Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b86b85990d8c24d…

MALICIOUS

PDF

48.5 KB Created: 2021-06-03 10:29:58 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 035b2a3b85ab5741f9b8314dcf2ca5ec SHA-1: 671d9c93acb4c2d2c69ab6a2a48d9f6397d93a3f SHA-256: 4b86b85990d8c24db93d4a0e091b28aed0405c4eb7c0831ea63e7087f07a0387
182 Risk Score

Malware Insights

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

This PDF document employs a fake CAPTCHA and brand impersonation lure, specifically targeting Roblox users with "free Robux" offers, while impersonating Amazon. It contains a large number of external links, many pointing to PDF files hosted on `lib-stie.yai.ac.id`, suggesting a link farm designed to redirect users to malicious or phishing sites. The primary malicious URL identified is `https://netcdn.online/app/431946152/roblox-hack-free-robux-and-tix-no-survey-game-hack`.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9796

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.
  • 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
  • Brand-impersonation credential phishing lure high SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: call-to-action link host does not match the impersonated brand: https://netcdn.online/app/431946152/roblox-hack-free-robux-and-tix-no-survey-game-hack.
  • 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/roblox-hack-free-robux-and-tix-no-survey-game-hack PDF link annotation
    • https://lib-stie.yai.ac.id/repository/free-robux-with-no-verification_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/coin-master-free-spins-link-june-2021_GM406889139.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/how-to-hack-roblox-accounts-for-robux_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/how-to-earn-robux-for-free-2021_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/robux-com-free-robux_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/get-free-robux-today_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/free-robux-sites-that-work_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/websites-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/rbx-free-robux_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/how-to-free-robux_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/coin-master-free-cards_GM406889139.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/coin-master-free-cards-link_GM406889139.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/easy-how-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/coin-master-hack-without-verification_GM406889139.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/is-there-any-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/pokemon-go-free-bundle_GM1094591345.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/free-robux-websites-that-actually-work-2021_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/coin-master-real-free-spins_GM406889139.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/free-robux-no-human-verification-no-survey_GM431946152.pdfIn PDF document text
    • https://lib-stie.yai.ac.id/repository/how-to-get-free-coins-in-coin-master_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
font_00_sfnt_off000053e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x53E9 25328 bytes
SHA-256: 4fe243679d508ae8ff50f8a4de26a60a4d889d91a1740ea294200b9d387627bd
font_01_sfnt_off00008eff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8EFF 2824 bytes
SHA-256: 955f67b406fbbec05d672b95b629f36b6c362c3b45d60943b9c93d3ef2276540
font_02_sfnt_off000098ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x98AD 19076 bytes
SHA-256: 727487423c912af2cc87b3cf8e098d8e1af03c480c07f60670d651340801b11b

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