Malicious PDF — malware analysis report

Static analysis result for SHA-256 81a39eccac983dd2…

MALICIOUS

PDF

34.9 KB Created: 2021-07-06 02:54:19 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 564e4b0be0e1b396d7c0142d8a7c651c SHA-1: ffe6be33546e55bd5ebd46c24b1c68c3d522ec24 SHA-256: 81a39eccac983dd293f50d67b91b50972617a3cc97ab78ef44627b307b0e5149
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains multiple links, including one to a known malicious redirector infrastructure at http://netcdn.tw/app/431946152/how-to-hack-roblox-accounts-for-robux-game-hack. This lure, combined with the 'free generator / game hack' theme, strongly suggests a phishing or scam attempt designed to lead users to malicious sites. No scripts were extracted, but the embedded URLs are the primary indicators of malicious intent.

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/how-to-hack-roblox-accounts-for-robux-game-hack In PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/roblox-free-stuff-obby_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/free-robux-websites-that-actually-work_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/roblox-mobile-hack_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/best-way-to-get-robux_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/free-coin-master-spins-blog_GM406889139.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/robux-for-offers_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/microsoft-rewards-robux_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/coin-master-free-spins-and-coins-blogspot_GM406889139.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/coin-master-app-free-download_GM406889139.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/free-robux-giveaway-live_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/get-robux-now_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/coin-master-golden-card-hack_GM406889139.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/flying-hacks-roblox_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/coin-master-free-spins-without-human-verification_GM406889139.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/coin-master-free-spins-link-today-ios_GM406889139.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/free-robux-without-verification-2021_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/coin-master-free-coins-link-march-2021_GM406889139.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/how-do-u-hack-roblox_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/how-to-get-free-robux-in-2021_GM431946152.pdfIn PDF document text
    • https://www.gulfautotools.com/uploaded_files/userfiles/files/free-shirt-templates-roblox_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_off0000301f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x301F 22524 bytes
SHA-256: 08818713f5d6448dd0bb6e1d1a288132774235c44225dc8959da5a907583ee39
font_01_sfnt_off000062c7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x62C7 19228 bytes
SHA-256: c30d944de0a6baf9276c4865844fcb990da37fa04730b451441052e57c665125

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