Malicious PDF — malware analysis report

Static analysis result for SHA-256 a599423be28e10fd…

MALICIOUS

PDF

33.5 KB Created: 2021-07-19 10:31:06 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: cea1c149944e6777a147a4d42b299eec SHA-1: 4d52978fb5ff3dc3f9bcf07e8f41f3f5c559292c SHA-256: a599423be28e10fd56e759d4bdcd20ae0298cf1153b1a23c281380a6aca7a78f
180 Risk Score

Malware Insights

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

The PDF contains a malformed stream and links to known malicious redirector infrastructure, specifically http://netcdn.tw/app/431946152/free-robux-codes-2021-game-hack. The document body and embedded links suggest a lure for "free Robux" or "game hacks", likely intended to trick users into downloading further malware or visiting phishing sites. The ML classifier also flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9767

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.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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/431946152/free-robux-codes-2021-game-hack In PDF document text
    • https://elearning.mtsnkarimun.sch.id/__statics/gudangsoal/files/huskybuckscom-free-robux_GM431946152.pdfIn PDF document text
    • https://elearning.mtsnkarimun.sch.id/__statics/gudangsoal/files/free-tiktok-followers-no-survey_GM835599320.pdfIn PDF document text
    • https://elearning.mtsnkarimun.sch.id/__statics/gudangsoal/files/get-free-robux-2021_GM431946152.pdfIn PDF document text
    • https://elearning.mtsnkarimun.sch.id/__statics/gudangsoal/files/free-tiktok-views-no-verification_GM835599320.pdfIn PDF document text
    • https://elearning.mtsnkarimun.sch.id/__statics/gudangsoal/files/roblox-hack-com_GM431946152.pdfIn PDF document text
    • https://elearning.mtsnkarimun.sch.id/__statics/gudangsoal/files/minecraft-gun-games-free_GM479516143.pdfIn PDF document text
    • https://www.roblox.com/.IIn 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_off00002c70.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2C70 22868 bytes
SHA-256: 52993b44d23276cb5fca8a4f404a952f4f8888668f0dd81aba6fd61c7cbd5029
font_01_sfnt_off00005fc2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5FC2 18776 bytes
SHA-256: 86719edcafa38007f3fc56311acd0ad5bd2c3683937e8590d35305e3fc241c35

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