Malicious PDF — malware analysis report

Static analysis result for SHA-256 961a535dd0e48c53…

MALICIOUS

PDF

35.8 KB Created: 2021-07-04 13:19:57 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: 98bc6ec0a2e9d4eca451cff5d32bbf3e SHA-1: 7dc41825642f9c802c0d6f954b3b1998b99b31e9 SHA-256: 961a535dd0e48c532f5773502c14822e4ecd7bd28db203c6df5711c4228cead3
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/406889139/coin-master-free-spins-and-chips-game-hack PDF link annotation
    • http://ycstamping.com.tw/image/data/files/roblox-to-get-robux-hack_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/roblox-com-hack_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/free-robux-obby-youtube_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/link-for-free-coins-in-coin-master_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/coin-master-free-daily-spins_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/coin-master-free-spin-ml_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/bloxawards-com-earn-free-robux_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/hackear-roblox-cheat-engine_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/how-to-get-free-robux-without-downloading-apps_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/caught-my-girlfriend-cheating-on-me-roblox_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/cute-free-stuff-on-roblox_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/how-to-get-free-spins-and-coins-in-coin-master_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/coin-master-spin-hack_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/coin-master-hack-app-download-free_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/how-to-get-free-robux-and-tix-on-pc_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/how-to-get-free-robux-hack-ios_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/free-games-roblox-games_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/roblox-its-free_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/minecraft-bedrock-edition-download-pc-free_GM479516143.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/robux-earner_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_002_off000034ee.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x34EE 23084 bytes
SHA-256: 45522f342724dda841e63342a2c957af243d106afeba62e018e7a11a124c4a66
font_01_sfnt_off000068cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x68CB 18516 bytes
SHA-256: 36cad0d0240957eee0646312619cc21c77e0b88ed1bf9b3bf004f144e54c7458

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