Malicious PDF — malware analysis report

Static analysis result for SHA-256 51b7a7761bd027c3…

MALICIOUS

PDF

33.9 KB Created: 2021-07-05 18:56:15 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 0d503061b72b86bd9cd86f3ddbf4790a SHA-1: e84af22786c1c00441984ae3302bd7e51acff54b SHA-256: 51b7a7761bd027c3250cbd29b2c88f3a408d9366e2355d42a509ae74d8bbf08a
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains multiple links to known malicious redirectors and lures users with promises of free game currency like 'Robux'. The primary malicious URL identified is http://netcdn.tw/app/431946152/roblox-robux-game-hack. While no scripts were explicitly extracted, the PDF structure and heuristic firings strongly indicate a social engineering attack designed to lead users to potentially harmful content or further malware downloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 http://netcdn.tw/app/431946152/roblox-robux-game-hack In PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/free-robux-that-actually-works_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/hack-para-roblox-dragon-ball-rage_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/minecraft-java-free-trial_GM479516143.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/easy-ways-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/houe-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/free-robux-websites-no-human-verification_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/minecraft-pe-015-0-apk-free-download_GM479516143.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/pubg-uc-quiz_GM1330123889.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/rb-robux-unlimited-hack_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/free-minecraft-severs_GM479516143.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/inf-robux-hack_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/minecraft-hacker-skin_GM479516143.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/free-robux-without-human-verification-website_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/robux-free-2021_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/robux-hack-2021_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/coin-master-free-items_GM406889139.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/robux-generator-no-verification-2021_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/how-to-change-username-on-roblox-for-free_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/free-robux-earn_GM431946152.pdfIn PDF document text
    • http://stikgiamakassar.ac.id/digilib/repository/free-spins-coin-master-links-no-human-verification_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
font_00_sfnt_off00002df6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2DF6 22540 bytes
SHA-256: 95a0037b8282233f3b67336ba0b1b90ab8333080c81df73743d03f7ec90678ab
font_01_sfnt_off000060b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x60B5 18628 bytes
SHA-256: 91fe40ca7b1c63e097b3ed98f551f0053b3fa477182f2dddb1f8374deacdf7be

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