Malicious PDF — malware analysis report

Static analysis result for SHA-256 d31d594977f76d82…

MALICIOUS

PDF

40.9 KB Created: 2021-05-17 22:31:51 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 3d10e197bd2d3bfeec12a185cc53c553 SHA-1: e0e54049a1851ce7158d4a0b7a6931264c8defda SHA-256: d31d594977f76d82d1d3aae8ee9d103d4ce2c56cb0bdead24043780cc7825a21
160 Risk Score

Malware Insights

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

The PDF contains multiple links to known malicious redirectors and lures users with promises of game hacks and free spins. The ML classifier also strongly indicated maliciousness. The primary attack vector appears to be social engineering to trick the user into visiting a malicious URL, likely leading to further malware download or exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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/406889139/coin-master-free-spins-reddit-game-hack In PDF document text
    • http://zercalo.org/images/coin-master-hack-tool-2021_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/moonactive-coin-master-free-spins-link_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/how-to-install-minecraft-for-free_GM479516143.pdfIn PDF document text
    • http://zercalo.org/images/coin-master-heaven-links_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/free-robux-discord-servers_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/how-to-hack-people-on-roblox_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/coin-master-links-2021_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/boku-no-roblox-hack_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/roblox-free-robux-no-verification_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/free-robux-quiz_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/i-got-hacked-on-roblox_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/cool-free-roblox-outfits_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/coin-master-free-download_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/free-spins-and-coins-coin-master_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/free-spins-coin-master-app-iphone_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/free-spins-and-coins-for-coin-master_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/pasos-para-hackear-coins-master_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/app-master_GM406889139.pdfIn PDF document text
    • http://zercalo.org/images/win-free-robux_GM431946152.pdfIn PDF document text
    • http://zercalo.org/images/what-is-a-minecraft-client_GM479516143.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_off000046b0.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x46B0 24348 bytes
SHA-256: aa9f7c5a430312fc1b13f81f5fc9e94db38f272c865e47acd4a45cb537b0db9c
font_01_sfnt_off00007e0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7E0D 18060 bytes
SHA-256: 4e5c9128e0a9fa60b92eedd1f31c2e3424560d9f599dff1a3da25a642fd73c7b

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