Malicious PDF — malware analysis report

Static analysis result for SHA-256 39c6fe2237b1fe23…

MALICIOUS

PDF

45.1 KB Created: 2021-06-11 07:25:26 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7)
MD5: c5f238af4d2f6975d6ce2a65ddf1d66a SHA-1: c8bd283aa22cb6c85f32774f9c2a8bee5ed9ba9e SHA-256: 39c6fe2237b1fe23f73c0305461e9180ce0209601726a7b26904df75dbeb47e1
102 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs and a link farm heuristic firing, indicating it is designed to direct users to external websites. The document body, though heavily corrupted, contains references to 'Roblox Free Robux' and similar game-related lures, suggesting a phishing or scam attempt. The ML classifier also flagged this PDF as malicious with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

Heuristics 4

  • 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.
  • 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/roblox-free-robux-no-phone-number-game-hack
    • https://vireco-online.com/ckfinder/userfiles/files/free-roblox-promo-codes-september-2021_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/how-to-hack-coin-master-facebook_GM406889139.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-roblox-animations_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/give-me-robux-now_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/roblox-how-to-get-free-clothes_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-robux-codes-generator_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/coin-master-free-spin-app-reviews_GM406889139.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/without-tiktok-free-view-iphone-11_GM835599320.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-roblox-accounts-that-work_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-links-for-free-coins-and-spins-for-coin-master_GM406889139.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/coin-master-free-spins-no-human-verification_GM406889139.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-minecraft-realm-codes_GM479516143.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-roblox-accounts-with-robux-that-work-2021_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/fb-coin-master-free-spins-link_GM406889139.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/how-to-make-a-free-minecraft-account_GM479516143.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-roblox-svg_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/free-robux-codes-not-used_GM431946152.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/minecraft-servers-that-allow-hacks_GM479516143.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/coin-master-free-coins-and-spins-link-2021_GM406889139.pdf
    • https://vireco-online.com/ckfinder/userfiles/files/coin-master-free-spin-daily-link_GM406889139.pdf
    • http://en.wikipedia.org/wiki/MIT_License

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off0000554e.bin
fb57fabbbe108afc7efc070322f2a925903a250ccea41fd39c6b4dffd67d3c04
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x554E 25056 bytes
font_01_sfnt_off00008d02.bin
5fa10bfce7521d511f39218706d966ce71a7fa35a59c44baede4b5829884d0fb
pdf-font-stream PDF embedded font (sfnt) at offset 0x8D02 18668 bytes