Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef6c467da4ab6f66…

MALICIOUS

PDF

33.1 KB Created: 2021-07-04 08:35:15 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-16
MD5: e890516456a9bc8e93601968a7a57ad0 SHA-1: 0eb380e8f7216153d89fdd3b70aa1c2d0d42ccfc SHA-256: ef6c467da4ab6f66a672f0dad7dcf065a355e1057b30d5d33b7526d66e136198
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a malformed stream and links to known malicious redirector infrastructure, specifically http://netcdn.tw/app/479516143/is-minecraft-education-edition-free-game-hack. The document body and embedded URLs suggest a lure for free game hacks or generators, likely to download a second-stage payload. The ML classifier strongly indicates malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • PDF links to a 'free generator / game hack' redirector critical PDF_GAME_HACK_REDIRECT_LURE
    PDF's clickable action targets a redirector of the form /app/<id>/<slug>-game-hack — the landing-page shape of a large SEO 'free spins / generator / game hack' lure family that funnels victims through rotating disposable hosts to a malware/scam payload. The multi-link variants also trip ML/link-farm rules; this catches the single-link variants that otherwise score clean. CRITICAL on its own: the /app/<id>/<slug>-game-hack path shape is unambiguous scam infra, and the host rotates so a host-list match can't be relied on.
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://netcdn.tw/app/479516143/is-minecraft-education-edition-free-game-hack In PDF document text
    • http://elibrary.fl.unud.ac.id/repository/roblox-shoulder-pets-free_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/roblox-assassin-moving-cheat_GM431946152.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/coin-master-online-hack-link_GM406889139.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/roblox-got-hacked-2021_GM431946152.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/earn-robux_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/coin-master-hack-spins-apk-download_GM406889139.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/free-robux-hack-video_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/free-spins-from-coin-master_GM406889139.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/free-robux-no-gift-card_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/coin-master-online-hack-no-human-verification_GM406889139.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/robux-today_GM431946152.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/easy-robux-hack-on-roblox-2021_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/free-limiteds-on-roblox_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/roblox-im-freaking-out-hack_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/minecraft-hack-client-download_GM479516143.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/coin-master-hack-download-android_GM406889139.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/get-free-money-in-roblox-jailbreak_GM431946152.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/free-robux-wheel_GM431946152.pdfIn PDF document text
    • http://elibrary.fl.unud.ac.id/repository/roblox-noob-skin-free_GM431946152.pdfIn PDF document text
    • http://www.elibrary.fl.unud.ac.id/repository/roblox-robux-hack-generator_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00002e7f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2E7F 21868 bytes
SHA-256: 32cb0450f1436c9c4f09ac940ca1797d8ae7eee9995c23021211a2475417e6ca
font_01_sfnt_off00005e7b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5E7B 18312 bytes
SHA-256: eecac33872f4bf99db25d0145d9acf2ab6d7270ffb9fefd56cdfeedcf9aa8f6d

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