Malicious PDF — malware analysis report

Static analysis result for SHA-256 991fd8643f33e5df…

MALICIOUS

PDF

45.5 KB Created: 2021-06-08 09:59:49 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-31
MD5: e4208a4e8d3d7b7fef0c3b9a5b10e1ae SHA-1: 78be9d07f80bef4becdea0e802a943757ab0e4fb SHA-256: 991fd8643f33e5df559e6ef6a6fcdef6eb05357cb7a3bbd6d6076110ae590ba8
200 Risk Score

Malware Insights

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

The PDF document contains a lure for a 'free generator / game hack' which redirects to a known malicious URL. The document also displays a fake CAPTCHA, likely to trick the user into interacting with the malicious link. The ML classifier also flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9864

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.
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • 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 https://netcdn.tw/app/431946152/how-to-hack-roblox-games-2021-game-hack In PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/can-you-make-a-minecraft-server-for-free_GM479516143.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/free-coin-master-spins-2021_GM406889139.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/optifine-mcpe_GM479516143.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/how-to-get-free-robux-promo-codes_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/how-to-get-1-million-robux-for-free-2021_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/free-coins-coin-master-link-today_GM406889139.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/free-minecraft-alt-generator_GM479516143.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/100-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/hack-coin-master-android-2021_GM406889139.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/free-roblox-glasses_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/free-robux-pin-codes_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/robux-free-gift-card-org-hack_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/free-robux-hack-no-verification_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/free-robux-just-click_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/robux-free-2021_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/nuevo-hack-de-robux-2021-funcionando_GM431946152.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/coin-master-32-hack-apk-download_GM406889139.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/coin-master-hack-unlimited-spins-apk_GM406889139.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/minecraft-bedrock-free_GM479516143.pdfIn PDF document text
    • http://digilib.ulm.ac.id/pusat/repository/hack-the-game-coin-master_GM406889139.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
stream_004_off00005164.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5164 25564 bytes
SHA-256: 712b63f9f67a36156af6d6cf7c9072182bb74c818bb70f63de42da81dfa06d54
font_01_sfnt_off00008ccb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8CCB 19008 bytes
SHA-256: 54185099cc4abbf44b659913d751f0abcfae5b4a0a2fe836ec4e1151ba78df66

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