Malicious PDF — malware analysis report

Static analysis result for SHA-256 037161c1e66184d7…

MALICIOUS

PDF

34.7 KB Created: 2021-06-18 04:54:45 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 18f2206ee7dbd2b037edad5bec0f1224 SHA-1: 6a8a79395a315147155bd7dd757865a8bbfc4059 SHA-256: 037161c1e66184d76265b2755e039f2f6d136f0eae69f066307cda3a650a2f93
180 Risk Score

Malware Insights

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

The PDF contains malformed streams and links to known malicious redirectors, specifically advertising 'free Robux' and 'game hacks'. The ML classifier strongly indicates maliciousness. While no scripts were directly extracted, the malformed stream suggests an attempt to exploit PDF vulnerabilities, likely to redirect the user to malicious sites or download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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.co/app/431946152/free-robux-ad-2021-game-hack In PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/how-to-hack-a-minecraft-server_GM479516143.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/how-to-get-free-robux-on-chromebook_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/how-to-get-free-premium-roblox_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/robux-hacks-2021_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/daily-coin-master-free-spin-apk_GM406889139.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/free-links-to-coin-master_GM406889139.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/roblox-land-free-robux_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/free-robux-human-verification_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/roblox-script-executor-free_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/client-minecraft_GM479516143.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/minecraft-free-app_GM479516143.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/free-robux-generator-without-human-verification_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/clients-minecraft_GM479516143.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/is-minecraft-free-on-ps4_GM479516143.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/minecraft-bedrock-free-with-java_GM479516143.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/how-to-use-cheat-engine-on-roblox-without-shutdown_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/how-can-i-get-free-spins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/coin-master-cheats-2021_GM406889139.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/how-to-get-free-robux-website_GM431946152.pdfIn PDF document text
    • http://hosoffices.com/ckfinder/userfiles/files/get-free-robux-today_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
font_00_sfnt_off00003110.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x3110 22212 bytes
SHA-256: 41f03d728e92f490aeed482b9b1fdb57886814a526f5a50656e5fadfc88cf999
font_01_sfnt_off00006264.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6264 19104 bytes
SHA-256: c39503094e004c7f2ea4f05bf3c95ab80a2fefd42e9613099f8be5a766bdffd9

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