Malicious PDF — malware analysis report

Static analysis result for SHA-256 b23d1819e6df4de9…

MALICIOUS

PDF

43.2 KB Created: 2021-06-13 23:56:21 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-16
MD5: 07f621375745e7d7f7491a5444eb1e64 SHA-1: 79f49f5c146225336e60b20ff925914e00caf877 SHA-256: b23d1819e6df4de981f09fd6d08303b7970408ca672ee434998244a710ab676b
142 Risk Score

Malware Insights

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

The PDF document contains a fake CAPTCHA and download button lure, directing users to download potentially malicious files from external URLs. The document body and embedded URLs suggest a lure for game hacks or exploits, such as 'robux' or 'coin master' cheats. The presence of numerous external links and the ML classifier's high confidence score indicate a malicious intent to trick users into downloading further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

Heuristics 5

  • 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.
  • 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 http://netcdn.co/app/431946152/download-robux-online-hack-game-hack PDF link annotation
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/coin-master-free-spins-and-coins-today-gift-reward_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/how-to-hack-someones-roblox-account-2021_GM431946152.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/pokemon-go-free-account-username-and-password_GM1094591345.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/coin-master-hack-ios-download-2021_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/coin-master-free-spin-realme-products_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/free-robux-real_GM431946152.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/how-can-i-get-free-spins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/coin-master-fan-page-free-spins_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/minecraft-free-app_GM479516143.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/how-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/coin-master-hack-apk-latest-version-2021_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/free-minecraft-wallpaper_GM479516143.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/free-account-roblox-2021_GM431946152.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/roblox-free-robux_GM431946152.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/coin-master-free-spins-link-without-human-verification_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/daily-coin-master_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/free-roblox-accounts_GM431946152.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/instagram-free-coin-master-spins_GM406889139.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/free-robux-codes-2021-not-used_GM431946152.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/minecraft-dungeons-free-download_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_003_off00004b75.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4B75 24812 bytes
SHA-256: 61b85e877ca71d45cbc65849ba610290c9800576cc8a1250a45f3d3c72680749
font_01_sfnt_off00008482.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8482 18948 bytes
SHA-256: 3d172a85f1e460f59d7c0e67e4b8bf1f37db769e020cc35b2074d076db589f68

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