Malicious PDF — malware analysis report

Static analysis result for SHA-256 e4cb7d436d3fad5e…

MALICIOUS

PDF

46.3 KB Created: 2021-06-09 06:12:09 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-23
MD5: eedd50d35b6971760c90437f98d1cae7 SHA-1: 318f4c5ce1756c9ec903987efd926a4d2f412c54 SHA-256: e4cb7d436d3fad5e71e43c78ac111e745afa8eda18967bb55169ff1bb9c3d6f6
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 0.9748

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/how-to-get-robux-for-free-xbox-one-game-hack PDF link annotation
    • http://perpus.masda.ac.id/repository/easy-robux-today_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/minecraft-hacks-pc_GM479516143.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/coin-master-rare-cards-hack_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/how-to-get-free-robux-youtube_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id//repository/martian-lettuce-coin-master-free_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/coin-master-free-spins-no-human-verification_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/minecraft-book-collection_GM479516143.pdfIn PDF document text
    • http://perpus.masda.ac.id//repository/free-roblox-gift-card-codes-2021-unused_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id//repository/coin-master-free-spins-2021-apk_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id//repository/how-to-get-free-spins-on-coin-master-without-verification_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id//repository/coin-master-free-spins-twitter_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/free-robux-group-payouts_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/how-to-get-free-robux-games_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/op-rewards-robux_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id//repository/how-to-get-free-spins-on-coin-master-without-waiting_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id//repository/free-spins-on-coin-master-2021-ios_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/how-to-get-more-spins-on-coin-master-hack_GM406889139.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/free-robux-by-watching-ads_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/roblox-troll-shirt-free_GM431946152.pdfIn PDF document text
    • http://perpus.masda.ac.id/repository/free-roblox-generator-for-roblox_GM431946152.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_off0000500f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x500F 24372 bytes
SHA-256: 096bd995b050f722eb560046a167e818b1e1f1275e453101cfffa2e7459073b3
font_01_sfnt_off000087ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x87EC 2952 bytes
SHA-256: 77d4b4da643075266290c2bd4ff3cde7a1edb1aa66f41fd247738531d2893d48
font_02_sfnt_off0000922c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x922C 18280 bytes
SHA-256: 4ab76c2d1b4479eeef8e9c8c7a38774356fd41fb56d42ce2f23cdbab9bbddf40

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