Malicious PDF — malware analysis report

Static analysis result for SHA-256 91bbb92e8eb1590a…

MALICIOUS

PDF

34.8 KB Created: 2021-06-29 15:23:59 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-23
MD5: 875aa9c0436e8c75e8a1a4af9ccb7f92 SHA-1: 5fb98d09eb3c22ac73a39f3da74ec6bef92ac708 SHA-256: 91bbb92e8eb1590a14fafa51a54d596727a616cc9a5baec4544b7c871e6079ab
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple links designed to lure users with promises of game hacks and currency, directing them to a redirector URL. This redirector, in turn, points to a large number of SEO-optimized PDF files hosted on a separate domain, suggesting a link farm or traffic generation scheme. The ML classifier strongly supports the malicious nature of this PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • PDF links to a 'free generator / game hack' redirector critical 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. CRITICAL on its own: the /app/<id>/<slug>-game-hack path shape is unambiguous scam infra, and the host rotates so a host-list match can't be relied on.
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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
  • 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.co/app/431946152/eletric-state-roblox-fast-money-and-free-money-hack-game-hack In PDF document text
    • http://library.acehresearch.org/repository/coin-master-free-spins-and-coins-today_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/free-coin-master-spins-no-human-verification_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/free-spins-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/how-to-get-free-money-in-jailbreak-roblox_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/free-robux-promo-codes-wiki_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/roblox-toys-free-code-generator_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/coin-master-hack-tool-without-verification_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/coin-master-hack-app-2021_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/best-free-gun-models-for-roblox_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/free-minecraft-server-hosting_GM479516143.pdfIn PDF document text
    • http://library.acehresearch.org/repository/roblox-hack-no-human-verification-2021-ios_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/hacked-roblox-accounts-list_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/roblox-thats-free_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/robux-hacks-tay-take-off_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/minecraft-building-hacks_GM479516143.pdfIn PDF document text
    • http://library.acehresearch.org/repository/free-coins-coin-master-blog_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/coin-master-village-cost_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/how-to-hack-coin-master-with-root_GM406889139.pdfIn PDF document text
    • http://library.acehresearch.org/repository/fake-free-robux-place_GM431946152.pdfIn PDF document text
    • http://library.acehresearch.org/repository/how-to-fly-in-roblox-using-cheat-engine_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
font_00_sfnt_off000031cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x31CF 21664 bytes
SHA-256: 2c99c2577055fc952447b9621de4ee672ac3c2e1062995ad05820d6b50003ef9
font_01_sfnt_off0000618e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x618E 19596 bytes
SHA-256: 7e3e476ab0d11faf5bacf834054006e2e029fd0a7b5c02c4cd7eff50b9b1f98a

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