H. Michael Zhang

44 papers A* 1A 1Journal 29Unranked 13
YearRankTypeTitle / Venue / Authors
2026 J jnl
IEEE Trans. Intell. Transp. Syst.
Ammar Haydari, Dongjie Chen, Zhengfeng Lai, H. Michael Zhang, Chen-Nee Chuah
2025 J jnl
CoRR
Xianyue Peng, Shenyang Chen, H. Michael Zhang
2025 J jnl
IEEE Trans. Intell. Transp. Syst.
Xianyue Peng, Shenyang Chen, Hang Gao, Hao Wang, H. Michael Zhang
2025 conf
ISVC (1)
Amirali Ataee Naeini, Ashkan Teymouri, Ghazaleh Jafarsalehi, H. Michael Zhang
2025 J jnl
Transp. Sci.
Shi-Teng Zheng, Rui Jiang, H. Michael Zhang, Junfang Tian, Ruidong Yan, Bin Jia, Ziyou Gao
2024 J jnl
CoRR
Di Chen, Jia Li, H. Michael Zhang
2023 J jnl
CoRR
Xianyue Peng, Hang Gao, Hao Wang, H. Michael Zhang
2023 J jnl
Transp. Sci.
Rui Jiang, Xiao Han, Xiao-Yan Sun, Kai-Jia Sun, Wen-Xu Wang, H. Michael Zhang, Boyu Zhang, Zi-You Gao
2022 conf
ITSC
Chia-Cheng Yen, Hang Gao, H. Michael Zhang
2022 A conf
ACSAC
Ammar Haydari, Chen-Nee Chuah, H. Michael Zhang, Jane MacFarlane, Sean Peisert
2022 J jnl
IEEE Trans. Intell. Transp. Syst.
Chia-Cheng Yen, Dipak Ghosal, H. Michael Zhang, Chen-Nee Chuah
2021 J jnl
CoRR
Ammar Haydari, H. Michael Zhang, Chen-Nee Chuah, Jane MacFarlane, Sean Peisert
2021 conf
VTC Spring
Ammar Haydari, H. Michael Zhang, Chen-Nee Chuah, Dipak Ghosal
2021 J jnl
J. Intell. Transp. Syst.
Rui Ma, Shenyang Chen, H. Michael Zhang
2020 conf
ITSC
Chia-Cheng Yen, Dipak Ghosal, H. Michael Zhang, Chen-Nee Chuah
2020 J jnl
Veh. Commun.
Bryan Ching, Mani Amoozadeh, Chen-Nee Chuah, H. Michael Zhang, Dipak Ghosal
2020 J jnl
IEEE Trans. Intell. Transp. Syst.
Bin Yu, Ke Zhu, Kaiteng Wu, H. Michael Zhang
2019 J jnl
J. Intell. Transp. Syst.
Huajun Chai, Rui Ma, H. Michael Zhang
2019 conf
ANT/EDI40
Mani Amoozadeh, Bryan Ching, Chen-Nee Chuah, Dipak Ghosal, H. Michael Zhang
2018 J jnl
IEEE Trans. Veh. Technol.
Jian Wu, Dipak Ghosal, H. Michael Zhang, Chen-Nee Chuah
2018 J jnl
Neurocomputing
Bin Yu, Kaiteng Wu, Ke Zhu, Yuhan Ji, H. Michael Zhang, Xinwen Yang
2018 J jnl
IEEE Trans. Intell. Transp. Syst.
Jian Sun, Tienan Li, Mengqiao Yu, H. Michael Zhang
2018 conf
VNC
Chia-Cheng Yen, Dipak Ghosal, H. Michael Zhang, Chen-Nee Chuah, Hao Chen
2018 J jnl
CoRR
Bin Yu, Ke Zhu, Kaiteng Wu, H. Michael Zhang
2015 J jnl
Veh. Commun.
Mani Amoozadeh, Hui Deng, Chen-Nee Chuah, H. Michael Zhang, Dipak Ghosal
2015 J jnl
IEEE Commun. Mag.
Mani Amoozadeh, Arun Raghuramu, Chen-Nee Chuah, Dipak Ghosal, H. Michael Zhang, Jeff Rowe, Karl N. Levitt
2014 J jnl
Simul. Model. Pract. Theory
Bin Yu, H. Michael Zhang, Zhongren Wang, Dong Bian
2013 J jnl
IEEE Trans. Veh. Technol.
Kartik Pandit, Dipak Ghosal, H. Michael Zhang, Chen-Nee Chuah
2013 J jnl
Networks Heterog. Media
Alexandre M. Bayen, Hélène Frankowska, Jean-Patrick Lebacque, Benedetto Piccoli, H. Michael Zhang
2012 J jnl
IEEE Trans. Veh. Technol.
Bojin Liu, Dipak Ghosal, Chen-Nee Chuah, H. Michael Zhang
2011 conf
VTC Fall
Bojin Liu, Dipak Ghosal, Yachao Dong, Chen-Nee Chuah, H. Michael Zhang
2011 J jnl
IEEE Wirel. Commun.
Behrooz Khorashadi, Fred Bojin Liu, Dipak Ghosal, H. Michael Zhang, Chen-Nee Chuah
2010 A* conf
INFOCOM
Bojin Liu, Behrooz Khorashadi, Dipak Ghosal, Chen-Nee Chuah, H. Michael Zhang
2009 J jnl
Math. Comput. Model.
Yu Marco Nie, H. Michael Zhang
2009 J jnl
IEEE Commun. Mag.
Bojin Liu, Behrooz Khorashadi, Haining Du, Dipak Ghosal, Chen-Nee Chuah, H. Michael Zhang
2008 J jnl
Comput. Aided Civ. Infrastructure Eng.
Yu Marco Nie, Jingtao Ma, H. Michael Zhang
2008 J jnl
Comput. Aided Civ. Infrastructure Eng.
Enrique F. Castillo, H. Michael Zhang, Hesham Rakha, Yasuo Asakura
2008 J jnl
Transp. Sci.
Yu Marco Nie, H. Michael Zhang
2007 conf
ICC
Behrooz Khorashadi, Andrew Chen, Dipak Ghosal, Chen-Nee Chuah, H. Michael Zhang
2006 conf
ITSC
Jingtao Ma, Yu Marco Nie, H. Michael Zhang
2006 conf
ITSC
Wilfred W. Recker, H. Michael Zhang, Lianyu Chu, Anthony Chen, Michael McNally
2006 conf
ITSC
Wei Shen, Yu Marco Nie, H. Michael Zhang
2006 conf
ITSC
Andrew Chen, Behrooz Khorashadi, Chen-Nee Chuah, Dipak Ghosal, H. Michael Zhang
2004 conf
MWCN
Howard CheHao Chang, Haining Du, Joey Anda, Chen-Nee Chuah, Dipak Ghosal, H. Michael Zhang
redb/extractors/decompiler/DecompileAPK.py
← Index redb/extractors/decompiler/DecompileAPK.py python
"""APK Code Analysis Extractor.

Decompiles and disassembles APK DEX bytecode at the method level,
producing per-method content and reference records analogous to
the Binary Ninja code_binja_* tables.

Uses androguard + JADX + apktool to replicate Binary Ninja analysis
depth for Android applications.
"""

import gc
import hashlib
import inspect
import logging
import os
import threading
import time
from datetime import datetime, timezone
from typing import Any, Dict, Optional

from redb.extractors.decompiler.apk.analyzer import APKCodeAnalyzer
from redb.extractors.enum import Tag
from redb.extractors.extractor import Extractor


class DecompileAPK(Extractor):
    """APK code analysis extractor — produces multi-table ClickHouse export.

    Follows the same pattern as DecompileBinja for consistency.
    """

    def __init__(
        self,
        filepath,
        log,
        exporters=None,
        index_prefix=None,
        known_benign=False,
        known_malicious=False,
        filetype=None,
        decompile_modules=None,
    ):
        super().__init__(
            filepath,
            log,
            exporters,
            index_prefix,
            known_benign=known_benign,
            known_malicious=known_malicious,
        )
        self.log.debug(inspect.currentframe().f_code.co_name)
        self.analysis_results = None
        self.analyzer = None
        self.filetype = filetype or "apk"
        self.decompile_modules = decompile_modules or {"all"}

        try:
            self.APK_DECOMPILE_TIMEOUT = int(
                os.getenv("APK_DECOMPILE_TIMEOUT", "600")
            )
        except ValueError:
            self.log.warning(
                "Invalid APK_DECOMPILE_TIMEOUT value, using default of 600 seconds"
            )
            self.APK_DECOMPILE_TIMEOUT = 600

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.cleanup_run()

    def calculate_md5(self, input_str):
        """Calculate MD5 hash of a string."""
        return hashlib.md5(input_str.encode("utf-8")).hexdigest()

    def cleanup_run(self):
        """Clean up after analysis."""
        try:
            if self.analyzer:
                self.analyzer.cleanup()
                self.analyzer = None
            gc.collect()
        except Exception as e:
            self.log.error(f"Error in cleanup: {e}")

    def analyze_apk(self) -> Optional[Dict[str, Any]]:
        """Run APK code analysis and return results."""
        self.log.debug("Starting APK code analysis")
        try:
            self.analyzer = APKCodeAnalyzer(
                filepath=self.filepath,
                timeout=self.APK_DECOMPILE_TIMEOUT,
                log=self.log,
                decompile_modules=self.decompile_modules,
            )
            results = self.analyzer.extract()
            return results
        except Exception as e:
            self.log.error(f"Error in APK code analysis: {e}")
            import traceback
            self.log.error(f"Traceback: {traceback.format_exc()}")
            return None
        finally:
            self.cleanup_run()

    def extract(self):
        """Extract and process all analysis results.

        Uses daemon thread with timeout, same pattern as DecompileBinja.
        """
        self.log.debug(inspect.currentframe().f_code.co_name)

        extraction_completed = False
        extraction_result = False
        extraction_error = None

        def do_extraction():
            nonlocal extraction_completed, extraction_result, extraction_error
            try:
                results = self.analyze_apk()
                if not results:
                    extraction_result = False
                else:
                    self.analysis_results = results
                    self.analysis_results["sha256"] = self.sha256
                    self.analysis_results["sha1"] = self.sha1
                    self.analysis_results["md5"] = self.md5
                    extraction_result = True
            except Exception as e:
                extraction_error = e
                extraction_result = False
            finally:
                extraction_completed = True

        extraction_thread = threading.Thread(target=do_extraction)
        extraction_thread.daemon = True
        extraction_thread.start()

        start_time = time.time()
        while (
            not extraction_completed
            and (time.time() - start_time) < self.APK_DECOMPILE_TIMEOUT
        ):
            time.sleep(1)

        if not extraction_completed:
            self.log.error(
                f"APK extraction timed out after {self.APK_DECOMPILE_TIMEOUT} seconds"
            )
            self.cleanup_run()
            return None

        if extraction_error:
            self.log.error(f"Error in APK extraction: {extraction_error}")
            return None

        return self.analysis_results if extraction_result else None

    def prepare_export_data(self, exporter_type: str) -> Any:
        """Prepare data for database export."""
        self.log.debug(inspect.currentframe().f_code.co_name)
        if not self.analysis_results:
            return None

        if exporter_type == "ClickHouseExporter":
            now = datetime.now(timezone.utc)
            export = {"multi_table": True}

            # Table 1: Decompiled method content
            if self.analysis_results.get("decompiled_content"):
                export["decompiled_content"] = {
                    "table": "code_apk_decompiled_methods_content",
                    "data": [
                        [
                            f["decompiled_method_hash"],
                            f["decompiled_method"],
                            f.get("decompiled_method_type", "UNKNOWN"),
                            1 if f.get("decompiled_has_string_encryption") else 0,
                            1 if f.get("decompiled_has_reflection_calls") else 0,
                            1 if f.get("decompiled_excessive_goto_count") else 0,
                            now,
                        ]
                        for f in self.analysis_results["decompiled_content"]
                    ],
                    "column_names": [
                        "decompiled_method_hash",
                        "decompiled_method",
                        "decompiled_method_type",
                        "decompiled_has_string_encryption",
                        "decompiled_has_reflection_calls",
                        "decompiled_excessive_goto_count",
                        "analysis_date",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "String",
                        "Enum8('USER'=1, 'LIBRARY'=2, 'UNKNOWN'=5)",
                        "UInt8",
                        "UInt8",
                        "UInt8",
                        "DateTime64(3, 'UTC')",
                    ],
                }

            # Table 2: Decompiled method references
            if self.analysis_results.get("decompiled_refs"):
                export["decompiled_refs"] = {
                    "table": "code_apk_decompiled_methods_references",
                    "data": [
                        [
                            self.analysis_results["sha256"],
                            f["decompiled_method_hash"],
                            f.get("smali_method_hash"),
                            f.get("decompiled_class_name", ""),
                            f.get("decompiled_method_name", ""),
                            f.get("decompiled_method_signature", ""),
                            f.get("decompiled_method_prototype", ""),
                            f.get("functions_caller", []),
                            f.get("functions_call", []),
                            now,
                        ]
                        for f in self.analysis_results["decompiled_refs"]
                    ],
                    "column_names": [
                        "sha256",
                        "decompiled_method_hash",
                        "smali_method_hash",
                        "decompiled_class_name",
                        "decompiled_method_name",
                        "decompiled_method_signature",
                        "decompiled_method_prototype",
                        "functions_caller",
                        "functions_call",
                        "analysis_date",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "FixedString(64)",
                        "Nullable(FixedString(64))",
                        "LowCardinality(String)",
                        "LowCardinality(String)",
                        "String",
                        "String",
                        "Array(String)",
                        "Array(String)",
                        "DateTime64(3, 'UTC')",
                    ],
                }

            # Table 3: Smali method content
            if self.analysis_results.get("smali_content"):
                export["smali_content"] = {
                    "table": "code_apk_smali_methods_content",
                    "data": [
                        [
                            f["smali_method_hash"],
                            f["smali_method"],
                            f.get("smali_method_type", "UNKNOWN"),
                            f.get("smali_instructions_count", 0),
                            f.get("smali_register_count", 0),
                            1 if f.get("smali_has_string_encryption") else 0,
                            1 if f.get("smali_has_reflection_calls") else 0,
                            1 if f.get("smali_excessive_goto_count") else 0,
                            f.get("smali_flattened_score", 0.0),
                            f.get("smali_mba_score", 0.0),
                            now,
                        ]
                        for f in self.analysis_results["smali_content"]
                    ],
                    "column_names": [
                        "smali_method_hash",
                        "smali_method",
                        "smali_method_type",
                        "smali_instructions_count",
                        "smali_register_count",
                        "smali_has_string_encryption",
                        "smali_has_reflection_calls",
                        "smali_excessive_goto_count",
                        "smali_flattened_score",
                        "smali_mba_score",
                        "analysis_date",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "String",
                        "Enum8('USER'=1, 'LIBRARY'=2, 'UNKNOWN'=5)",
                        "UInt32",
                        "UInt16",
                        "UInt8",
                        "UInt8",
                        "UInt8",
                        "Float64",
                        "Float64",
                        "DateTime64(3, 'UTC')",
                    ],
                }

            # Table 4: Smali method references
            if self.analysis_results.get("smali_refs"):
                export["smali_refs"] = {
                    "table": "code_apk_smali_methods_references",
                    "data": [
                        [
                            self.analysis_results["sha256"],
                            f["smali_method_hash"],
                            f.get("decompiled_method_hash"),
                            f.get("smali_class_name", ""),
                            f.get("smali_method_name", ""),
                            f.get("smali_method_signature", ""),
                            now,
                        ]
                        for f in self.analysis_results["smali_refs"]
                    ],
                    "column_names": [
                        "sha256",
                        "smali_method_hash",
                        "decompiled_method_hash",
                        "smali_class_name",
                        "smali_method_name",
                        "smali_method_signature",
                        "analysis_date",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "FixedString(64)",
                        "Nullable(FixedString(64))",
                        "LowCardinality(String)",
                        "LowCardinality(String)",
                        "String",
                        "DateTime64(3, 'UTC')",
                    ],
                }

            # Table 5: Method similarity metrics (content-based fuzzy matching)
            if self.analysis_results.get("similarity_metrics"):
                export["method_similarity_metrics"] = {
                    "table": "code_apk_method_similarity_metrics",
                    "data": [
                        [
                            f["smali_method_hash"],
                            f.get("ssdeep_smali"),
                            f.get("tlsh_smali"),
                            f.get("ssdeep_smali_normalized"),
                            f.get("tlsh_smali_normalized"),
                            f.get("minhash", []),
                            now,
                        ]
                        for f in self.analysis_results["similarity_metrics"]
                    ],
                    "column_names": [
                        "smali_method_hash",
                        "ssdeep_smali",
                        "tlsh_smali",
                        "ssdeep_smali_normalized",
                        "tlsh_smali_normalized",
                        "minhash",
                        "analysis_date",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "Nullable(String)",
                        "Nullable(FixedString(72))",
                        "Nullable(String)",
                        "Nullable(FixedString(72))",
                        "Array(UInt8)",
                        "DateTime64(3, 'UTC')",
                    ],
                }

            # Table 5b: CFG method features (structural/topological)
            if self.analysis_results.get("cfg"):
                export["cfg_methods"] = {
                    "table": "code_apk_cfg_methods",
                    "data": [
                        [
                            cfg["smali_method_hash"],
                            cfg["cfg_topology_hash"],
                            cfg["block_count"],
                            cfg["edge_count"],
                            cfg.get("cfg_instructions_count", 0),
                            cfg.get("call_count", 0),
                            cfg["cyclomatic_complexity"],
                            cfg.get("loop_count", 0),
                            cfg.get("max_depth", 0),
                            cfg.get("max_fan_out", 0),
                            cfg.get("md_index_topdown", 0),
                            cfg.get("md_index_bottomup", 0),
                            cfg.get("prime_product_smali", 0),
                            cfg.get("cfg_feature_tlsh"),
                            cfg.get("wl_minhash", []),
                            cfg.get("bb_features", []),
                            cfg.get("cfg_adjacency", []),
                            now,
                        ]
                        for cfg in self.analysis_results["cfg"]
                        if cfg is not None
                    ],
                    "column_names": [
                        "smali_method_hash",
                        "cfg_topology_hash",
                        "block_count",
                        "edge_count",
                        "cfg_instructions_count",
                        "call_count",
                        "cyclomatic_complexity",
                        "loop_count",
                        "max_depth",
                        "max_fan_out",
                        "md_index_topdown",
                        "md_index_bottomup",
                        "prime_product_smali",
                        "cfg_feature_tlsh",
                        "wl_minhash",
                        "bb_features",
                        "cfg_adjacency",
                        "analysis_date",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "FixedString(16)",
                        "UInt16",
                        "UInt16",
                        "UInt32",
                        "UInt16",
                        "UInt16",
                        "UInt16",
                        "UInt16",
                        "UInt16",
                        "UInt64",
                        "UInt64",
                        "UInt64",
                        "Nullable(FixedString(72))",
                        "Array(UInt8)",
                        "Array(Array(UInt16))",
                        "Array(UInt32)",
                        "DateTime64(3, 'UTC')",
                    ],
                }

            # Table 6: Strings — reuse code_binja_strings_raw for cross-format correlation
            # DEX strings are MUTF-8; string_raw = string since no encoding difference
            if self.analysis_results.get("strings"):
                export["strings_raw"] = {
                    "table": "code_binja_strings_raw",
                    "data": [
                        [
                            self.analysis_results["sha256"],
                            s["string"],
                            s["string"],  # string_raw = string (MUTF-8 decoded to UTF-8)
                            s.get("string_encoding", "UTF8"),
                            s.get("string_offset", 0),
                            s.get("string_length", len(s["string"])),
                            s.get("string_length", len(s["string"])),  # string_raw_length = string_length
                            s.get("string_entropy", 0.0),
                        ]
                        for s in self.analysis_results["strings"]
                    ],
                    "column_names": [
                        "sha256",
                        "string",
                        "string_raw",
                        "string_encoding",
                        "string_offset",
                        "string_length",
                        "string_raw_length",
                        "string_entropy",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "String",
                        "String",
                        "LowCardinality(String)",
                        "UInt64",
                        "UInt32",
                        "UInt32",
                        "Float32",
                    ],
                }

            # Table 7: Analysis errors
            if self.analysis_results.get("analysis_errors"):
                export["analysis_errors"] = {
                    "table": "code_apk_analysis_errors",
                    "data": [
                        [
                            self.analysis_results["sha256"],
                            f.get("class_name"),
                            f.get("method_name"),
                            f.get("error_location", "unknown"),
                            f.get("error_message", ""),
                            f.get("error_type", "unknown"),
                            self.calculate_md5(
                                f"{f.get('error_message', '')}"
                                f"{f.get('class_name', '')}"
                                f"{f.get('method_name', '')}"
                                f"{f.get('error_location', 'unknown')}"
                            ),
                            "new",
                            now,
                        ]
                        for f in self.analysis_results["analysis_errors"]
                    ],
                    "column_names": [
                        "sha256",
                        "class_name",
                        "method_name",
                        "error_location",
                        "error_message",
                        "error_type",
                        "error_hash",
                        "status",
                        "analysis_date",
                    ],
                    "column_type_names": [
                        "FixedString(64)",
                        "Nullable(String)",
                        "Nullable(String)",
                        "LowCardinality(String)",
                        "Nullable(String)",
                        "Nullable(String)",
                        "FixedString(32)",
                        "Enum8('new'=1, 'investigating'=2, 'fixed'=3, 'wontfix'=4)",
                        "DateTime64(3, 'UTC')",
                    ],
                }

            return export

        return None

    def tag(self) -> str:
        """Return the tag for this extractor."""
        return Tag.APK_DECOMPILED.value

    def get_clickhouse_table(self) -> str:
        """Not used directly as we're handling multiple tables."""
        pass