Malicious PDF — malware analysis report

Static analysis result for SHA-256 78de61b3ff280c8e…

MALICIOUS

PDF

35.7 KB Created: 2021-07-04 04:43:15 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-18
MD5: c1c7444374af90a8c26503da2574d7fb SHA-1: 5b8893023a77fb372c6a3c7d115a12377049b2aa SHA-256: 78de61b3ff280c8ec325d36caa178618c6688db707a74e5ce0997bb112ffe877
142 Risk Score

Malware Insights

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

This PDF document contains numerous links to external websites, many of which are presented as 'game hacks' or 'free items'. The heuristic 'PDF_SEO_LINK_FARM' indicates a large number of such links, suggesting a link farm or SEO poisoning tactic. The primary URL http://netcdn.tw/app/406889139/free-spins-coin-master-march-2021-game-hack is likely a redirector to malicious content or a downloader for a second-stage payload. No scripts were extracted, but the PDF structure and embedded links strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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.tw/app/406889139/free-spins-coin-master-march-2021-game-hack PDF link annotation
    • https://edu.kyst.com.tw/image/data/files/free-roblox-admin-codes_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/coin-master-email-rewards_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-spin-hack-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-to-earn-free-robux_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/pokemon-go-free-zekrom_GM1094591345.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/dragon-ball-super-2-roblox-hack_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-minecraft-education-edition_GM479516143.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-roblox-from-gor-rs_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/descargar-hack-coin-master_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/coin-master-free-spins-link-2021_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-robux-generator-no-human-verification-or-offers_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-robux-no-human-verification_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/minecraft-pe-apk-free-download_GM479516143.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/earn-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/i-got-hacked-on-roblox_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/robux-hacks-2021_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/coin-master-free-spin-daily-link_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-spin-coin-master-instagram_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/is-auto-clicker-cheating-in-roblox_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-to-get-free-rep-on-roblox-got-talent_GM431946152.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_002_off00003383.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x3383 23056 bytes
SHA-256: bdba06adcf7b94f0fbc37b91456ab2bdaa6da497f26fe4bf2387826ca180b1fc
font_01_sfnt_off00006778.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6778 18744 bytes
SHA-256: f992392ed04d58b53e0de1c6bbd6ac77b4f3b3aa4afbe9104984b67ade831bee

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