Malicious PDF — malware analysis report

Static analysis result for SHA-256 777707a36d72e56d…

MALICIOUS

PDF

45.8 KB Created: 2021-05-16 16:12:48 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7)
MD5: 0e9d75a9832ea21ea5337a97e1aaa280 SHA-1: d171fd316e553db7b6a34d3794d75dc1fa4dccc5 SHA-256: 777707a36d72e56d30f0f90e92dc484cd53146e3219ab63dd246403092fec0df
102 Risk Score

Malware Insights

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

The document presents a fake CAPTCHA and a lure for 'free Robux' to trick users into clicking a malicious link. The ML classifier strongly indicates maliciousness, and the presence of external URIs suggests a download or redirection attempt. While no scripts were explicitly extracted, the PDF structure and heuristics point towards a social engineering attack designed to lead the user to a malicious website.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • 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.xyz/app/431946152/how-do-you-get-free-robux-without-paying-game-hack
    • http://citycare.pt/images/coin-master-15-free-spin-link-of-last-5-days_GM406889139.pdf
    • http://citycare.pt/images/free-spins-and-coins-coin-master-link-2021_GM406889139.pdf
    • http://citycare.pt/images/free-robux-not-a-scam_GM431946152.pdf
    • http://citycare.pt/images/free-premium-roblox_GM431946152.pdf
    • http://citycare.pt/images/free-links-coin-master_GM406889139.pdf
    • http://citycare.pt/images/roblox-comroblox_GM431946152.pdf
    • http://citycare.pt/images/free-robux-no-verification-needed_GM431946152.pdf
    • http://citycare.pt/images/how-to-get-free-robux-hack-2021_GM431946152.pdf
    • http://citycare.pt/images/free-roblox-accounts-2021_GM431946152.pdf
    • http://citycare.pt/images/robux-hack-2021_GM431946152.pdf
    • http://citycare.pt/images/blox-supply-free-robux_GM431946152.pdf
    • http://citycare.pt/images/my-minecraft-account-was-hacked_GM479516143.pdf
    • http://citycare.pt/images/hackear-coin-master-sin-root_GM406889139.pdf
    • http://citycare.pt/images/minecraft-reach-hack_GM479516143.pdf
    • http://citycare.pt/images/free-roblox-printables_GM431946152.pdf
    • http://citycare.pt/images/games-that-give-free-robux_GM431946152.pdf
    • http://citycare.pt/images/mobihack-roblox-hack_GM431946152.pdf
    • http://citycare.pt/images/roblox-shirt-template-free_GM431946152.pdf
    • http://citycare.pt/images/coin-master-hack-spins-free_GM406889139.pdf
    • http://citycare.pt/images/best-site-for-free-coin-master-free-spins_GM406889139.pdf
    • http://en.wikipedia.org/wiki/MIT_License

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off00004baf.bin
bce403eced6e420c7099579c96f813227c71816cfaf0e7a3adfc9f1076348262
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4BAF 28552 bytes
font_01_sfnt_off00008bfc.bin
5d1001e3ac77277796354ae1628373f4f4a3ba3fa344903a86c4555bafe1b783
pdf-font-stream PDF embedded font (sfnt) at offset 0x8BFC 19948 bytes