Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8fa593c9668ac73…

MALICIOUS

PDF

44.9 KB Created: 2021-05-14 09:57:02 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-24
MD5: ddfebe595a1b462443ca727bfb37efe0 SHA-1: 20fa84b4778609e6527f9b6a8ea3c9db731697b9 SHA-256: f8fa593c9668ac736a79ce2353ee9a00f9812fce1174944ff14622938b77e1d7
182 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

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 0.9980

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 link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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-free-2021-spin-link-today-game-hack PDF link annotation
    • https://cursocejas.com.br/imagens/userfiles/files/free-robux-no-verification-no-survey_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/roblox-free-accessories_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/free-robux-generator-no-survey-no-download-no-human-verification_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/50-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/robux-hack-free-robux_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/coin-master-hack-cheat-generator-d_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/coin-master-15-free-spin-link-of-last-5-days_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/is-there-any-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/coin-master-free-link-spin_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/free-robux-websites-that-actually-work_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/how-to-hack-in-roblox-prison-life_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/how-to-hack-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/free-robux-apps-that-work_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/how-to-make-my-own-coin-master-cards-hack_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/freespinandcoinblogspotcom-2021-11-coinmasterfreespinandcoinlinkshtml_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/coin-master-hack-spins-2021_GM406889139.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/free-robux-com-roblox_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/is-minecraft-free-on-mac_GM479516143.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/robux-survey_GM431946152.pdfIn PDF document text
    • https://cursocejas.com.br/imagens/userfiles/files/i-didnt-get-my-free-spins-in-coin-master_GM406889139.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_off00004a90.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4A90 28416 bytes
SHA-256: 50516440fbd7545d8244107579ef39944765a154c065542ca489dd1d9f890096
font_01_sfnt_off00008b9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8B9D 18812 bytes
SHA-256: 7f624a4da072bd42e21ae13ab081f80009d2c012a41e181bc6a40f65c236f9bb

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