Malicious PDF — malware analysis report

Static analysis result for SHA-256 909cf990ac3ece51…

MALICIOUS

PDF

45.5 KB Created: 2021-06-11 05:46:45 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-24
MD5: ab7b45b3f228fde7a7f4e8eb834039bd SHA-1: f243f0c048b8eff55e600cbbb57d958f08ea9495 SHA-256: 909cf990ac3ece51750b1ec8a4f814fb9571eaa7e9246fd18b574a2de46c2b77
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/how-to-kick-anyone-from-roblox-server-hack-script-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/how-to-kick-anyone-from-roblox-server-hack-script-game-hack PDF link annotation
    • http://katalog.gemalibrary.net/repository/coin-master-free-spins-blogspot_GM406889139.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/how-to-make-free-robux_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/minecraft-windows-10-free-with-java_GM479516143.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/websites-that-give-you-free-robux_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/coin-master-spins-and-coins_GM406889139.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/code-cheat-roblox-to-tchat_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/what-is-a-robux_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/getbucks-roblox-free_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/como-hackear-roblox-para-tener-robux-infinitos-para-pc_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/robux-sites_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/free-robux-exe_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/coin-master-free-spin-today_GM406889139.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/haktuts-coin-master-free-daily-spins_GM406889139.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/how-to-hack-roblox-on-mobile_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/roblox-free-wings_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/free-robux-only-1-step_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/how-to-earn-free-robux_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/how-do-u-hack-roblox_GM431946152.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/minecraft-realms-free-trial_GM479516143.pdfIn PDF document text
    • http://katalog.gemalibrary.net/repository/coin-master-free-spins-cheat_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
font_00_sfnt_off0000534c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x534C 24712 bytes
SHA-256: 4fed845630fdc4f89030e869241926603c28d437e80ba523bbdc07cc729bb4c0
font_01_sfnt_off00008bea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8BEA 19464 bytes
SHA-256: f223d085471675aabd646bed07a9c34d433460cba88aa2637886ec48f24a7adc

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