Malicious PDF — malware analysis report

Static analysis result for SHA-256 b11b6756ca850729…

MALICIOUS

PDF

48.1 KB Created: 2021-06-03 13:49:48 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-16
MD5: e21423712b301ee3652bf843f11bb77b SHA-1: 48eed5e1ab588b394afa50fb7eb3d61bd24f5dd0 SHA-256: b11b6756ca850729b379a57662b9fc3628c54a8a01f1724385ea1647c7e0e5e2
260 Risk Score

Malware Insights

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

The PDF contains multiple heuristics indicating malicious redirector links and a fake CAPTCHA lure, aiming to trick users into clicking through to malicious infrastructure. The document body, though heavily obfuscated, contains references to 'Microsoft Free Robux' and a URL that aligns with the heuristic findings. The presence of embedded URLs and the overall structure suggest an attempt to deliver a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9796

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.
  • 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
  • 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/microsoft-free-robux-game-hack In PDF document text
    • https://library.sttbandung.ac.id/repository/huskybuckscom-free-robux_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-much-robux-can-you-get-with-1-million-dollars_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/coin-master-free-spins-iphone_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-coin-master-spins-blog_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-hack-minecraft-pe_GM479516143.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-pubg-uc-carding_GM1330123889.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-robux-promo-codes_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/claim-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-minecraft-codes-2021_GM479516143.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-robux-wheel_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/get-free-robux-without-human-verification_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/coin-master-free-spin-today_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/minecraft-com-free_GM479516143.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-get-free-robux-on-roblox-2021_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-get-free-robux-fast-and-easy_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/coin-master-hack-mod-game-download_GM406889139.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-robux-gift-card-codes_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/free-robux-games-that-actually-work-2021_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-get-free-robux-on-ipad-no-verification_GM431946152.pdfIn PDF document text
    • https://library.sttbandung.ac.id/repository/how-to-get-spins-for-free-on-coin-master_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
font_00_sfnt_off000050ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x50EC 27044 bytes
SHA-256: 894e8a6625eb8bee13cc3bb214e6e16bf260a9b6113bf51af91a0de578de1fd7
font_01_sfnt_off00008e82.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8E82 2984 bytes
SHA-256: a48876ea4c8ebf6e5aafed7b7988c43bbdc4f269aae7d16f65c21390373c25ca
font_02_sfnt_off000098cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x98CF 18436 bytes
SHA-256: fc8058b2753a804d67589ad9e7736472a77fa92b8b7356ad3bc1ab00ed4087a5

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