Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4c8fc1593d1efc9…

MALICIOUS

PDF

33.7 KB Created: 2021-07-05 14:58:25 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 26887b536a44d069f3d2dc4f7e8dbbb9 SHA-1: babfa052e7e9a055b8cb971671f9eef4cbd069c6 SHA-256: c4c8fc1593d1efc9c17138fa7b8601a14c8f10d2912da76a37a10e9546455081
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a lure for a 'free Robux generator' that redirects to malicious infrastructure, as indicated by critical heuristic firings. The document body and embedded URLs reinforce this social engineering tactic. While no scripts were explicitly extracted, the malformed stream length and ML classifier suggest active content is present, likely JavaScript, attempting to facilitate the redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9852

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/431946152/free-robux-generator-no-human-verification-or-surveys-game-hack In PDF document text
    • https://perpustakaan.stifar.ac.id/repository/how-to-get-free-robux-without-downloading-apps-2021_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/hack-on-god-simulator-on-roblox_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/roblox-how-to-hack-through-walls_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/free-unlimited-coin-master-online-tool_GM406889139.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/how-to-get-free-robux-games_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/how-to-hack-roblox-crimnal-vs-swat_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/minecraft-free_GM479516143.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/is-there-any-way-to-gte-free-robux_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/hilton-hotel-roblox-hacks_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/coin-master-daily-free-spins-hack_GM406889139.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/roblox-redeem-card-codes-2021-free-robux_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/denisdaily-free-robux-app_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/how-to-get-free-robux-with-editthiscookie_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/10-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/roblox-free-plane_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/free-robux-cards-giveaway_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/free-admin-roblox_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/hack-para-mad-city-roblox-2021_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/is-there-any-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://perpustakaan.stifar.ac.id/repository/how-to-hack-roblox-ultimate-driving_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_off00002c17.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2C17 22208 bytes
SHA-256: 86bfc95817d57826685cbdaf78447649e5cc8fc0edce7cf84b5c86e7a6840e1c
font_01_sfnt_off00005d48.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5D48 19628 bytes
SHA-256: dd0ace09804e6f63f156f321225227e2c42173c1a42082ec6161e9275733ded2

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