Malicious PDF — malware analysis report

Static analysis result for SHA-256 b195c6ce3e295de7…

MALICIOUS

PDF

44.3 KB Created: 2021-05-16 06:41:36 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-05
MD5: ec19b8647efd8af9a082169c71c7f841 SHA-1: b52a9ddfb459708aa57e46d50bfb7e667681b888 SHA-256: b195c6ce3e295de76839ec6231c269b02d2c60fe9f4a6d462ddbd47e5e89a86d
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 0.9980

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.xyz/app/431946152/free-robux-no-human-verification-2021-game-hack PDF link annotation
    • http://bemviverclin.com.br/images/how-to-earn-robux-for-free-2021_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/free-robux-no-gift-card_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/how-to-get-free-robux-2021_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/como-hackear-coin-master-espaol_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/wurst-115-2_GM479516143.pdfIn PDF document text
    • http://bemviverclin.com.br/images/claimrbx-free-robux_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/how-many-villages-are-in-coin-master_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/coin-master-hack-spins-apk_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/free-robux-generator-no-verification-2021_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/coin-master-free-spins-link-blogspot-april-2021_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/coin-master-hack-september-2021_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/free-coins-and-spins-link-for-coin-master_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/is-minecraft-free-on-computer_GM479516143.pdfIn PDF document text
    • http://bemviverclin.com.br/images/roblox-help-free-robux_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/how-to-get-free-robux-on-chromebook_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/free-robux-no-human-verification-or-survey-or-download-2021_GM431946152.pdfIn PDF document text
    • http://bemviverclin.com.br/images/coin-master-links-2021_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/coin-master-free-spins-link-deutsch-ios_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/coin-master-free-coins-facebook_GM406889139.pdfIn PDF document text
    • http://bemviverclin.com.br/images/rewards-roblox_GM431946152.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_003_off00004a01.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4A01 26992 bytes
SHA-256: f68a798484c7c033b67e4b5ebaa5a716a4b3bb5a0519b565731068f13e9d44c9
font_01_sfnt_off000087ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x87ED 19260 bytes
SHA-256: 6a9b2633b50d097f4b127a07737bc979a0fc1726e0f4efc9f53c1be2676c3116

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