Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef643b7306696259…

MALICIOUS

PDF

44.4 KB Created: 2021-06-09 06:15:31 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-18
MD5: 3b19e35594d3f63f666fa78b1a3ea7c4 SHA-1: 80fa736fdb40b6db5b69f3279f73dbbe6dfca1e9 SHA-256: ef643b7306696259366c1af73fcbec08fbe626c57461c23e9d4d26a77d31456a
122 Risk Score

Malware Insights

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

The PDF document employs a lure related to 'free Robux' and displays a fake CAPTCHA to deceive users into clicking a link. This link, 'https://netcdn.tw/app/431946152/roblox-hack-how-to-get-free-robux-2021-game-hack', likely leads to a malicious site designed to exploit the user or deliver a secondary payload. The ML classifier strongly supports the malicious nature of this PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

Heuristics 5

  • 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.tw/app/431946152/roblox-hack-how-to-get-free-robux-2021-game-hack PDF link annotation
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/gold-card-coin-master-free_GM406889139.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/getrobux-now_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/coin-master-official-page_GM406889139.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/coin-master-free-spins-instagram_GM406889139.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/free-robux-android_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/free-robux-no-downloading-apps_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/free-robux-com-real_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/free-roblox-animations_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/roblox-comroblox_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/how-to-get-free-robux-without-verifying-2021_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/www-rbxhut-com_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/coin-master-hack-online_GM406889139.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/coin-master-free-spin-facebook-link_GM406889139.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/coin-master-hack-program_GM406889139.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/free-robux-easy_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/free-minecraft-account-and-password_GM479516143.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/minecraft-free-minecoins_GM479516143.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/complete-offers-for-robux_GM431946152.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/how-do-you-hack-for-2021000-coins-on-flip-master_GM406889139.pdfIn PDF document text
    • http://perpustakaan.kedokteran.ump.ac.id/index/repository/mcpe-hacks_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_004_off00005151.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5151 23992 bytes
SHA-256: 26bd4f364e10ce7f538a1bb4e2b0d3a10d71c9289535ee2f223d5e537eb4a90e
font_01_sfnt_off00008811.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8811 19156 bytes
SHA-256: 6654370761e734524a43ba51cd5ad56747be32099aef9815bc118600966202a1

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