter_relocations():
                            reloc_count += 1
            return reloc_count

        try:
            result = self._with_elf_file(count_relocs)
            return result if result is not None else 0
        except Exception as e:
            self.log.error(f"Error counting relocations: {e}")
            return 0

    def _has_gnu_hash(self):
        """Check if GNU hash table is present."""
        def check_gnu_hash(elf):
            gnu_hash_section = elf.get_section_by_name('.gnu.hash')
            return gnu_hash_section is not None

        try:
            result = self._with_elf_file(check_gnu_hash)
            return bool(result)
        except Exception as e:
            self.log.error(f"Error checking GNU hash: {e}")
            return False

    def _has_fortify(self):
        """Check if binary has fortify source protection."""
        def check_fortify(elf):
            # Look for fortified function symbols
            fortify_symbols = ['__printf_chk', '__sprintf_chk', '__snprintf_chk',
                             '__strcpy_chk', '__strcat_chk', '__memcpy_chk']

            for section in elf.iter_sections():
                if hasattr(section, 'iter_symbols'):
                    for symbol in section.iter_symbols():
                        if symbol.name in fortify_symbols:
                            return True
            return False

        try:
            result = self._with_elf_file(check_fortify)
            return bool(result)
        except Exception as e:
            self.log.error(f"Error checking fortify: {e}")
            return False

    def tag(self):
        return Tag.ELF_FEATURES.value if hasattr(Tag, 'ELF_FEATURES') else "elf_features"

    def extract(self):
        try:
            self.log.debug(inspect.currentframe().f_code.co_name)

            # Check if file is valid ELF
            if not self._is_elf_file():
                self.log.error(f"No valid ELF file for {self.hash.sha256}")
                return None

            # Extract header data (now always returns a result, even with defaults)
            header_data = self._extract_header_data()
            if not header_data:
                self.log.error(f"Complete failure to extract any header data for {self.hash.sha256}")
                return None

            # Extract binary properties
            is_64bit = 1 if self._is_64bit() else 0
            is_stripped = 1 if self._is_stripped() else 0
            is_pie = 1 if self._is_pie() else 0
            has_canary = 1 if self._has_stack_protection() else 0
            has_nx = 1 if self._has_nx_bit() else 0
            has_relro = 1 if self._has_relro() else 0
            has_fortify = 1 if self._has_fortify() else 0

            # Extract counts
            number_of_segments = self._count_segments()
            number_of_sections = self._count_sections()
            number_of_symbols = self._count_symbols()
            number_of_dynamic_symbols = self._count_dynamic_symbols()
            number_of_relocations = self._count_relocations()
            number_of_dependencies = len(self._get_dependencies())

            # Extract build information
            build_id = self._get_build_id()
            gnu_hash_present = 1 if self._has_gnu_hash() else 0
            has_debug_info = 1 if self._has_debug_info() else 0

            self.elf_features = ELFFeatures(
                # ELF Header data
                ei_class=header_data['ei_class'],
                ei_data=header_data['ei_data'],
                ei_version=header_data['ei_version'],
                ei_osabi=header_data['ei_osabi'],
                ei_abiversion=header_data['ei_abiversion'],
                e_type=header_data['e_type'],
                e_machine=header_data['e_machine'],
                e_version=header_data['e_version'],
                e_entry=header_data['e_entry'],
                e_flags=header_data['e_flags'],
                # Human readable values
                ei_class_str=header_data['ei_class_str'],
                ei_data_str=header_data['ei_data_str'],
                ei_osabi_str=header_data['ei_osabi_str'],
                e_type_str=header_data['e_type_str'],
                e_machine_str=header_data['e_machine_str'],
                # Binary properties
                is_64bit=is_64bit,
                is_stripped=is_stripped,
                is_pie=is_pie,
                has_canary=has_canary,
                has_nx=has_nx,
                has_relro=has_relro,
                has_fortify=has_fortify,
                # Counts
                number_of_segments=number_of_segments,
                number_of_sections=number_of_sections,
                number_of_symbols=number_of_symbols,
                number_of_dynamic_symbols=number_of_dynamic_symbols,
                number_of_relocations=number_of_relocations,
                number_of_dependencies=number_of_dependencies,
                # Build information
                build_id=build_id,
                gnu_hash_present=gnu_hash_present,
                has_debug_info=has_debug_info,
            )

            return self.elf_features

        except Exception as e:
            self.log.error(f"Error extracting ELF features {self.hash.sha256}: {e}")
            return None

    def prepare_export_data(self, exporter_type: str) -> Any:
        self.log.debug(inspect.currentframe().f_code.co_name)

        if exporter_type == "ElasticsearchExporter":
            return self.elf_features
        elif exporter_type == "ClickHouseExporter":
            try:
                if not self.elf_features:
                    return None

                # Prepare data array matching the schema
                data = [[
                    self.sha256,
                    self.md5,
                    self.sha1,

                    # ELF Header data
                    self.elf_features.ei_class,
                    self.elf_features.ei_data,
                    self.elf_features.ei_version,
                    self.elf_features.ei_osabi,
                    self.elf_features.ei_abiversion,
                    self.elf_features.e_type,
                    self.elf_features.e_machine,
                    self.elf_features.e_version,
                    self.elf_features.e_entry,
                    self.elf_features.e_flags,

                    # Human readable values
                    self.elf_features.ei_class_str,
                    self.elf_features.ei_data_str,
                    self.elf_features.ei_osabi_str,
                    self.elf_features.e_type_str,
                    self.elf_features.e_machine_str,

                    # Binary properties
                    self.elf_features.is_64bit,
                    self.elf_features.is_stripped,
                    self.elf_features.is_pie,
                    self.elf_features.has_canary,
                    self.elf_features.has_nx,
                    self.elf_features.has_relro,
                    self.elf_features.has_fortify,

                    # Counts
                    self.elf_features.number_of_segments,
                    self.elf_features.number_of_sections,
                    self.elf_features.number_of_symbols,
                    self.elf_features.number_of_dynamic_symbols,
                    self.elf_features.number_of_relocations,
                    self.elf_features.number_of_dependencies,

                    # Build information
                    self.elf_features.build_id,
                    self.elf_features.gnu_hash_present,
                    self.elf_features.has_debug_info,

                    # Analysis metadata
                    datetime.now(timezone.utc)
                ]]

                column_names = [
                    'sha256', 'md5', 'sha1',
                    'ei_class', 'ei_data', 'ei_version', 'ei_osabi', 'ei_abiversion',
                    'e_type', 'e_machine', 'e_version', 'e_entry', 'e_flags',
                    'ei_class_str', 'ei_data_str', 'ei_osabi_str', 'e_type_str', 'e_machine_str',
                    'is_64bit', 'is_stripped', 'is_pie', 'has_canary', 'has_nx', 'has_relro', 'has_fortify',
                    'number_of_segments', 'number_of_sections', 'number_of_symbols',
                    'number_of_dynamic_symbols', 'number_of_relocations', 'number_of_dependencies',
                    'build_id', 'gnu_hash_present', 'has_debug_info',
                    'analysis_date'
                ]

                column_type_names = [
                    'FixedString(64)', 'FixedString(32)', 'FixedString(40)',
                    "Enum8('32-bit'=1, '64-bit'=2)",
                    "Enum8('Little-endian'=1, 'Big-endian'=2)",
                    'UInt8',
                    "Enum8('SYSV'=0, 'HPUX'=1, 'NETBSD'=2, 'LINUX'=3, 'SOLARIS'=6, 'FREEBSD'=9)",
                    'UInt8',
                    "Enum8('NONE'=0, 'REL'=1, 'EXEC'=2, 'DYN'=3, 'CORE'=4)",
                    'UInt16', 'UInt32', 'UInt64', 'UInt32',
                    'LowCardinality(String)', 'LowCardinality(String)', 'LowCardinality(String)',
                    'LowCardinality(String)', 'LowCardinality(String)',
                    'UInt8', 'UInt8', 'UInt8', 'UInt8', 'UInt8', 'UInt8', 'UInt8',
                    'UInt16', 'UInt16', 'UInt32', 'UInt32', 'UInt32', 'UInt16',
                    'Nullable(String)', 'UInt8', 'UInt8',
                    'DateTime64(3, \'UTC\')'
                ]

                if not data:
                    return None

                return (data, column_names, column_type_names)

            except Exception as e:
                self.log.error(f"Error preparing export data: {e}")
                raise

    def get_clickhouse_table(self) -> str:
        return "redb_elf_features"