Malicious PDF — malware analysis report

Static analysis result for SHA-256 91ffddc3630b299d…

MALICIOUS

PDF

43.4 KB Created: 2021-06-03 16:15:08 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-27
MD5: bf5c731d735ffb6e33f08f291d68de05 SHA-1: 565fa9a50fbac434a577f7c14ebea0261db096aa SHA-256: 91ffddc3630b299de6c27fa6b3787ecc5bef1f73fb7606433fcb5d6a28f6eac0
180 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 malicious redirector link, specifically pointing to 'https://netcdn.online/app/431946152/free-robux-com-real-game-hack'. This link is presented as a lure for a 'free generator / game hack', and the document body contains garbled text that includes this URL. The presence of a malformed exploit stream and ML classification further indicate malicious intent, likely to exploit vulnerabilities or deliver a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

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 https://netcdn.online/app/431946152/free-robux-com-real-game-hack In PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-spins-coin-master-links-2021_GM406889139.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/roblox-rape-hack_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/can-i-get-minecraft-for-free_GM479516143.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/how-to-get-free-robux-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-robux-quiz_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/coin-master-online_GM406889139.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/how-to-get-free-robux-generator_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/wurst-minecraft_GM479516143.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/coin-master-50-spin-link_GM406889139.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/coin-master-free-spins-coins_GM406889139.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-spins-coin-master-hack-2021_GM406889139.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/hack-coin-master-android-2021_GM406889139.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-robux-generator-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-private-minecraft-server_GM479516143.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/get-robux-now_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-robux-pastebin_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/oprewards-com-roblox_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-coin-and-spin-for-coin-master_GM406889139.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/free-admin-roblox_GM431946152.pdfIn PDF document text
    • https://www.andrology.co.uk/uploads/files/files/hack-coin-master-game-apk_GM406889139.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_004_off00004edc.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4EDC 24128 bytes
SHA-256: 0a9c48bd2ed428bf9c58bbdab341e4c6708f2ac280ec409480ad84c34f1961ef
font_01_sfnt_off00008603.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8603 18576 bytes
SHA-256: a83edd52c2be056a67ce389c2e3103e44ea5f6bc4cdf4c28a35d8553f09f80ba

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