Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a26e4ad5634afd8…

MALICIOUS

PDF

55.5 KB Created: 2021-06-09 02:52:24 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7)
MD5: a2c9f01ef6c0c768e6d2415e20ce59d0 SHA-1: c9128c4d2ac54ee446d2b66d41878734c6a2d319 SHA-256: 8a26e4ad5634afd8a7d4d0e76fb37a022c3af1fcfdfdcbaee68e5c05cdc92219
82 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The document presents a fake CAPTCHA to trick users into clicking a malicious link, likely to download a second-stage payload or phish for credentials. The embedded URL `https://netcdn.tw/app/431946152/claimrbx-free-robux-game-hack` is a primary indicator of this malicious intent. While no scripts were explicitly extracted, the PDF structure and heuristics suggest an attempt to exploit user interaction.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9649

Heuristics 4

  • 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.tw/app/431946152/claimrbx-free-robux-game-hack
    • https://vosco.vn/uploads/vosco.vn/files/coin-master-hack-xyz-download-free_GM406889139.pdf
    • https://vosco.vn/uploads/vosco.vn/files/minecraft-pocket-edition-free-apk_GM479516143.pdf
    • https://vosco.vn/uploads/vosco.vn/files/free-robux-without-downloading-apps_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/coin-master-hack-app-ios_GM406889139.pdf
    • https://vosco.vn/uploads/vosco.vn/files/minecraft-free-minecoins_GM479516143.pdf
    • https://vosco.vn/uploads/vosco.vn/files/how-to-free-robux_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/coin-master-free-daily-spins-link_GM406889139.pdf
    • https://vosco.vn/uploads/vosco.vn/files/free-robux-scams_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/where-to-get-free-robux_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/robux-sign_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/get-free-robux-generator_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/roblox-promo-codes-free-robux_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/weight-lifting-simulator-2-roblox-hack_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/free-online-spins-coin-master_GM406889139.pdf
    • https://vosco.vn/uploads/vosco.vn/files/free-minecraft-java-account_GM479516143.pdf
    • https://vosco.vn/uploads/vosco.vn/files/free-robux-generator-without-human-verification_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/roblox-catalog-free_GM431946152.pdf
    • https://vosco.vn/uploads/vosco.vn/files/best-free-minecraft-skins_GM479516143.pdf
    • https://vosco.vn/uploads/vosco.vn/files/spin-link-coin-master_GM406889139.pdf
    • https://vosco.vn/uploads/vosco.vn/files/free-followers-on-tiktok-no-human-verification_GM835599320.pdf
    • http://en.wikipedia.org/wiki/MIT_License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off000053fe.bin
b6f5a3b0300ad5089f283acc1ca030b59c3171e4d752687cd27502eeec358060
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x53FE 38956 bytes
font_01_sfnt_off0000a892.bin
1ba32a5139c6de22584ee0f72d573162a644f7c4206fa3a2a8dea775e8e2a087
pdf-font-stream PDF embedded font (sfnt) at offset 0xA892 3988 bytes
font_02_sfnt_off0000b5af.bin
cfa2fb642045145230a20b139508f2677ace4dfe3e3be0c8823c50af7163445a
pdf-font-stream PDF embedded font (sfnt) at offset 0xB5AF 18696 bytes