Malicious PDF — malware analysis report

Static analysis result for SHA-256 91cd8fb00511f24d…

MALICIOUS

PDF

37.0 KB Created: 2021-07-04 01:48:19 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 5471e3299bdcf8d428d4abcff65cec6e SHA-1: 252bd90254c1e13d8fabb7e2ea23ee0b86a2d4c8 SHA-256: 91cd8fb00511f24d278351a8926a6dcb9dfdf1bec9fb99c121c9c88d266a022f
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, including a known malicious redirector, disguised as "free generator / game hack" lures. The document body and heuristics indicate a pattern of linking to numerous PDF files, likely part of a link farm or SEO manipulation to drive traffic to potentially malicious content. The presence of embedded URLs and the ML classifier's high confidence score support this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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.
  • 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.
  • 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 http://netcdn.tw/app/479516143/minecraft-apk-free-download-016-0-game-hack In PDF document text
    • http://lib.baruna-husada.ac.id//repository/coin-master-free-spins-1-coin-master_GM406889139.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/spin-and-coin_GM406889139.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/how-to-get-free-robux-in-2-seconds_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/how-to-get-free-robux-on-chromebook_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/how-to-get-free-robux-without-download-apps-or-survey_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/free-account-roblox-with-robux_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/how-to-get-free-robux-and-tix-for-real_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/coin-master-free-spin-link-today-16-11-2021_GM406889139.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/2021-free-coin-master-spins_GM406889139.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/grabpoints-robux_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/minecraft-pe-free-download-ios_GM479516143.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/how-to-hack-point-for-robux-site-for-unlimited-points_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/coin-master-hack-tool-access-online-generator_GM406889139.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/free-coins-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/free-robux-no-verification-no-survey_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/coin-master-gold-cards-hack_GM406889139.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/minecraft-free-download-mac_GM479516143.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/easy-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id//repository/minecraft-pe_GM479516143.pdfIn PDF document text
    • http://lib.baruna-husada.ac.id/repository/coin-master-links-for-today_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
font_00_sfnt_off00003866.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x3866 22636 bytes
SHA-256: c59de2b7ba3abc1dad6d2cf564377a616cc15984905f1d1b87e5b452f86689ca
font_01_sfnt_off00006ace.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6ACE 19372 bytes
SHA-256: 199fc5fb5555a01dd07f1f7af865c4c0146787c368d5cdea82e8d68cb589e1c5

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