Malicious PDF — malware analysis report

Static analysis result for SHA-256 a6b73527b7070e02…

MALICIOUS

PDF

42.6 KB Created: 2021-05-16 04:25:59 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 654259e31ff5fa5f8fe4f8135c7f7193 SHA-1: 821e385da0a64481b4c574fb4c45e022dd779ad1 SHA-256: a6b73527b7070e02da832f2b5baf929fdb15e797a5f8a1e8d9f10526e5cf9b69
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a malicious link disguised as a 'free generator' or 'game hack' for Roblox, redirecting to known malicious infrastructure. The malformed stream length and ML classifier further indicate malicious intent. While no scripts were directly extracted, the PDF structure and embedded links suggest an attempt to exploit vulnerabilities or trick the user into downloading a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://netcdn.xyz/app/431946152/free-roblox-toys-game-hack In PDF document text
    • http://www.nielsen2u.dk/images/roblox-avatar-girl_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-robux-no-verification-2021-ios_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/coin-master-gameplay_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-robux-websites-no-human-verification_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/coin-master-free-spin-facebook-link_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/coin-master-unlimited-spin-hack-mod-apk_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-robux-reddit_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-robux-hack-generator_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/earn-free-robux-for-roblox_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/bux-life-free-robux_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/coin-master-free-stuff_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/coin-master-golden-card-hack_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-promo-codes-for-coin-master_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-spins-link-in-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-spins-coin-master-facebook_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/hack-coin-master-apk-32-download_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-robux-2021-no-human-verification_GM431946152.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/free-links-to-coin-master_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/today-coin-master-free-coins-link_GM406889139.pdfIn PDF document text
    • http://www.nielsen2u.dk/images/get-free-robux-today_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
stream_003_off00004928.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4928 26020 bytes
SHA-256: c1f41e6e43934cfe24e655ef7b99cea5c48c88393a7c92452a1082601639f367
font_01_sfnt_off000084a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x84A3 18128 bytes
SHA-256: ced59fa1f5966ac3cb16d2fbea4d1e317d998f5f31502ffb274740285f9cbd45

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