Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b91e8fc05fae038…

MALICIOUS

PDF

42.9 KB Created: 2021-05-15 03:34:20 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 6bd5cbc32d93be4bf24c553ddfcacd5a SHA-1: 30458c9467417832bc5900a2f432f99fbf71554f SHA-256: 5b91e8fc05fae0389c5d43245befa33f9b8168ce7df1b6b808c91ed4dd240e85
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a critical heuristic firing for a game hack redirect lure, pointing to a known malicious URL. The document body, though heavily obfuscated, contains references to 'free Robux' and a URL that aligns with the heuristic findings. The presence of embedded URLs and the ML classifier's high confidence score further support the malicious nature of this document, likely intended to redirect users to a phishing or malware distribution site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 4

  • 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.
  • 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.xyz/app/431946152/how-can-i-get-free-robux-game-hack In PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/roblox-free-robux-com_GM431946152.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/coin-master-hack-ios-no-jailbreak_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-coin-master-spins_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-robux-generator-no-human-verification-or-survey-2021_GM431946152.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/how-to-play-coin-master_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/coin-master-pc-hack-download_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/www-coin-master-hack-tk_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/get-free-spins-in-coin-master_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-spin-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-robux-hack-generator_GM431946152.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/but-link-says-free-robux_GM431946152.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/coin-master-hack-no-human-verification-2021_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/coin-master-hack-with-lucky-patcher_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/how-to-get-free-robux-generator_GM431946152.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-spin-appscoin-master_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-robux-without-offers_GM431946152.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-coins-and-spins-2021_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/free-robux-gen_GM431946152.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/hack-coin-master-download_GM406889139.pdfIn PDF document text
    • https://www.marshlands.staffs.sch.uk/admin/ckfinder/userfiles/files/coin-master-unlimited-free-spins_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
stream_003_off0000490c.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x490C 25660 bytes
SHA-256: fc9946f1c044f33dfac5d70c1e2ac7da9f87421068154730017f8d15403c66df
font_01_sfnt_off0000848b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x848B 18512 bytes
SHA-256: 69cba7171cc96811b03769255314e8880e2b1f1f28661a6eda79c3c7ec8a929e

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