Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5f1c6dcf9ff450e…

MALICIOUS

PDF

45.5 KB Created: 2021-06-08 15:15:17 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: a5e20d093a020fe33a4801e4bbe77efd SHA-1: 34541e5a3b3c62a1a17e0e7d1b640b7f03d2fc41 SHA-256: a5f1c6dcf9ff450ef0b557f374de3719b1df43afc04e84a589cf29b2123b79bf
182 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by an ML classifier. It uses brand-impersonation credential phishing. 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 0.9864

Heuristics 6

  • 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.
  • Brand-impersonation credential phishing lure high SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: call-to-action link host does not match the impersonated brand: https://netcdn.tw/app/431946152/free-robux-codes-on-iphone-game-hack.
  • 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 https://netcdn.tw/app/431946152/free-robux-codes-on-iphone-game-hack PDF link annotation
    • http://digilib-ppsunisma.ac.id/repository/how-to-get-free-stuff-on-roblox-2021-on-phone_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/is-roblox-free-on-pc_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/coin-master-free-spin-generator-without-human-verification_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/free-daily-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/free-robux-codes-2021_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/how-to-really-hack-coin-master_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/free-pe_GM479516143.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/hey-google-how-do-you-get-free-robux_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/roblox-lawsuit_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/how-do-you-get-free-robux-without-paying_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/google-coin-master-free-spins_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/coin-master-3rd-village-free-2021-gift-card_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/get-free-robux-info_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/free-spin-coin-master-2021-link_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/coin-master-free-spins-2021_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/free-robux-codes-no-verification_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/free-coins-coin-master-link_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/free-robux-sites-that-work_GM431946152.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/united-gaming-net-coin-master-hack_GM406889139.pdfIn PDF document text
    • http://digilib-ppsunisma.ac.id/repository/pubg-uc-770_GM1330123889.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_004_off000052ad.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x52AD 25812 bytes
SHA-256: fc0f01ae582e97edb82b7e4ca84f077b331f025604baa79f5a2cdbe90ead2da5
font_01_sfnt_off00008ec4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8EC4 18532 bytes
SHA-256: 5614a86d6d42eb0d39476798b5302e9b297c43e66b388d94e9b42be8bd11d51f

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