Malicious PDF — malware analysis report

Static analysis result for SHA-256 a39bfb8304ee303a…

MALICIOUS

PDF

45.1 KB Created: 2021-05-20 02:49:48 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-16
MD5: 92b4afb601cd4f19258ae484778ce074 SHA-1: 529feddd720d7ffe5fe3d3be54222a43eb1c4cc4 SHA-256: a39bfb8304ee303a63d91cd503fa24827b85aabd3b5fd1715f33a423c19d1eeb
142 Risk Score

Malware Insights

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

The PDF document contains a fake CAPTCHA lure, designed to trick users into interacting with malicious links. It also features a large number of external links, many pointing to PDF files, suggesting a link farm or SEO manipulation tactic. The ML classifier also flagged this PDF as malicious with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9632

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.
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • 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-daily-free-spins-link-today-blogspot-game-hack PDF link annotation
    • http://sbm-nn.ru/images/coin-master-hack-quora_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-robux-accounts-2021_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-robux-gift-card_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-to-get-free-minecoins-in-minecraft_GM479516143.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-do-i-get-free-robux-on-roblox_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-roblox-card_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-robux-no-human-verification-generator_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-to-get-free-spins-for-coin-master_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-to-get-free-roblox_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-free-spin-today-2021_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-robux-not-a-scam_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-mod-apk-latest-hack-with-unlimited-free-spins_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-hack-for-android_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-links-for-today_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/apps-for-free-spins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/pubg-uc-buy-in-pakistan-jazz-cash_GM1330123889.pdfIn PDF document text
    • http://sbm-nn.ru/images/get-free-robux-without-doing-anything_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-spin-hack-apk_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-robux-codes-2021_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/robux-websites-that-work_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_off00004917.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4917 24476 bytes
SHA-256: 86e2514138b2eecc1da3d3ac8553d9553cf781968a2a4a89dc2bd063bfb201fa
font_01_sfnt_off00008122.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8122 2840 bytes
SHA-256: 3fb127b764b9d10f5525bc4de5ec8316de704409ccb0cf21cff3ad8a30d11676
font_02_sfnt_off00008ad3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8AD3 19156 bytes
SHA-256: c6e44e2d9e69c9765448dadb9ef0e8fe599e3907f261bb989cdf753410e037ff

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