Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3c9238dca79cc42…

MALICIOUS

PDF

45.3 KB Created: 2021-06-07 15:02:05 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7)
MD5: 44b95acd88a5c25b3b990464242608a2 SHA-1: 544b4bd3bc1c067af21e9e0a58335fbf3bc397a2 SHA-256: a3c9238dca79cc42e08ef7d1e76d82e32f99dd441bf640f966364a754f385a29
102 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are structured as SEO-optimized PDF gateways. The primary URL, 'https://netcdn.tw/app/431946152/how-to-buy-robux-for-free-2021-game-hack', suggests a lure for obtaining free in-game currency or items. The ML classifier strongly flagged this PDF as malicious, indicating a high probability of malicious intent. No scripts were extracted, but the extensive linking and the ML detection point towards a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9864

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/how-to-buy-robux-for-free-2021-game-hack
    • http://grupodin.com.br/images/get-free-followers-on-tiktok_GM835599320.pdf
    • http://grupodin.com.br/images/minecraft-hacks-for-2b2t_GM479516143.pdf
    • http://grupodin.com.br/images/how-to-get-unlimited-robux_GM431946152.pdf
    • http://grupodin.com.br/images/coin-master-gift-hack_GM406889139.pdf
    • http://grupodin.com.br/images/free-robux-2021_GM431946152.pdf
    • http://grupodin.com.br/images/cute-free-hair-on-roblox_GM431946152.pdf
    • http://grupodin.com.br/images/what-is-coin-master-app_GM406889139.pdf
    • http://grupodin.com.br/images/links-for-free-spins-for-coin-master_GM406889139.pdf
    • http://grupodin.com.br/images/free-spins-and-coins-blogspot-coin-master_GM406889139.pdf
    • http://grupodin.com.br/images/roblox-skins-boy-free_GM431946152.pdf
    • http://grupodin.com.br/images/coin-master-hack-apk-facebook-login_GM406889139.pdf
    • http://grupodin.com.br/images/free-robux-no-verify_GM431946152.pdf
    • http://grupodin.com.br/images/roblox-free-play_GM431946152.pdf
    • http://grupodin.com.br/images/hack-para-coin-master-singapore_GM406889139.pdf
    • http://grupodin.com.br/images/minecraft-bedrock-free-with-java_GM479516143.pdf
    • http://grupodin.com.br/images/how-to-get-2021-robux-for-free_GM431946152.pdf
    • http://grupodin.com.br/images/coin-master-apk-free-download_GM406889139.pdf
    • http://grupodin.com.br/images/get-free-spins-on-coin-master_GM406889139.pdf
    • http://grupodin.com.br/images/10-free-spins-coin-master_GM406889139.pdf
    • http://grupodin.com.br/images/free-tiktok-followers-without-human-verification-2021_GM835599320.pdf
    • http://en.wikipedia.org/wiki/MIT_License

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off0000503b.bin
064b545585a03752a2683aa21ee7cd8b921ec241ced3e59e46d1d5e5c6431d29
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x503B 27412 bytes
font_01_sfnt_off00008cfe.bin
632d723f22b0036b46c9174c949a49c01edcfe69b4b633ad7358dec715807d73
pdf-font-stream PDF embedded font (sfnt) at offset 0x8CFE 18760 bytes