Malicious PDF — malware analysis report

Static analysis result for SHA-256 843a8b19aadad844…

MALICIOUS

PDF

44.6 KB Created: 2021-05-14 18:00:10 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-27
MD5: cfabe4c9742ec20365c327044a2fc0ae SHA-1: 6ed9067ad788657d8ec1f03fe2fb65b2fed88798 SHA-256: 843a8b19aadad844db23d950fb49cf4db46de21f57ea7b13a0273f49287fd571
102 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of external links, many of which are SEO-optimized and point to other PDFs, indicating a link farm designed to drive traffic. The document body and extracted URLs suggest a lure related to free spins for Coin Master or Robux, a common tactic for phishing or malware distribution. The presence of a 'download button' heuristic further supports the malicious intent of encouraging user interaction with potentially harmful links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9632

Heuristics 4

  • 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
  • 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-spins-link-2021-no-verification-game-hack PDF link annotation
    • http://centr-expert.su/images/robuxhub-net_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/free-robux-games-that-actually-work-2021_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/apps-for-free-spins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/how-to-get-free-spins-on-coin-master-facebook_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/get-free-robux-no-verification_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/coin-master-hack-download-ios_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/how-to-hack-into-someones-roblox-account_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/free-spins-in-coin-master-without-human-verification_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/no-robux_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/how-to-get-free-robux-easy_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/coin-master-unlimited-spin-apk-free-download_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/coin-master-hack-mod-apk-2021_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/roblox-system_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/minecraft-hacks-wurst_GM479516143.pdfIn PDF document text
    • http://centr-expert.su/images/freespinandcoinblogspot-com-2021-11-coinmasterfreespins_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/free-coins-and-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://centr-expert.su/images/minecraft-launcher-free_GM479516143.pdfIn PDF document text
    • http://centr-expert.su/images/free-robux-websites-that-work_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/roblox-free-clothes-girl_GM431946152.pdfIn PDF document text
    • http://centr-expert.su/images/free-robux-codes-no-verification-2021_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off000046c8.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x46C8 25128 bytes
SHA-256: 619356774f44a1b4c78287dd73adfb2e51c5a277de459d060ed31361c08e4dea
font_01_sfnt_off0000808a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x808A 2880 bytes
SHA-256: 10d025f04f706eb71cdda4f99784df1b9ccb52e48080e43095e0398eaef6f132
font_02_sfnt_off00008a74.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8A74 18592 bytes
SHA-256: fb80ad8e35183f753bf91a402d0f68d299ceb73e5cb9a5d171aabc3029406e01

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