Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4bcf66de55e8768…

MALICIOUS

PDF

43.4 KB Created: 2021-05-19 18:01:13 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-25
MD5: 3499822675dbb105c46c2fce78f0b067 SHA-1: 6c572ce7344ae367449055a3494ec980aa2880dd SHA-256: b4bcf66de55e87682da9c9c0104929eceee3adb94871e94cb2c4bdc5d7b4b5b8
202 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by an ML classifier. It uses a callback-phone (TOAD) lure and a fake-CAPTCHA lure. The file embeds a large number of external links characteristic of an SEO link farm, routes users through malicious redirector infrastructure and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

Heuristics 7

  • 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.
  • PDF links to a 'free generator / game hack' redirector high 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.
  • 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-to-free-robux-game-hack PDF link annotation
    • http://precitool.ch/images/getrobux-info_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/free-spins-coins-coin-master_GM406889139.pdfIn PDF document text
    • http://precitool.ch/images/how-to-get-free-robux-easy_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/hack-coin-master-apk-358_GM406889139.pdfIn PDF document text
    • http://precitool.ch/images/how-to-get-free-roebucks-in-roblox_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/minecraft-kill-aura_GM479516143.pdfIn PDF document text
    • http://precitool.ch/images/coin-master-free-coins-link-2021_GM406889139.pdfIn PDF document text
    • http://precitool.ch/images/coin-master-daily-free-spins-link-today-facebook_GM406889139.pdfIn PDF document text
    • http://precitool.ch/images/offers-to-complete-and-get-free-spins-in-coin-master_GM406889139.pdfIn PDF document text
    • http://precitool.ch/images/how-to-get-free-robux-without-email_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/coin-master-free-link-today_GM406889139.pdfIn PDF document text
    • http://precitool.ch/images/free-roblox-boy-hair_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/mcpe-master-hack-unlimited-coins-apk_GM406889139.pdfIn PDF document text
    • http://precitool.ch/images/earn-robux-websites_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/roblox-tix-generator_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/minecraft-free-download-no-virus_GM479516143.pdfIn PDF document text
    • http://precitool.ch/images/how-to-get-robux-on-roblox_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/how-to-hack-roblox-accounts-for-robux_GM431946152.pdfIn PDF document text
    • http://precitool.ch/images/how-to-get-minecraft-for-free-on-iphone-2021_GM479516143.pdfIn PDF document text
    • http://precitool.ch/images/can-you-get-minecraft-for-free_GM479516143.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_003_off00004c2e.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4C2E 25876 bytes
SHA-256: edaeb16a1d4d0b3f98739d3002aeddaea8816dd3bd9207642615da81371daa00
font_01_sfnt_off000087ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x87CA 18180 bytes
SHA-256: b892188b0545c7b74f3e706ff7289536b8608c6e24b963a14dda60cd6c46c02c

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