Malicious PDF — malware analysis report

Static analysis result for SHA-256 a21f16a198073992…

MALICIOUS

PDF

31.3 KB Created: 2021-07-22 07:56:48 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: a241dd864fd3b6eb4f4e3d3392f30d1b SHA-1: 8eb7cabadaa20039a0deace8c5fbc58b9e80d84b SHA-256: a21f16a1980739924432cc1c8235834c0d63e2123a47c330df53ef0b9eb2f077
130 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for a redirector lure, specifically linking to a 'coin master free spins' generator. This link, http://netcdn.tw/app/406889139/coin-master-free-spins-link-2021-today-game-hack, is known to be malicious. The document body and embedded artifacts suggest an attempt to trick the user into clicking the link, likely to download a second-stage payload.

Machine Learning

  • Nyx PDF Classifier clean score 0.0580

Heuristics 4

  • 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.
  • 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 http://netcdn.tw/app/406889139/coin-master-free-spins-link-2021-today-game-hack In 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
font_00_sfnt_off00002424.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2424 22816 bytes
SHA-256: bdca4f820c0c0aa39c670d9be41cd5e0044a643f094db433aceb2b0cec378b34
font_01_sfnt_off00005725.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5725 18812 bytes
SHA-256: 705c5903f824403b328e8e9dbd2ab52a650d097fc3c0d4bbd34be772086d041a