Malicious PDF — malware analysis report

Static analysis result for SHA-256 647960a08cdc890c…

MALICIOUS

PDF

44.3 KB Created: 2021-06-03 07:52:04 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-22
MD5: 49d42f8ce668770cf3d4b2aa94a442d6 SHA-1: 67fd2b6610bb6b361119700ea08671ea74cba567 SHA-256: 647960a08cdc890c1f65dad26fb1e2eb17f1d67a4af27c5068ddcfdc76b473f4
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 0.9865

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.online/app/406889139/coin-master-free-spin-and-coins-links-home-game-hack PDF link annotation
    • http://www.6636.com.tw/ad6636/upload/files/coin-master-daily-free-rewards_GM406889139.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/daily-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/coin-master-free-spins-generator_GM406889139.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/free-spin-link-for-coin-master-game_GM406889139.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/how-to-get-free-hair-on-roblox-2021_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/is-there-a-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/free-minecraft-maps-pe_GM479516143.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/coin-master-hack-tool-v1-9-download_GM406889139.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/wahoo-gaming-co-free-robux_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/free-robux-obby-2021_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/coin-master-free-link-2021_GM406889139.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/www-robux_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/how-to-create-a-minecraft-server-for-free_GM479516143.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/free-robux-hack-no-human-verification_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/coin-master-daily-gift-free-spins-and-coins-link_GM406889139.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/how-to-hack-people-on-roblox_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/free-tiktok-fans-no-verification_GM835599320.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/how-to-change-your-roblox-username-for-free-2021_GM431946152.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/how-to-get-minecraft-for-free-on-xbox_GM479516143.pdfIn PDF document text
    • http://www.6636.com.tw/ad6636/upload/files/roblox-group-free-robux_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_004_off00005201.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5201 24764 bytes
SHA-256: e21f7720652bbe79dd655a2582d9cd09fca21fc5bbbd3bbdd4be224ac4d0edfe
font_01_sfnt_off00008a0c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8A0C 18492 bytes
SHA-256: c6f1255b5246b10a2381080087e328848ca3d63cb104c3d5d5a1d34eeed5229c

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