Malicious PDF — malware analysis report

Static analysis result for SHA-256 d77fa8d04db3a6c6…

MALICIOUS

PDF

45.8 KB Created: 2021-06-07 03:36:58 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-23
MD5: 2a1114cfbdeeb8ffc3dd2bc8669a606e SHA-1: 64cb991f938d4a35cb9574d2235aaf0df015aa7d SHA-256: d77fa8d04db3a6c6eb21d397e9975e42102024b2c40dd16c26a88db51f2c82bb
200 Risk Score

Malware Insights

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

The PDF document contains a lure for free in-game currency, presenting a fake CAPTCHA to trick users into interacting with malicious links. The embedded URL, https://netcdn.tw/app/431946152/unlimited-free-robux-2021-game-hack, is identified as a malicious redirector. While no scripts were explicitly extracted, the PDF structure and heuristics suggest it's designed to exploit user interaction, potentially leading to further compromise.

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/unlimited-free-robux-2021-game-hack In PDF document text
    • https://library.sttbandung.ac.id/repository/robux-com-free_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/daily-free-spin-coin-master-link_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/give-me-robux-now_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/pokemon-go-free-8-bit_GM1094591345.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/moonactive-coin-master-free-spins_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-spins-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-hack-coin-master-computer_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/roblox-free-robux-no-human-verification_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/hacks-for-minecraft-windows-10_GM479516143.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/robux-free-gift-card-org-hack_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/minecraft-112-2-hacked-client_GM479516143.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-robux-no-verify_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/coin-master-free-spins-and-free-coins_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/roblox-free-hair-boy_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/roblox-robux-hack_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/roblox-free-robux-com_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-robux-without-survey_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-spins-coin-master-hack-2021_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-printable-roblox-coloring-pages_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-get-free-robux-no-human-verification_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
stream_004_off000050e6.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x50E6 27096 bytes
SHA-256: a23593ec88863b90c4fd9951181eb2b9d338658cff8778e1eb393fc2d1e7de58
font_01_sfnt_off00008d5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8D5A 19336 bytes
SHA-256: 362f57482f90385cc327a9cf59e8269d2cb1dcadbc0bd8d076e878e2ae20117f

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