Malicious PDF — malware analysis report

Static analysis result for SHA-256 c90b089a3477f67a…

MALICIOUS

PDF

42.3 KB Created: 2021-05-15 08:04:12 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-25
MD5: 41debe1a7e796731b5a8441c82079bb0 SHA-1: 23b957fc0e21869bc47e0d493f95541c553da176 SHA-256: c90b089a3477f67aa4005038d3f8d14a2ebf7f3668dddd71c725391a4bba0fd8
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 a fake-CAPTCHA lure. 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 0.9971

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.
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • 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.xyz/app/431946152/rbx-place-free-robux-game-hack PDF link annotation
    • http://keepcasscountybeautiful.com/images/how-to-get-hacks-on-roblox_GM431946152.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/coin-master-free-coins-2021_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/coin-master-free-spins-hack_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/how-to-get-minecraft-coins-for-free_GM479516143.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/free-robux-hack-no-verification_GM431946152.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/coin-master-hack-android-2021_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/free-coin-master-androd-cheats-2021_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/coin-master-links-free-spins_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/minecraft-clipart-free_GM479516143.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/websites-that-give-free-robux_GM431946152.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/free-robux-no-human-verify_GM431946152.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/free-coin-master-spins-daily_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/how-to-get-free-hats-on-roblox_GM431946152.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/play-minecraft-free-online-no-download_GM479516143.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/how-to-get-free-spins-and-coins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/roblox-robux-hack_GM431946152.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/coin-master-hack-spin_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/hack-coin-master-free_GM406889139.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/free-robux-by-watching-ads_GM431946152.pdfIn PDF document text
    • http://keepcasscountybeautiful.com/images/coin-master-cheats-and-hacks_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
stream_003_off000045d5.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x45D5 26688 bytes
SHA-256: 7f93631ed78a1b761db14f95af47e1c6a306f9795b6d1e4a462d048ea9eefe47
font_01_sfnt_off0000829f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x829F 18472 bytes
SHA-256: 30b20ae3df441f067d6970d2fc85ed95190924e4fa28fb295b294374bf1be820

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