Malicious PDF — malware analysis report

Static analysis result for SHA-256 99b4c427375fb591…

MALICIOUS

PDF

44.7 KB Created: 2021-06-03 11:49:07 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 23b8caee5777d1860a9ed987a1efe855 SHA-1: e978b8bafc9b4870485803b6ebe7a4e07ab3b061 SHA-256: 99b4c427375fb591b71efe86c0de8e6549e391ca1bc435c689f8daa55f1b2af5
280 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1566.002 Spearphishing Link T1204.002 Malicious Link

This PDF document employs a lure of 'Free Robux' and impersonates Microsoft to trick users into clicking a malicious link. The link leads to a known malicious redirector infrastructure that presents a fake CAPTCHA or MFA prompt, likely to harvest credentials or session tokens. The document also contains numerous other links to potentially malicious PDF files hosted on a similar domain, suggesting a broader campaign of phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

Heuristics 7

  • 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.
  • 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
  • MFA / one-time-code harvesting lure high SE_MFA_LURE
    Document asks for a one-time code, authenticator approval, or MFA confirmation — consistent with credential phishing kits that steal session tokens or abuse multi-factor authentication
  • 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.online/app/431946152/free-robux-scams-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
  • 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.online/app/431946152/free-robux-scams-game-hack In PDF document text
    • http://library.stieyapan.ac.id/repository/coin-master-free-spins-glitch_GM406889139.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/how-to-hack-roblox-2021_GM431946152.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/coin-master-online-hack-2021_GM406889139.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/coin-master-hack-without-verification-or-downloading-apps_GM406889139.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/pokemon-go-free-account_GM1094591345.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/coin-master-game-free-download-for-pc_GM406889139.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/how-do-you-get-free-robux_GM431946152.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/toolbox-for-minecraft-pe-mod-apk_GM479516143.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/minecraft-education-free_GM479516143.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/free-robux-glitch_GM431946152.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/robux-earning-websites_GM431946152.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/archery-master-3d-apk-and-mod-free-download-unlimited-coins_GM406889139.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/hack-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/coin-master-hack-download-ios_GM406889139.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/minecraft-hack-app_GM479516143.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/roblox-got-talent-piano-hack_GM431946152.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/roblox-arsenal-hack_GM431946152.pdfIn PDF document text
    • http://library.stieyapan.ac.id//repository/how-to-make-a-minecraft-server-for-free_GM479516143.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/free-robux-not-a-scam_GM431946152.pdfIn PDF document text
    • http://library.stieyapan.ac.id/repository/free-robux-just-enter-username_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_004_off000051cf.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x51CF 25480 bytes
SHA-256: 0e638ced023e7574b17d8ffab16fee61719dd2713d923c6ea354d948b4163f34
font_01_sfnt_off00008bb3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8BB3 18500 bytes
SHA-256: f6eebadb3de4af7ab0205057cc55fc1daf9397692da1370c2a19d2d749ad11f1

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