Malicious PDF — malware analysis report

Static analysis result for SHA-256 d400fa1cbe72193f…

MALICIOUS

PDF

43.7 KB Created: 2021-06-03 05:12:06 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 8cba89feaa97a3ecb488b075958bcc45 SHA-1: 0c6fbcd3b63d987e98d8d5547690ff56948397dc SHA-256: d400fa1cbe72193f481e7f2647d1f9af7ee737330b0a1da173964598aa86e1a9
240 Risk Score

Malware Insights

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

The PDF document contains multiple links to malicious redirectors and impersonates Microsoft to lure users into clicking on a fake CAPTCHA. The primary lure is a 'free generator / game hack' which leads to a fake CAPTCHA page, likely intended to trick users into executing commands or performing actions that lead to further compromise. No scripts were extracted, but the embedded links and the fake CAPTCHA heuristic strongly suggest a credential phishing or malware delivery attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

Heuristics 6

  • 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
  • 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/roblox-fun-com-free-robux-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/roblox-fun-com-free-robux-game-hack In PDF document text
    • https://mbbs.hr/files/free-unlimited-coins-for-coin-master_GM406889139.pdfIn PDF document text
    • http://mbbs.hr/files/microsoft-bing-free-robux_GM431946152.pdfIn PDF document text
    • https://mbbs.hr/files/roblox-mobile-hack_GM431946152.pdfIn PDF document text
    • https://mbbs.hr/files/how-to-get-creative-mode-in-minecraft-server-hack_GM479516143.pdfIn PDF document text
    • http://mbbs.hr/files/free-roblox-girl-clothes_GM431946152.pdfIn PDF document text
    • https://mbbs.hr/files/how-to-earn-robux-for-free-2021_GM431946152.pdfIn PDF document text
    • http://mbbs.hr/files/free-robux-no-verification-2021_GM431946152.pdfIn PDF document text
    • http://mbbs.hr/files/coin-master-spin-free_GM406889139.pdfIn PDF document text
    • http://mbbs.hr/files/how-to-make-a-minecraft-server-for-free-java_GM479516143.pdfIn PDF document text
    • http://mbbs.hr/files/moonactive-coin-master-free-spins_GM406889139.pdfIn PDF document text
    • http://mbbs.hr/files/rbxoffers-com-free-robux_GM431946152.pdfIn PDF document text
    • http://mbbs.hr/files/do-you-get-minecraft-windows-10-for-free_GM479516143.pdfIn PDF document text
    • https://mbbs.hr/files/abd-roblox_GM431946152.pdfIn PDF document text
    • http://mbbs.hr/files/where-can-i-get-free-spins-for-coin-master_GM406889139.pdfIn PDF document text
    • http://mbbs.hr/files/how-to-get-free-minecoins-in-minecraft_GM479516143.pdfIn PDF document text
    • https://mbbs.hr/files/coin-master-daily-free-spins-link-2021_GM406889139.pdfIn PDF document text
    • http://mbbs.hr/files/coin-master-hack-for-ios_GM406889139.pdfIn PDF document text
    • https://mbbs.hr/files/pokemon-go-free-007_GM1094591345.pdfIn PDF document text
    • https://mbbs.hr/files/minecraft-win-10-free_GM479516143.pdfIn PDF document text
    • https://mbbs.hr/files/how-to-hack-roblox-to-get-robux_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_off00004fc9.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4FC9 24960 bytes
SHA-256: 258b8b235f3a76989404e22d0bd91790bec7bc06f24a414305b97b004ecd86f9
font_01_sfnt_off000087ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x87FF 18348 bytes
SHA-256: 9560f0e6f9a4e6be006083e3696e79311a38bb173f302534750988b281bae61f

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