Malicious PDF — malware analysis report

Static analysis result for SHA-256 36628448d6d815d4…

MALICIOUS

PDF

49.8 KB Created: 2021-06-13 15:10:51 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-01
MD5: df98b4c1af7bf58551185b44b450194d SHA-1: c64520be60608efc39f877ae9111a9db99a11bd6 SHA-256: 36628448d6d815d49fea95cef7c7f16a700e29e7d85e499a7d6dac5f92bc9e3c
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF document was flagged as malicious by an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, routes users through malicious redirector infrastructure and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9796

Heuristics 5

  • 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.
  • PDF links to a 'free generator / game hack' redirector high 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.
  • 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
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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.co/app/431946152/free-robux-no-human-verification-or-download-or-survey-game-hack PDF link annotation
    • http://kumotor.com.tw/upload/userfiles/files/how-to-get-free-coins-in-mcpe-master_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/how-to-get-free-roblox-gift-cards_GM431946152.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/how-to-hack-robux_GM431946152.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/roblox-login-hack-password_GM431946152.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/coin-master-hack-ios-download-2021_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/coin-master-free-daily-spins_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/coin-master-latest-version-hack_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/free-spins-for-coin-master-game_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/play-minecraft-online-free_GM479516143.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/open-coin-master_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/coin-master-free-spins-link-no-verification-2021_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/how-to-get-free-spins-in-coin-master_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/coin-master-free-link-today_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/pokemon-go-kanto-tour-free-version_GM1094591345.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/how-to-get-free-robux-in-2021_GM431946152.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/coin-master-hack-september-2021_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/free-vip-server-roblox_GM431946152.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/how-to-get-free-coins-on-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/roblox-troll-outfits-free_GM431946152.pdfIn PDF document text
    • http://kumotor.com.tw/upload/userfiles/files/free-coin-master-coins_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_off000050fb.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x50FB 26936 bytes
SHA-256: afaae13dbd9ec9299c4aa8ab675b0174904753ed7915179d24b11f7313be0eba
font_01_sfnt_off00008ece.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8ECE 3884 bytes
SHA-256: 40b61f8938bd710dc29dc58ba3fde91c245a6a69596ec569b4d27c769ca417cf
font_02_sfnt_off00009b76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9B76 19736 bytes
SHA-256: 920059caa77cb159c11543bc590559935675b843b2b09dff931d9880bb34a694

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