Malicious PDF — malware analysis report

Static analysis result for SHA-256 881af42fc01a321b…

MALICIOUS

PDF

34.7 KB Created: 2021-07-05 17:34:19 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-24
MD5: 85e403e53ae7f0dc5c92cf04d4fec345 SHA-1: f6cb23bbd8cd004ee2b7cacd1ce814564ffaab9b SHA-256: 881af42fc01a321b1766874b3517ca501ac8354b4f6f1b6044700cb19ba406f4
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 0.9980

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 http://netcdn.tw/app/431946152/roblox-hacks-and-cheats-that-work-game-hack PDF link annotation
    • https://bioscience.kyst.com.tw/image/data/files/join-this-group-for-free-robux_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/robux-free-gift-card_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/coin-master-hacks-to-get-spins_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/free-roblox-account-username-and-password_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/instalar-hacks-para-counter-blox-roblox-offensive-en-espaol_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/free-spins-coin-master-app_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/free-coin-master-s_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/how-to-get-free-robux-easy_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/coin-master-for-pc-free-download_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/roblox-change-character-free_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/is-there-a-legal-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/coin-master-new-cards-hack_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/where-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/how-do-i-get-free-robux-with-in-24-hours_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/coin-master-free-daily-spins-and-coins_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/free-spin-coin-master-apk_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/roblox-diary-of-a-noob-download-prison-life-free_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/coin-master-coin-hack_GM406889139.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/free-robux-scams_GM431946152.pdfIn PDF document text
    • https://bioscience.kyst.com.tw/image/data/files/www-free-robux-com_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00003270.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x3270 21728 bytes
SHA-256: 8e198515e1dc48980222d2610739236449f67c6f34f724ea12607b07b0961e5e
font_01_sfnt_off00006243.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6243 19112 bytes
SHA-256: aaedec24038a60c0c8befcc7442e87e4a706557dfac0a5a5ef9e2814070fcd62

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