Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a66a1cbe1b25feb…

MALICIOUS

PDF

34.5 KB Created: 2021-07-05 20:42:34 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-01
MD5: ef6b0fd4295ea255937175e7b4440ab3 SHA-1: e029cf5b9ebd41f6390c195fea44ac41f84eec80 SHA-256: 8a66a1cbe1b25febc3f2507767ca07d6e201d38faeb3b4451e3583913f69bc98
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF document was flagged as malicious by an ML classifier. 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 0.9980

Heuristics 5

  • 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.
  • 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 http://netcdn.tw/app/406889139/coin-master-34-4-hack-game-hack PDF link annotation
    • http://www.bestbist.com/assets/uploads/pages/files/get-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/coin-master-332-apk-free-download_GM406889139.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/minecraft-classic-free_GM479516143.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/free-account-roblox-with-robux_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/robux-premium_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/free-minecraft-domain_GM479516143.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/is-minecraft-free-on-xbox-one_GM479516143.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/how-to-get-250-robux-for-free_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/free-roblox-pin-t-shirt_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/free-roblox-accounts-2021_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/free-spins-coin-master-no-survey_GM406889139.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/youtube-free-robux-promo-codes_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/roblox-group-free-robux_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/tryrbx-site-free-robux_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/how-to-make-free-robux_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/coin-master-free-spin-facebook-link_GM406889139.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/roblox-free-skin_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/how-to-get-free-minecraft-skins_GM479516143.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/free-robux-apps-that-work_GM431946152.pdfIn PDF document text
    • http://www.bestbist.com/assets/uploads/pages/files/daily-coin-master-free-spin-link_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_off000030e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x30E7 22808 bytes
SHA-256: dcdae08637f49dad52749520bd57f976ce9b4f1f69d01fe387b63572cdf29f78
font_01_sfnt_off00006411.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6411 18240 bytes
SHA-256: c6a603a236db465a7556ab6a5027bd55d5ce2b4fe35e46119782d363115cdd6f

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