Malicious PDF — malware analysis report

Static analysis result for SHA-256 51c3c69985db7fe3…

MALICIOUS

PDF

36.4 KB Created: 2021-05-20 15:19:37 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-24
MD5: a8e22e4a7c34d897ede1c95fda0d31c3 SHA-1: c9b00e103d11389e3f344bbfca3c82ab08719ae6 SHA-256: 51c3c69985db7fe3cd57ec5bee789daed860758151cfd50984bf9d3b633b8f36
200 Risk Score

Malware Insights

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

The PDF document contains a lure for free Robux and displays a fake CAPTCHA, aiming to deceive users into clicking malicious links. The embedded links redirect to known malicious infrastructure, suggesting an attempt to lead users to phishing sites or download malware. While no scripts were explicitly extracted, the PDF structure and heuristics indicate a malicious redirector workflow.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9492

Heuristics 5

  • PDF links to a 'free generator / game hack' redirector critical PDF_GAME_HACK_REDIRECT_LURE
    PDF's clickable action targets a redirector of the form /app/<id>/<slug>-game-hack — the landing-page shape of a large SEO 'free spins / generator / game hack' lure family that funnels victims through rotating disposable hosts to a malware/scam payload. The multi-link variants also trip ML/link-farm rules; this catches the single-link variants that otherwise score clean. CRITICAL on its own: the /app/<id>/<slug>-game-hack path shape is unambiguous scam infra, and the host rotates so a host-list match can't be relied on.
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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
  • 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-to-get-free-robux-easy-2021-game-hack In PDF document text
    • http://www.gearestauri.it/images/coin-master-cards-for-free_GM406889139.pdfIn PDF document text
    • http://www.gearestauri.it/images/free-minecraft-client_GM479516143.pdfIn PDF document text
    • http://www.gearestauri.it/images/free-robux-no-verification-no-survey_GM431946152.pdfIn PDF document text
    • http://www.gearestauri.it/images/free-robux-generator-com-roblox-hack_GM431946152.pdfIn PDF document text
    • http://www.gearestauri.it/images/op-rewards-robux_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off000030c1.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x30C1 24892 bytes
SHA-256: 2f5ee7912438ba6bdad2573784c7afa4f39cf80061b4797c41bd8f361bbf56b6
font_01_sfnt_off00006a29.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6A29 19092 bytes
SHA-256: b4f5bd8c8985fe06cb8cafea7c6a35db41ab3230d9b691422e9309a9df735677

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