Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b1a426d20ee4f6…

MALICIOUS

PDF

48.0 KB Created: 2021-05-12 04:02:07 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 2ba4906ce0fe167163d7bf64ffcb7bdc SHA-1: 52a56eff7721f50249a4e31daccbb545bb0f2ee7 SHA-256: 81b1a426d20ee4f6a5b82a213d49c59479e086e73214438e6c4dd8710741e849
228 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and multiple links to redirectors and external PDF files, many of which are related to game cheats and free in-game currency. This suggests a lure to drive traffic to malicious sites or potentially download further payloads. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9013

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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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/406889139/free-daily-spins-coin-master-2021-game-hack In PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/free-spins-coin-master-october-17-2021_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/how-to-get-free-robux-fast_GM431946152.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coin-master-free-spins-link-blogspot-today_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/free-robux-generator-no-verification-2021_GM431946152.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/roblox-ftw_GM431946152.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/hack-coin-master-link_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/minecraft-font-free_GM479516143.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coin-master-free-spins-whatsapp-link_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/moonactive-coin-master-free-spins-link_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/haktuts-coin-master-free-spin-link_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/free-promo-codes-for-robux_GM431946152.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/minecraft-free-download-no-virus_GM479516143.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coin-master-free-spins-link-iphone_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coin-master-hack-lost-world-2021-com_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coinmaster-spin-ml-free_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coin-master-hack-com_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coin-master-daily-free-spins-link-facebook_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/coin-master-daily-free-spin-app_GM406889139.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/free-robux-games-that-actually-work-2021_GM431946152.pdfIn PDF document text
    • http://www.ishvani.com/www/js/ckfinder/userfiles/files/roblox-hair-for-free_GM431946152.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_003_off00004bd3.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4BD3 25092 bytes
SHA-256: 375970219a500040ca9701b56ecabdc76ccc57e474990285399ad61189f185c4
font_01_sfnt_off000085c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x85C0 7332 bytes
SHA-256: d811e0aca85f3b94c42cd1240eec68b8eb378f3d8be5e408d3f6abd0f11f834d
font_02_sfnt_off000097d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x97D9 18708 bytes
SHA-256: c65851a3c2ccf8ba249fbb480ab00bab2dc65c52c70fe6f18183c59a9b34b022