Malicious PDF — malware analysis report

Static analysis result for SHA-256 820cd8f364c03eb2…

MALICIOUS

PDF

51.5 KB Created: 2021-06-03 07:07:13 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 537ddd0c80e89c516c2d270e655ab52f SHA-1: 2bd188ee6a2438a4b1e1119724ce5fb7071673b4 SHA-256: 820cd8f364c03eb23678fe4f10a422b042aea693ae2c34afd6e09c0a029688cf
200 Risk Score

Malware Insights

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

The PDF document employs a fake CAPTCHA and a download lure to trick users into clicking a link. This link, https://netcdn.online/app/431946152/oprewards-free-robux-game-hack, leads to a known malicious redirector, likely intended to deliver a second-stage payload or phish for credentials. The ML classifier also flagged this PDF with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9327

Heuristics 5

  • 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
  • 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/oprewards-free-robux-game-hack In PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/how-to-get-free-robux-2021_GM431946152.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/minecraft-rtx-download-free_GM479516143.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/roblox-hack-me-robux_GM431946152.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/how-to-get-free-robux-on-phone_GM431946152.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/roblox-free-robux-codes_GM431946152.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/free-spin-link-coin-master-app_GM406889139.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/roblox-fun-com-free-robux_GM431946152.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/coin-master-hack-club_GM406889139.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/tiktok-download-free-jio-phone_GM835599320.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/free-bedrock-minecraft_GM479516143.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/minecraft-free-play-no-download_GM479516143.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/free-roblox-printables_GM431946152.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/free-minecraft-worlds_GM479516143.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/rbx-land-free-robux_GM431946152.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/minecraft-mod-menu-apk_GM479516143.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/coin-master-games-hack_GM406889139.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/how-to-get-free-coins-in-coin-master_GM406889139.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/pubg-uc-mtc_GM1330123889.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/coin-master-heaven-free-spins_GM406889139.pdfIn PDF document text
    • https://gzhi.govvrn.ru/uploads/ckfinder/userfiles/files/the-coin-master-hack_GM406889139.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_004_off00004f01.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4F01 25708 bytes
SHA-256: 554a682301002301b74c723a59155993a3109b7b4c3fa58f6b422f7daa437a0a
font_01_sfnt_off00008a31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8A31 8252 bytes
SHA-256: 7ebedd6b182173c8e55836cb0d114b2c4a0ac85c96a51b9f0706c935f8415fea
font_02_sfnt_off0000a546.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xA546 18756 bytes
SHA-256: ea6a04d6c65882c9dd78ee7ca96c70e45062fdc6b69d68e2fcdc099d3abb6428

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