Malicious PDF — malware analysis report

Static analysis result for SHA-256 5d941925d344700d…

MALICIOUS

PDF

45.2 KB Created: 2021-06-11 12:24:14 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 256f066d60c36863ca7a0d42ca2c6212 SHA-1: 6732f09de514d1e75de8bc6f4f086fb4983b8e34 SHA-256: 5d941925d344700d0406d868a13f4652173be1532145e661481dee5f8516d166
162 Risk Score

Malware Insights

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

The PDF contains numerous links to external sites, many of which are hosted on kukuck.de and appear to be part of a link farm designed to attract users searching for game cheats and hacks. The presence of a fake CAPTCHA heuristic suggests an attempt to trick users into further interaction, likely leading to malicious downloads or phishing. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9864

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.
  • 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
  • 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/premium-membership-hack-on-roblox-game-hack PDF link annotation
    • http://kukuck.de/images/cheats-for-ninja-legends-roblox_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/free-builders-club-roblox-trial_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/minecraft-free-download-iphone_GM479516143.pdfIn PDF document text
    • http://kukuck.de/images/free-robux-hacker-us_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/how-to-hack-coin-master_GM406889139.pdfIn PDF document text
    • http://kukuck.de/images/today-coin-master-spin-free_GM406889139.pdfIn PDF document text
    • http://kukuck.de/images/how-to-get-free-robux-with-no-verification_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/roblox-generator-no-verification_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/coin-master-free-spins-and-coins-link-haktuts_GM406889139.pdfIn PDF document text
    • http://kukuck.de/images/free-robux-free-and-easy_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/hackear-coin-master-espaol_GM406889139.pdfIn PDF document text
    • http://kukuck.de/images/free-robux-offers_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/roblox-codes-for-cheat-engine_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/roblox-sexually_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/how-to-hack-someone-in-roblox-using-captra_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/how-to-hack-roblox-accounts-on-a-phone_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/noclip-hack-download-for-roblox_GM431946152.pdfIn PDF document text
    • http://kukuck.de/images/free-spins-on-coin-master-hack_GM406889139.pdfIn PDF document text
    • http://kukuck.de/images/how-to-get-minecraft-bedrock-for-free-with-java_GM479516143.pdfIn PDF document text
    • http://kukuck.de/images/how-to-get-free-robux-without-downloading-apps-2021_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off00005229.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5229 24800 bytes
SHA-256: 62d4bfd87a6ef351cbf62e116dc898a4c3824ff17a8a33ab1a513ef4af031c60
font_01_sfnt_off00008b33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8B33 19392 bytes
SHA-256: b7685f8ae0799ec778e7a3373dd0a5435e3c2e32da0bf2176d7ccc0653e0bd32

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