Malicious PDF — malware analysis report

Static analysis result for SHA-256 efb6e964c3f6e614…

MALICIOUS

PDF

46.0 KB Created: 2021-05-14 12:04:44 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 9151d4dbbfad41f508ba9cededb4c89d SHA-1: 5b24d9d041120f4f609b029f5c49d53293e0e519 SHA-256: efb6e964c3f6e61469ca35fcf4da8e1d45353d62664d2924e6d9605f4a91696e
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded links that redirect to malicious infrastructure, specifically promoting 'free Robux' and game hacks. The ML classifier also flagged this PDF as malicious. The presence of multiple links and the lure content suggest a phishing or scam attempt, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9432

Heuristics 4

  • 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.
  • 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.xyz/app/431946152/free-robux-live-game-hack In PDF document text
    • http://www.alpaca-buitensport.nl/images/free-robux-no-verification-no-survey_GM431946152.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/free-coins-and-spins-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/coin-master-link_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/minecraft-pe-hacks-ios_GM479516143.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/free-coin-master-spins-2021_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/hack-coin-master-apk-33_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/how-to-get-free-robux-by-playing-games_GM431946152.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/how-to-hack-robux_GM431946152.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/minecraft-sign-up-free_GM479516143.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/earn-free-robux-on-roblox_GM431946152.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/coin-master-70-spin-link-2021_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/coin-master-game-free-spin_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/free-coins-and-spins-in-coin-master_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/coin-master-free-spins-daily_GM406889139.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/free-robux-generator-codes_GM431946152.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/minecraft-free-online-unblocked_GM479516143.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/robux-for-offers_GM431946152.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/easy-ways-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/how-to-install-minecraft-for-free-on-ios_GM479516143.pdfIn PDF document text
    • http://www.alpaca-buitensport.nl/images/how-to-get-free-robux-fast-and-easy_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off00004b76.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4B76 25636 bytes
SHA-256: dfc4aabbf55cb9b8e48c8aac733a612be31273fca06116e39783fd66640ff5a7
font_01_sfnt_off0000876d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x876D 2880 bytes
SHA-256: 552e62132cae3603ce0819827e44d96a992bd06014cc5080bf3af4b2ea155b3e
font_02_sfnt_off00009145.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9145 18248 bytes
SHA-256: 2e5a72f8344bcf9b425e9fd022f0a9c5c2029812f1a4b00ba9f2a8ee504eb572

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