Malicious PDF — malware analysis report

Static analysis result for SHA-256 28ffe2e8f9bf13d6…

MALICIOUS

PDF

50.0 KB Created: 2021-06-07 09:45:29 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7)
MD5: 6c8ba40cf1055d7850d2951a48b30a08 SHA-1: 0e3a52c2e30063e3c081aabaa3ac5f5ba36e0df6 SHA-256: 28ffe2e8f9bf13d6d83e0e89db0d92e1721ea8f89021cc1e1043e81ddb9e80d5
162 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF document contains numerous links to external websites, many of which are structured as SEO-optimized PDF links, suggesting a link farm or content aggregation strategy. The presence of a security bypass instruction and the ML classifier's high confidence score indicate malicious intent. The document likely aims to trick users into downloading further malicious content or visiting phishing sites by leveraging lures related to popular games.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9796

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.
  • Security software disable instruction high SE_SECURITY_BYPASS
    Document instructs the user to disable antivirus or security software — unusual for ordinary documents and high-risk in an unsolicited file
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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/hack-roblox-pc-robux-game-hack
    • http://deyuan-pc.com.tw/images/coin-master-free-spins-coins_GM406889139.pdf
    • http://deyuan-pc.com.tw/images/coin-master-hack-without-verification-code_GM406889139.pdf
    • http://deyuan-pc.com.tw/images/coin-master-hack-download-2021_GM406889139.pdf
    • http://deyuan-pc.com.tw/images/free-texture-packs-for-minecraft-pe_GM479516143.pdf
    • http://deyuan-pc.com.tw/images/how-to-download-minecraft-windows-10-edition-for-free_GM479516143.pdf
    • http://deyuan-pc.com.tw/images/how-to-make-roblox-clothes-for-free_GM431946152.pdf
    • http://deyuan-pc.com.tw/images/can-you-actually-get-free-robux_GM431946152.pdf
    • http://deyuan-pc.com.tw/images/free-robux-accounts_GM431946152.pdf
    • http://deyuan-pc.com.tw/images/coin-master-hacks-for-spins_GM406889139.pdf
    • http://deyuan-pc.com.tw/images/minecraft-for-free-on-phone_GM479516143.pdf
    • http://deyuan-pc.com.tw/images/minecraft-beta-free_GM479516143.pdf
    • http://deyuan-pc.com.tw/images/what-games-on-roblox-give-you-free-robux_GM431946152.pdf
    • http://deyuan-pc.com.tw/images/pokemon-go-free-7km-egg-list_GM1094591345.pdf
    • http://deyuan-pc.com.tw/images/coin-master-heaven-daily-free-spins-link-today_GM406889139.pdf
    • http://deyuan-pc.com.tw/images/free-robux-rewards_GM431946152.pdf
    • http://deyuan-pc.com.tw/images/free-spins-and-coins-coin-master-link-2021_GM406889139.pdf
    • http://deyuan-pc.com.tw/images/minecraft-on-computer-free_GM479516143.pdf
    • http://deyuan-pc.com.tw/images/blox-land-free-robux_GM431946152.pdf
    • http://deyuan-pc.com.tw/images/how-to-get-minecraft-on-chromebook-for-free_GM479516143.pdf
    • http://deyuan-pc.com.tw/images/free-coin-master-coins_GM406889139.pdf
    • http://en.wikipedia.org/wiki/MIT_License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off00005243.bin
2eb77c703f757d6b9bdc51d01c0f7f73092795dd822b706a20ec96f3273ab96a
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5243 28164 bytes
font_01_sfnt_off0000936b.bin
9a13c2580265a78e8a7257496a31ee0055738af7e20a5661c2902efe4bf05ce5
pdf-font-stream PDF embedded font (sfnt) at offset 0x936B 5596 bytes
font_02_sfnt_off0000a012.bin
ae80be787ee2aa1c29cbf291d35afb7d500609dc4404daa90daacd13c0e52a5f
pdf-font-stream PDF embedded font (sfnt) at offset 0xA012 18476 bytes