Malicious PDF — malware analysis report

Static analysis result for SHA-256 639ba94b73a5779e…

MALICIOUS

PDF

41.4 KB Created: 2021-05-17 06:48:16 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-04
MD5: ed5c17ac16352a0e51c21f2afb542380 SHA-1: 1c17fdfcef414777b7aabda14a63da2ebd583191 SHA-256: 639ba94b73a5779e3329a8339509221a6fcaf438adbf5f0bae33c19d7a4021d8
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/406889139/500-free-spins-coin-master-game-hack PDF link annotation
    • https://www.gymun.cz/images/how-you-get-free-robux_GM431946152.pdfIn PDF document text
    • https://www.gymun.cz/images/pasos-para-hackear-coins-master_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/minecraft-windows-10-hack-client-2021_GM479516143.pdfIn PDF document text
    • https://www.gymun.cz/images/coin-master-hack-download-apk_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/hack-coin-master-online-without-human-verification_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/coin-master-pro-hack_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/coin-master-free-spins-hacktman_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/free-spins-coin-master-unlimited_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/free-robux-no-verification-at-all_GM431946152.pdfIn PDF document text
    • https://www.gymun.cz/images/coin-master-free-coins-and-spins-2021_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/free-roblox-generator-for-roblox_GM431946152.pdfIn PDF document text
    • https://www.gymun.cz/images/chisel-and-bits-mod-minecraft-pe_GM479516143.pdfIn PDF document text
    • https://www.gymun.cz/images/roblox-free-clothes-hack_GM431946152.pdfIn PDF document text
    • https://www.gymun.cz/images/bloxpink-free-robux_GM431946152.pdfIn PDF document text
    • https://www.gymun.cz/images/coin-master-free-spins-link-download-ios_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/get-gold-coin-master-village-hack_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/how-to-get-more-robux-for-free_GM431946152.pdfIn PDF document text
    • https://www.gymun.cz/images/coin-master-free-spin-and-coin_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/how-to-win-attack-madness-in-coin-master-hack_GM406889139.pdfIn PDF document text
    • https://www.gymun.cz/images/roblox-hacks-and-cheats_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_003_off0000480d.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x480D 25180 bytes
SHA-256: 8c3699ed77e0d9ee871ebb1fb2fe5adbcc066a32af3fa1737376371199f42065
font_01_sfnt_off00007fa7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7FA7 18192 bytes
SHA-256: a4943b7840cd3959a8ceaa1ed690fa7e50048a9b71dafef76241fe8ac415bb35

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