Malicious PDF — malware analysis report

Static analysis result for SHA-256 d18770797166ea54…

MALICIOUS

PDF

51.7 KB Created: 2021-06-09 08:49:57 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: 25fac5926e1ec715855514522873393d SHA-1: 85ee7b6fc0094a48f2c163d9caf00d383a26788b SHA-256: d18770797166ea54aff2ce7d984811cf30dfb6333ef39807d51fbd0fec4fced0
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 0.9464

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.tw/app/431946152/games-on-roblox-that-promise-you-free-robux-game-hack PDF link annotation
    • http://digilib-pps.unja.ac.id/repository/windows-10-minecraft-free-with-java_GM479516143.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/minecraft-apk-114-4_GM479516143.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/coin-master-daily-spins-and-coins_GM406889139.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/roblox-why-does-hacking-kick-you-from-server_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/coin-master-fan-page_GM406889139.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/how-to-get-100-robux-for-free_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/free-coins-for-coin-master_GM406889139.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/coin-master-hack-unlimited-spins-apk-download_GM406889139.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/free-robux-promo-codes-2021_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/how-to-get-free-roblox-money_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/best-minecraft-hacked-client_GM479516143.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/coin-master-free-coins-and-spins-online-tool_GM406889139.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/sites-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/how-do-you-get-free-robux-2021_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/collect-free-spins-for-coin-master_GM406889139.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/robux-generator-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/how-to-get-free-robux-easy-on-phone_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/free-robux-giveaway_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/free-robux-gen_GM431946152.pdfIn PDF document text
    • http://digilib-pps.unja.ac.id/repository/links-for-coin-master-free-spins_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_off00005423.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5423 30660 bytes
SHA-256: 7693906f6ca9f6b4ae95fd6b57f50ff863d30a25dad4e0d50349236e37e26ba7
font_01_sfnt_off00009b65.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9B65 2872 bytes
SHA-256: 5a38050e56bfed6ba013c4835499ae05f4b57b22e606c9172dd4bc2ae7fd1207
font_02_sfnt_off0000a521.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xA521 19280 bytes
SHA-256: e3e30d2459461e8ed36479cb5101ec57f508783c661ee5e6044cc2fdef606fd0

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