Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8ca81efe99f3a7d…

MALICIOUS

PDF

47.0 KB Created: 2021-06-03 12:28:52 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 7d2e189a2cfe28b1a649dff0faf9b879 SHA-1: 63891faac973e58a6e6ee9de2a50e27176d9b4ff SHA-256: a8ca81efe99f3a7d1622aa33685811726530c4a9e7658226a68fcfc04acffc13
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains multiple embedded URLs and a heuristic firing for an external URI, all pointing to sites offering game hacks and free in-game currency. The document body, though partially corrupted, includes references to 'Coin Master Daily Free Spin App' and a URL that likely serves as a download link for a malicious application. The ML classifier also flagged this PDF as malicious with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9769

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.online/app/406889139/coin-master-daily-free-spin-app-game-hack In PDF document text
    • https://ifef.es/ckfinder/userfiles/files/free-spin-app-for-coin-master_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/free-robux-hack-2021_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/free-robux-obby_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/how-do-i-get-minecraft-for-free_GM479516143.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/pubg-uc-2021_GM1330123889.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/roblox-robux-generator-no-human-verification_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/roblox-hack-scripts-pastebin_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/robux-free-co_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/robux-in_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/coin-master-apk_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/coin-master-cards-hack_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/where-can-i-get-free-spins-for-coin-master_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/coin-master-free-spins-and-coins-daily_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/free-spins-for-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/free-coin-master-spins-and-coins_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/free-robux-with-no-survey_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/haktuts-coin-master-free-spin-link_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/coin-master-free-coins-and-spins-link_GM406889139.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/roblox-free-robux-hack_GM431946152.pdfIn PDF document text
    • https://ifef.es/ckfinder/userfiles/files/how-to-hack-minecraft-pe_GM479516143.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_004_off000053af.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x53AF 24348 bytes
SHA-256: 995ea1e89884b82c8723bf94a69c5d209b3149da3821a20cad953c3fe31b3d09
font_01_sfnt_off00008b14.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8B14 2880 bytes
SHA-256: 10d025f04f706eb71cdda4f99784df1b9ccb52e48080e43095e0398eaef6f132
font_02_sfnt_off000094ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x94FF 18308 bytes
SHA-256: f9a3a46f76b0cae8a4d9bd0baf07f2a5aefd3f4554b846be65e0119e8f17791d

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