Malicious PDF — malware analysis report

Static analysis result for SHA-256 51d6109e5247a534…

MALICIOUS

PDF

46.0 KB Created: 2021-05-11 06:25:35 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-22
MD5: 1d84697cfbda39c13a7a43f2da69e507 SHA-1: 6d24cd474cd7cc7a2d8d69c31104535f185d944b SHA-256: 51d6109e5247a534401ccda8d7b2f40343bb24aa0ed2bf647c058bc2a86dc64e
182 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by an ML classifier. It uses brand-impersonation credential phishing. 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 6

  • 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.
  • Brand-impersonation credential phishing lure high SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: call-to-action link host does not match the impersonated brand: https://netcdn.xyz/app/431946152/how-to-make-roblox-clothes-for-free-game-hack.
  • 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/431946152/how-to-make-roblox-clothes-for-free-game-hack PDF link annotation
    • https://lesegais.ru/images/can-you-get-free-robux-on-roblox_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/google-how-do-you-get-free-robux_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/free-robux-no-human-verification-generator_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/how-to-hack-a-roblox-account-easy_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/coin-master-free-daily-spins-today_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/free-spins-on-coin-master-generator_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/coin-master-free-spin-group_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/how-to-get-to-village-3-in-coin-master_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/windows-10-minecraft-hacks_GM479516143.pdfIn PDF document text
    • https://lesegais.ru/images/coin-master-hack-spin-generator-tool_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/get-free-robux-generator_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/robux-offers_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/today-coin-master-spin-free_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/coin-master-free-2021-spin-link-today_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/is-minecraft-free-on-xbox_GM479516143.pdfIn PDF document text
    • https://lesegais.ru/images/coin-master-free-spins-2021_GM406889139.pdfIn PDF document text
    • https://lesegais.ru/images/earn-free-robux-for-roblox_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/can-you-give-me-free-robux_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/free-roblox-accounts-with-robux-that-work-not-banned_GM431946152.pdfIn PDF document text
    • https://lesegais.ru/images/free-spin-coin-master-link-2021_GM406889139.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_003_off00004d6f.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4D6F 28828 bytes
SHA-256: 3a7563a12eb3703bfa26e915e140fced0b9083cfc66387c7604e280c001ff532
font_01_sfnt_off00008fcb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8FCB 18976 bytes
SHA-256: 75869b94c2b17b25dac59f0b0f7f9ff270f85e9e7170da1a335b6396ed3bda83

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