Malicious PDF — malware analysis report

Static analysis result for SHA-256 bc73f6ac63ce6cab…

MALICIOUS

PDF

44.6 KB Created: 2021-06-11 00:20:44 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7)
MD5: 4049c7901f0faad664e20efdca453690 SHA-1: f50cf7d67eddc465d71a0753a8d2b1a7548a1f58 SHA-256: bc73f6ac63ce6cab2901503ebdf9592156ea19f6316cda16bd93f89eb96a2084
142 Risk Score

Malware Insights

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

The PDF document contains a fake CAPTCHA lure, aiming to trick users into clicking a link. This is supported by the 'SE_FAKE_CAPTCHA' heuristic and the presence of external URLs, including one pointing to 'cheats-to-get-robux-on-roblox'. The document's structure and numerous linked PDFs suggest a link farm designed to redirect users to potentially malicious content or downloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

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.
  • 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/cheats-to-get-robux-on-roblox-2021-game-hack
    • https://lib.unitri.ac.id//repository/free-robux-no-human-verification-generator_GM431946152.pdf
    • https://lib.unitri.ac.id/repository/free-robux-generator-2021-no-human-verification-or-survey_GM431946152.pdf
    • https://lib.unitri.ac.id//repository/how-to-get-free-pet-food-in-coin-master_GM406889139.pdf
    • https://lib.unitri.ac.id/repository/how-to-downgrade-minecraft-pe_GM479516143.pdf
    • https://lib.unitri.ac.id//repository/latest-free-spin-coin-master-daily_GM406889139.pdf
    • https://lib.unitri.ac.id/repository/how-to-get-minecraft-pocket-edition-for-free_GM479516143.pdf
    • https://lib.unitri.ac.id/repository/coin-master-hack-no-verification-ios_GM406889139.pdf
    • https://lib.unitri.ac.id//repository/i-cant-get-free-spins-coin-master_GM406889139.pdf
    • https://lib.unitri.ac.id//repository/free-robux-games-that-actually-work_GM431946152.pdf
    • https://lib.unitri.ac.id/repository/roblox-fun-robux_GM431946152.pdf
    • https://lib.unitri.ac.id//repository/free-spins-coin-master-2021_GM406889139.pdf
    • https://lib.unitri.ac.id/repository/roblox-rewards-robux_GM431946152.pdf
    • https://lib.unitri.ac.id//repository/free-robux-please_GM431946152.pdf
    • https://lib.unitri.ac.id/repository/how-to-get-free-robux-2021-no-human-verification_GM431946152.pdf
    • https://lib.unitri.ac.id//repository/how-to-get-minecraft-for-free-on-ipad_GM479516143.pdf
    • https://lib.unitri.ac.id//repository/minecraft-hax-download-no-virus_GM479516143.pdf
    • https://lib.unitri.ac.id/repository/minecraft-hacker-mask_GM479516143.pdf
    • https://lib.unitri.ac.id/repository/can-you-play-minecraft-for-free_GM479516143.pdf
    • https://lib.unitri.ac.id/repository/oprewards-login_GM431946152.pdf
    • https://lib.unitri.ac.id/repository/roblox-fly-hack-2021_GM431946152.pdf
    • http://en.wikipedia.org/wiki/MIT_License

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off00005296.bin
2f1d87fad06e7d43ef2c79f3d4cc0af5a20018ac7a4445226b4d0410c084039c		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5296 24328 bytes
font_01_sfnt_off000089f3.bin
7c5a8d2459f7e084f41cc70fcf6c12f10b0f20e5ba028b2ffee96b7d6008655e		 pdf-font-stream PDF embedded font (sfnt) at offset 0x89F3 18824 bytes

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