Malicious PDF — malware analysis report

Static analysis result for SHA-256 a13fbfb2280c5d3a…

MALICIOUS

PDF

43.9 KB Created: 2021-05-20 01:40:25 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7)
MD5: fb4ed6ecb611a0d4528d9213a0b6c68f SHA-1: 5408d4620976fb4061372dbaba49d1acb5e6c461 SHA-256: a13fbfb2280c5d3a9a3ebeb8f85a146fd9a85ada870310baae86394e15e431a1
82 Risk Score

Malware Insights

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

The document exhibits characteristics of a malicious PDF, including a high-confidence ML classifier hit and a fake CAPTCHA lure designed to trick users into interacting with the document. The presence of external URIs, such as 'https://netcdn.xyz/app/835599320/tiktok-free-anime-websites-game-hack', suggests an attempt to redirect the user to a malicious site or download a secondary payload. While no scripts were explicitly extracted, the PDF structure and heuristics indicate a likely exploitation attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

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.xyz/app/835599320/tiktok-free-anime-websites-game-hack
    • https://kojak-group.com/userfiles/files/best-minecraft-hacked-client_GM479516143.pdf
    • https://kojak-group.com/userfiles/files/coin-master-cheat-engine-hack_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/pig-master-free-coins-and-spins_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/coin-master-daily-free-spins-link-today-2021_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/free-robux-discord_GM431946152.pdf
    • https://kojak-group.com/userfiles/files/coin-master-claim-free-spins_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/how-to-hack-coin-master-apple_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/coin-master-hack-september-2021_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/free-robux-no-human-verification-generator_GM431946152.pdf
    • https://kojak-group.com/userfiles/files/best-way-to-hack-coin-master_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/free-robux-kid-friendly-no-human-verification_GM431946152.pdf
    • https://kojak-group.com/userfiles/files/get-free-robux-generator_GM431946152.pdf
    • https://kojak-group.com/userfiles/files/make-your-own-minecraft-server-free_GM479516143.pdf
    • https://kojak-group.com/userfiles/files/coin-master-free-spins-and-coins-daily-links_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/coin-master-free-spins-link-october-2021_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/how-to-make-robux-on-roblox_GM431946152.pdf
    • https://kojak-group.com/userfiles/files/free-robux-hack-no-human-verification-or-survey_GM431946152.pdf
    • https://kojak-group.com/userfiles/files/coin-master-2021-free-spins_GM406889139.pdf
    • https://kojak-group.com/userfiles/files/free-robux-link_GM431946152.pdf
    • https://kojak-group.com/userfiles/files/coin-master-free-cards-link_GM406889139.pdf
    • http://en.wikipedia.org/wiki/MIT_License

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off00004b4a.bin
320cd903ecfc8a14b59a13910a53d1be41fbf4fe23c55ec67187516f7e29c521
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4B4A 28000 bytes
font_01_sfnt_off000089fa.bin
24ec6fe8bacad831e859931ef4a531848cace9557605aa44cf8e0bce48c9838c
pdf-font-stream PDF embedded font (sfnt) at offset 0x89FA 18072 bytes