Malicious PDF — malware analysis report

Static analysis result for SHA-256 51814c96a20b1b9b…

MALICIOUS

PDF

47.8 KB Created: 2021-06-03 10:01:31 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-01
MD5: dda7a09e973fbbb8b290f56163bb6c60 SHA-1: 1f38a52841d55877485ac5913773ff5fe5ebb866 SHA-256: 51814c96a20b1b9b53e1ffd3745bc19c6aff02fcdba94567d4ca63996adecd57
182 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by an ML classifier. It uses a fake-CAPTCHA lure. The file embeds a large number of external links characteristic of an SEO link farm, routes users through malicious redirector infrastructure and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9769

Heuristics 6

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • PDF links to a 'free generator / game hack' redirector high 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.
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • 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
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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/431946152/free-roblox-templates-game-hack PDF link annotation
    • http://pustaka.bbppketindan.info//repository/pubg-uc-rate-in-pakistan_GM1330123889.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/roblox-free-exploits_GM431946152.pdfIn PDF document text
    • http://pustaka.bbppketindan.info//repository/how-to-get-free-roebucks_GM431946152.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/blogspot-coin-master-free-spins_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info//repository/coin-master-hack-apk-link_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info//repository/free-spins-coin-master-haktuts_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info//repository/coin-master-free-spins-daily_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/hack-spin-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/minecraft-bedrock-edition-pc-free_GM479516143.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/coin-master-hack-app-2021_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/cone-master_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info//repository/coin-master-free-daily-rewards_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/coin-master-link-today_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/free-spins-on-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/minecraft-xbox-one-free_GM479516143.pdfIn PDF document text
    • http://pustaka.bbppketindan.info//repository/coin-master-free-link-spin_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/roblox-rewards-robux_GM431946152.pdfIn PDF document text
    • http://pustaka.bbppketindan.info//repository/free-coin-app_GM406889139.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/free-roblox-accounts-2021-with-robux_GM431946152.pdfIn PDF document text
    • http://pustaka.bbppketindan.info/repository/coin-master-free-cards-link-2021-today_GM406889139.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_off00004d52.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4D52 25952 bytes
SHA-256: 8f790ea00a6f71273b48e3717490561604f9284b126b0272e638f14f42c0624b
font_01_sfnt_off000089b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x89B9 5696 bytes
SHA-256: 450e3ee45915afe13702bf1d587eb8b9ad88a8d2113419ac9f2fd116a828e139
font_02_sfnt_off000096ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x96CA 18716 bytes
SHA-256: bf2cc55c1544d3a32bf4b8d9dd067a1dc9fa2bd8ba88e470198e88e73129adbc

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