Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8b786bc11df507f…

MALICIOUS

PDF

46.1 KB Created: 2021-06-11 07:07:27 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: 2d3d2ea44897b71d039219e0958f639b SHA-1: 644a23906f66a4b35cc4163c190f088c5e7760e7 SHA-256: a8b786bc11df507f7676b904574bb959bf7cb4fadade41b106217521846d0781
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/marshmello-shirt-roblox-free-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/marshmello-shirt-roblox-free-game-hack PDF link annotation
    • https://digilib.stimlog.ac.id/repository/roblox-adopt-me-money-cheat_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/hack-slash-roblox-id_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/how-to-get-coin-master-free-spin-link_GM406889139.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/free-domain-for-minecraft-server_GM479516143.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/how-to-get-a-free-dominus-hat-on-roblox-2021_GM431946152.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/roblox-free-play-online-login_GM431946152.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/martian-lettuce-coin-master-free_GM406889139.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/como-tener-robux-gratis-con-hacks_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/free-to-take-roblox-eye-for-makeup_GM431946152.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/how-to-get-20210-robux-for-free_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/how-to-get-free-roblox-items_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/da-hood-hack-tuto-roblox_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/minecraft-hacker-skin_GM479516143.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/free-daily-coin-master-coins_GM406889139.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/free-spins-coin-master-links-blogspot_GM406889139.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/minecraft-free-download-mobile_GM479516143.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/free-spin-link_GM406889139.pdfIn PDF document text
    • http://digilib.stimlog.ac.id/repository/how-to-get-free-roblox-money_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/robux-for-free-on-ipad_GM431946152.pdfIn PDF document text
    • https://digilib.stimlog.ac.id/repository/free-minecraft-codes-2021_GM479516143.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_off00005172.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5172 26752 bytes
SHA-256: 80c4d58ad456bea67d88cbbc4bb62dac52e96677d2bfd89fa81048fbe6eaf47d
font_01_sfnt_off00008fd6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8FD6 19020 bytes
SHA-256: e66961e5f8d580d1b9d2c75dc3e6c78070c1a7880b5206e7a04bc58211adc3e5

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