Malicious PDF — malware analysis report

Static analysis result for SHA-256 712d357ecdf0cd1e…

MALICIOUS

PDF

41.3 KB Created: 2021-05-10 16:49:25 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-02
MD5: 4c47a5abb8eeadb5baf9b187ed9dedc3 SHA-1: 3231aab4946d04ffbf52dad06172861a2f47980a SHA-256: 712d357ecdf0cd1e4578ca2e89b43b74c0bf047dd711242e7e4332ee150c564f
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF document was flagged as malicious by an ML classifier. 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 0.9971

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.
  • 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.
  • 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/406889139/coin-master-hack-ios-reddit-game-hack PDF link annotation
    • https://cuc.ac.cr/userfiles/files/how-to-get-free-robux-by-playing-games_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/coin-master-daily-free-spins-link-2021_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/free-roblox-printables_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/free-spins-coins-coin-master_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/free-flip-master-coins_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/daily-free-spins-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/how-to-hack-and-get-free-robux_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/play-coin-master_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/hack-the-game-coin-master_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/tower-of-hell-roblox-hack_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/krnl-roblox_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/coin-master-free-spins-links-app_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/how-to-get-free-robux-fast-and-easy_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/free-robux-only-username_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/google-coin-master-free-spins_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/coin-master-play-online-free_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/coin-master-free-coin-hack_GM406889139.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/free-roblox-accounts-with-robux-2021_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/how-to-get-a-refund-on-roblox-2021_GM431946152.pdfIn PDF document text
    • https://cuc.ac.cr/userfiles/files/how-do-you-earn-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_003_off00004729.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4729 24976 bytes
SHA-256: 1073a9612bf36d7744c547da5121416bc74b393349b1e5a6573d177219f597d3
font_01_sfnt_off0000801d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x801D 17888 bytes
SHA-256: f6db0d5ce37e689a46ceb71450432421ac9d8148bbd676fee9db03c905ab63a7

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