Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef43559ef35579c7…

MALICIOUS

PDF

40.6 KB Created: 2021-06-10 22:56:30 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 992554591b38386f4081f3580da7e82c SHA-1: 81087c8018d60fb7f971be8089933d5b2e84cc85 SHA-256: ef43559ef35579c7e2d12df50e07134f994c7cdbe920c81ad083185655cb4c2f
170 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1505.003 Server Software Component: Exploit Public-Facing Application

The PDF file contains a critical heuristic indicating it links to a malicious redirector disguised as a game hack generator. The document body and embedded artifacts further support this, with explicit mentions of 'free Robux' and a call to action to access a generator. The presence of a security bypass instruction is a strong indicator of malicious intent, aiming to prevent detection.

Machine Learning

  • Nyx PDF Classifier clean score 0.0353

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.
  • Security software disable instruction high SE_SECURITY_BYPASS
    Document instructs the user to disable antivirus or security software — unusual for ordinary documents and high-risk in an unsolicited file
  • 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.tw/app/431946152/how-to-get-free-robux-no-hack-or-cheat-2021-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
stream_004_off00003ee8.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x3EE8 25500 bytes
SHA-256: f0260f38cc7ccdf53c12b2eb6444915efc0dd4ea23e265e12866144c0bc3edd8
font_01_sfnt_off00007a48.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7A48 19248 bytes
SHA-256: 92c703c58c85fd83d67cafcf0a4b50639f5df26b6291f4046c94ea64a180bfd9

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