Ioannis Kalatzis

32 papers C 4Journal 22Unranked 6
YearRankTypeTitle / Venue / Authors
2026 J jnl
Algorithms
Panagiotis Korkidis, Anastasios I. Dounis, Ioannis Theocharakis, Emmanouil I. Athanasiadis, Spiros Kostopoulos, Aikaterini Skouroliakou, Errikos M. Ventouras, Anastasios Raptis, Konstantinos Spanos, Konstantinos Moulakakis, Athanasios Giannoukas, Ioannis Kakisis, Christos Manopoulos, Ioannis Kalatzis
2025 J jnl
J. Imaging
Christos Ch. Andrianos, Spiros Kostopoulos, Ioannis Kalatzis, Dimitris T. Glotsos, Pantelis A. Asvestas, Dionisis A. Cavouras, Emmanouil I. Athanasiadis
2024 conf
SMAP
Kontopodis E. Lefteris, Dionisis Cavouras, Serafeim Christodoulos, Ioannis Kalatzis, Skouroliakou Aikaterini
2021 J jnl
Mach. Vis. Appl.
Angeliki D. Theodosi, Sotiris Ouzounis, Spiros Kostopoulos, Dimitris Glotsos, Ioannis Kalatzis, Vassiliki Tzelepi, Panagiota Ravazoula, Pantelis Asvestas, Dionisis A. Cavouras, George Sakellaropoulos
2017 J jnl
Int. J. Medical Informatics
Spiros Kostopoulos, Pantelis A. Asvestas, Ioannis Kalatzis, George Sakellaropoulos, Theofilos H. Sakkis, Dionisis A. Cavouras, Dimitris T. Glotsos
2017 J jnl
J. Digit. Imaging
Spiros Kostopoulos, Panagiota Ravazoula, Pantelis Asvestas, Ioannis Kalatzis, George Xenogiannopoulos, Dionisis A. Cavouras, Dimitris Glotsos
2012 J jnl
Comput. Biol. Medicine
Konstantinos Sidiropoulos, Dimitris Glotsos, Spiros Kostopoulos, Panagiota Ravazoula, Ioannis Kalatzis, Dionisis A. Cavouras, T. John Stonham
2011 J jnl
Comput. Methods Programs Biomed.
Emmanouil Athanasiadis, Dionisis A. Cavouras, Spiros Kostopoulos, Dimitris Glotsos, Ioannis Kalatzis, George Nikiforidis
2010 J jnl
Comput. Methods Programs Biomed.
Dimitris Glotsos, Ioannis Kalatzis, Pantelis Theocharakis, Pantelis Georgiadis, Antonis Daskalakis, Kostas Ninos, Pavlos Zoumboulis, Anna Filippidou, Dionisis A. Cavouras
2010 J jnl
Comput. Methods Programs Biomed.
Panagiotis Bougioukos, Dimitris Glotsos, Dionisis A. Cavouras, Antonis Daskalakis, Ioannis Kalatzis, Spiros Kostopoulos, George Nikiforidis, Anastasios Bezerianos
2010 J jnl
Comput. Intell. Neurosci.
Errikos M. Ventouras, Periklis Y. Ktonas, Hara Tsekou, Thomas Paparrigopoulos, Ioannis Kalatzis, Constantin R. Soldatos
2009 J jnl
IEEE Trans. Inf. Technol. Biomed.
Emmanouil Athanasiadis, Dionisis A. Cavouras, Panagiota Spyridonos, Dimitris Glotsos, Ioannis Kalatzis, George Nikiforidis
2009 J jnl
IEEE Trans. Inf. Technol. Biomed.
Emmanouil Athanasiadis, Dionisis A. Cavouras, Dimitris Glotsos, Pantelis Georgiadis, Ioannis Kalatzis, George Nikiforidis
2008 J jnl
Comput. Biol. Medicine
Antonis Daskalakis, Spiros Kostopoulos, Panagiota Spyridonos, Dimitris Glotsos, Panagiota Ravazoula, Maria Kardari, Ioannis Kalatzis, Dionisis A. Cavouras, George Nikiforidis
2008 J jnl
Comput. Methods Programs Biomed.
Dimitris Glotsos, Ioannis Kalatzis, Panagiota Spyridonos, Spiros Kostopoulos, Antonis Daskalakis, Emmanouil Athanasiadis, Panagiota Ravazoula, George Nikiforidis, Dionisis A. Cavouras
2008 J jnl
Comput. Methods Programs Biomed.
Pantelis Georgiadis, Dionisis A. Cavouras, Ioannis Kalatzis, Antonis Daskalakis, George C. Kagadis, Koralia Sifaki, Menelaos Malamas, George Nikiforidis, Ekaterini Solomou
2008 C conf
BIBE
Errikos M. Ventouras, Periklis Y. Ktonas, Hara Tsekou, Thomas Paparrigopoulos, Ioannis Kalatzis, Constantin R. Soldatos
2007 J jnl
Comput. Graph.
Spiros Kostopoulos, Dimitris Glotsos, George C. Kagadis, Antonis Daskalakis, Panagiota Spyridonos, Ioannis Kalatzis, M. Karamessini, T. Petsas, Dionisis A. Cavouras, George Nikiforidis
2007 C conf
CAIP
Emmanouil Athanasiadis, Dionisis A. Cavouras, Panagiota Spyridonos, Ioannis Kalatzis, George Nikiforidis
2007 C conf
CAIP
Spiros Kostopoulos, Dionisis A. Cavouras, Antonis Daskalakis, Ioannis Kalatzis, Panagiotis Bougioukos, George C. Kagadis, Panagiota Ravazoula, George Nikiforidis
2007 C conf
CAIP
Panagiotis Bougioukos, Dionisis A. Cavouras, Antonis Daskalakis, Ioannis Kalatzis, Spiros Kostopoulos, Pantelis Georgiadis, George Nikiforidis, Anastasios Bezerianos
2007 conf
ICCSA (3)
Panagiotis Bougioukos, Dionisis A. Cavouras, Antonis Daskalakis, Ioannis Kalatzis, George Nikiforidis, Anastasios Bezerianos
2007 J jnl
Comput. Biol. Medicine
Ioannis Boniatis, Dionisis A. Cavouras, Lena Costaridou, Ioannis Kalatzis, Elias E. Panagiotopoulos, George Panayiotakis
2007 conf
IbPRIA (1)
Antonis Daskalakis, Dionisis A. Cavouras, Panagiotis Bougioukos, Spiros Kostopoulos, Ioannis Kalatzis, George C. Kagadis, George Nikiforidis
2007 conf
ICCSA (3)
Antonis Daskalakis, Dionisis A. Cavouras, Panagiotis Bougioukos, Spiros Kostopoulos, Pantelis Georgiadis, Ioannis Kalatzis, George C. Kagadis, George Nikiforidis
2007 J jnl
Bioinform.
Antonis Daskalakis, Dionisis A. Cavouras, Panagiotis Bougioukos, Spiros Kostopoulos, Dimitris Glotsos, Ioannis Kalatzis, George C. Kagadis, Christos Argyropoulos, George Nikiforidis
2007 conf
ICCSA (3)
Pantelis Georgiadis, Dionisis A. Cavouras, Ioannis Kalatzis, Antonis Daskalakis, George C. Kagadis, Koralia Sifaki, Menelaos Malamas, George Nikiforidis, Ekaterini Solomou
2006 conf
ISBMDA
Ioannis Boniatis, Dionisis A. Cavouras, Lena Costaridou, Ioannis Kalatzis, Elias E. Panagiotopoulos, George Panayiotakis
2006 J jnl
Medical Biol. Eng. Comput.
Ioannis Boniatis, Lena Costaridou, Dionisis A. Cavouras, Ioannis Kalatzis, Elias E. Panagiotopoulos, George Panayiotakis
2005 J jnl
Pattern Recognit. Lett.
Ioannis Kalatzis, Nikolaos Piliouras, Eric Ventouras, Charalabos C. Papageorgiou, Ioannis A. Liappas, Chrysoula C. Nikolaou, Andreas D. Rabavilas, Dionisis A. Cavouras
2004 J jnl
Comput. Methods Programs Biomed.
Ioannis Kalatzis, Nikolaos Piliouras, Eric Ventouras, Charalabos C. Papageorgiou, Andreas D. Rabavilas, Dionisis A. Cavouras
2004 J jnl
Pattern Recognit. Lett.
Nikolaos Piliouras, Ioannis Kalatzis, Pantelis Theocharakis, Nikos Dimitropoulos, Dionisis A. Cavouras
sql/redb_js_tables.sql
← Index sql/redb_js_tables.sql sql
-- JavaScript malware analysis tables
-- Engine: ReplacingMergeTree(analysis_date) — latest analysis wins on re-processing
--
-- File order:
--   1. redb_js_features
--   2. redb_js_suspicious_apis
--   3. redb_js_deobfuscation
--   4. code_text_content              (generic text-content table; JS today,
--                                      PowerShell / Python / email / extracted
--                                      PDF / Office text in the future)
--   5. redb_iocs source_type ALTER    (extends Enum8 with text_raw/text_normalized
--                                      so JS — and any future text-based pipeline —
--                                      can distinguish IOCs found in the raw vs
--                                      normalised surface)
--   6. redb_iocs ioc_type ALTER       (adds registry_key=42 so HKLM/HKCU/HKEY_*
--                                      keys are extracted alongside file paths)
--
-- Decoded strings from JS still go into the shared code_binja_strings_raw
-- table (same schema used by DecompileBinja and DecompileAPK). JS
-- string_encoding values: hex, unicode, charcode, base64, concat. Plain long
-- literals are not extracted here — they're already in code_text_content and
-- scraped by the IOC pipeline over text_raw/text_normalized.
-- string_offset is the line number in the source file.
--
-- redb_js_features.script_type values (file format / container, first match):
--   jse, wsf, hta, embedded_html, wscript, esm, node_module, standalone, unknown
-- redb_js_features.detected_environment values (runtime by API surface, first
-- match):
--   wscript, browser_extension, service_worker, deno, node, browser, unknown

-- 1. Core features & obfuscation metrics (1 row per sample)
CREATE TABLE IF NOT EXISTS redb_js_features (
    sha256 FixedString(64),
    line_count UInt32,
    char_count UInt64,
    text_entropy Float64,
    max_line_length UInt32,
    avg_line_length Float64,
    is_minified UInt8,
    is_likely_obfuscated UInt8,
    obfuscator_name LowCardinality(String),
    obfuscation_score UInt8,
    obfuscation_techniques Array(String),
    eval_count UInt32,
    function_constructor_count UInt32,
    settimeout_setinterval_count UInt32,
    document_write_count UInt32,
    innerhtml_count UInt32,
    unescape_count UInt32,
    fromcharcode_count UInt32,
    atob_count UInt32,
    decodeuri_count UInt32,
    total_function_count UInt32,
    total_variable_count UInt32,
    max_nesting_depth UInt16,
    avg_identifier_length Float64,
    hex_string_count UInt32,
    unicode_escape_count UInt32,
    long_string_count UInt32,
    base64_string_count UInt32,
    comment_ratio Float64,
    script_type LowCardinality(String),
    detected_environment LowCardinality(String),
    analysis_date DateTime64(3, 'UTC')
) ENGINE = ReplacingMergeTree(analysis_date)
ORDER BY sha256;

-- 2. Suspicious API calls (multi-row per sample)
--
-- `revealed_by_deobf` is 1 when the API only appears after the deobfuscation
-- pass (i.e. the call site is hidden in the raw artefact and surfaces only in
-- text_normalized). Useful for filtering "what did normalisation actually
-- buy us" without re-running the diff.
CREATE TABLE IF NOT EXISTS redb_js_suspicious_apis (
    sha256 FixedString(64),
    api_name String,
    api_category LowCardinality(String),
    call_count UInt32,
    line_numbers Array(UInt32),
    context_snippet String,
    revealed_by_deobf UInt8,
    analysis_date DateTime64(3, 'UTC')
) ENGINE = ReplacingMergeTree(analysis_date)
ORDER BY (sha256, api_name);

-- 3. Deobfuscation results (1 row per sample)
CREATE TABLE IF NOT EXISTS redb_js_deobfuscation (
    sha256 FixedString(64),
    deobfuscator_used LowCardinality(String),
    deobfuscation_successful UInt8,
    original_size UInt64,
    deobfuscated_size UInt64,
    size_change_ratio Float64,
    original_entropy Float64,
    deobfuscated_entropy Float64,
    new_strings_found UInt32,
    new_apis_found UInt32,
    deobfuscated_sha256 FixedString(64),
    analysis_date DateTime64(3, 'UTC')
) ENGINE = ReplacingMergeTree(analysis_date)
ORDER BY sha256;

-- 4. Generic text-content table for any text-based artefact (JS today;
--    PowerShell, Python, plain text, email bodies, extracted PDF/Office text
--    in the future). One row per sha256. content_type carries the magika
--    label so callers can filter without joining other tables.
CREATE TABLE IF NOT EXISTS code_text_content (
    sha256 FixedString(64),
    content_type LowCardinality(String),
    text_raw String CODEC(ZSTD(3)),
    text_normalized Nullable(String) CODEC(ZSTD(3)),
    normalizer_used Nullable(String),
    analysis_date DateTime64(3, 'UTC')
) ENGINE = ReplacingMergeTree(analysis_date)
ORDER BY sha256;

-- 5. Extend redb_iocs.source_type Enum8 with two universal text-content
--    surfaces: text_raw (the artefact's original text) and text_normalized
--    (a deobfuscated/canonicalised form). Used by the JS IOC extraction
--    pipeline today; any future text-based pipeline (PowerShell, PDF, etc.)
--    plugs into the same two values.
--
-- Existing rows keep their stored integer values; only newly-inserted rows
-- can use 4/5. The MODIFY COLUMN must list the full final enum, including
-- the existing values (1/2/3) — ClickHouse rejects partial alters.
ALTER TABLE redb_iocs
    MODIFY COLUMN source_type
    Enum8('decompiled_function'=1, 'disassembled_function'=2, 'string'=3,
          'text_raw'=4, 'text_normalized'=5);

-- 6. Extend redb_iocs.ioc_type Enum8 with registry_key=42. Windows registry
--    paths (HKLM\..., HKCU\..., HKEY_LOCAL_MACHINE\...) are a distinct class
--    of IOC from filesystem paths and were previously extracted by nothing.
--    Same MODIFY COLUMN constraint as the source_type alter — the full final
--    enum must be listed.
ALTER TABLE redb_iocs
    MODIFY COLUMN ioc_type
    Enum8('ipv4'=1, 'ipv6'=2, 'fqdn'=3, 'url'=4, 'email'=5, 'server'=6,
          'hash_md5'=10, 'hash_sha1'=11, 'hash_sha256'=12,
          'cve'=20, 'cwe'=21, 'cpe'=22,
          'crypto_btc'=30, 'crypto_eth'=31, 'crypto_xrp'=32, 'crypto_bch'=33,
          'crypto_ada'=34, 'crypto_substrate'=35,
          'path_linux'=40, 'path_windows'=41, 'registry_key'=42,
          'onion'=50);

-- 7. Migrate redb_js_features to the two-tier obfuscation verdict.
--    `is_obfuscated` (binary heuristic at score >=40) is renamed to
--    `is_likely_obfuscated` (heuristic at >=60 + ≥1 strong signal, OR
--    js-x-ray flagged the obfuscator family). `obfuscator_name` is the
--    family name reported by @nodesecure/js-x-ray (jsfuck, obfuscator.io,
--    morse, jjencode, freejsobfuscator, ...) or empty when not detected.
--
--    Run once against an existing deployment. The CREATE TABLE above
--    already reflects the post-migration shape, so fresh installs skip this.
ALTER TABLE redb_js_features
    RENAME COLUMN is_obfuscated TO is_likely_obfuscated;
ALTER TABLE redb_js_features
    ADD COLUMN IF NOT EXISTS obfuscator_name LowCardinality(String) AFTER is_likely_obfuscated;

-- 8. Harmonise code_text_content column names with redb_iocs.source_type
--    enum values. The enum already uses `text_raw` / `text_normalized` for
--    the surface labels; the table previously stored the same data under
--    `content_raw` / `content_normalized`, forcing every join across the two
--    to translate names. Renaming the columns produces a self-documenting
--    schema where `redb_iocs.source_type='text_raw'` points directly at
--    `code_text_content.text_raw`.
--
--    Run once against an existing deployment. The CREATE TABLE above
--    already reflects the post-migration shape, so fresh installs skip this.
ALTER TABLE code_text_content
    RENAME COLUMN content_raw TO text_raw;
ALTER TABLE code_text_content
    RENAME COLUMN content_normalized TO text_normalized;

-- 9. Add revealed_by_deobf flag to redb_js_suspicious_apis. The strings/APIs
--    extractors now scan both the raw source and the deobfuscated text so APIs
--    hidden behind one obfuscation layer (Vjw0rm-style array.join + eval,
--    Dean-Edwards packers, ...) surface in the table. The flag is 1 only when
--    the API was *not* found in the raw source — querying for it isolates
--    "deobf-only" findings without joining redb_js_deobfuscation.
--
--    Run once against an existing deployment. The CREATE TABLE above
--    already reflects the post-migration shape, so fresh installs skip this.
ALTER TABLE redb_js_suspicious_apis
    ADD COLUMN IF NOT EXISTS revealed_by_deobf UInt8 AFTER context_snippet;