Malicious PDF — malware analysis report

Static analysis result for SHA-256 c91221d07f9fcd9f…

MALICIOUS

PDF

44.2 KB Created: 2021-06-13 20:41:53 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 21755b1c2a01c9ecaa2c7d1d84aa0a7e SHA-1: 47efc9c703e7435003078f5655529da683269742 SHA-256: c91221d07f9fcd9f0bb093d50e317f70047166179cdab25b15913c40f9e78e17
240 Risk Score

Malware Insights

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

This PDF document contains numerous links to external resources, including a malicious redirector at http://netcdn.co/app/431946152/free-redvalk-code-roblox-news-game-hack. The document's content and heuristics indicate it is designed to lure users into clicking these links, likely leading to further malicious content or exploits. The malformed stream length suggests an attempt to hide malicious code.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • 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.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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-redvalk-code-roblox-news-game-hack In PDF document text
    • http://library.umla.ac.id//repository/how-do-i-get-minecraft-for-free_GM479516143.pdfIn PDF document text
    • http://library.umla.ac.id/repository/robux-hack-generator-com_GM431946152.pdfIn PDF document text
    • http://library.umla.ac.id/repository/free-coins-coin-master-link-2021_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id//repository/how-to-earn-free-pokeballs-in-pokemon-go_GM1094591345.pdfIn PDF document text
    • http://library.umla.ac.id//repository/coin-master-free-coin-hack_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id//repository/coin-master-get-free-cards_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id/repository/minecraft-life-hacks_GM479516143.pdfIn PDF document text
    • http://library.umla.ac.id/repository/how-to-get-free-robux-without-downloading-any-apps_GM431946152.pdfIn PDF document text
    • http://library.umla.ac.id/repository/free-robux-on-phone_GM431946152.pdfIn PDF document text
    • http://library.umla.ac.id//repository/80-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id/repository/free-spin-link-for-coin-master_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id/repository/coin-master-free-spin-link-app_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id//repository/roblox-avatar-editor-free_GM431946152.pdfIn PDF document text
    • http://library.umla.ac.id//repository/minecraft-fly-hack_GM479516143.pdfIn PDF document text
    • http://library.umla.ac.id//repository/coin-master-free-spins-link-2021-april_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id/repository/toolbox-mod_GM479516143.pdfIn PDF document text
    • http://library.umla.ac.id/repository/how-to-get-robux-with-cheat-engine-63_GM431946152.pdfIn PDF document text
    • http://library.umla.ac.id/repository/coin-master-free-spins-2021-ios_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id/repository/coin-master-hack-tool-no-survey_GM406889139.pdfIn PDF document text
    • http://library.umla.ac.id/repository/free-robux-generator-no-human-verification_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
stream_003_off00004b84.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4B84 26796 bytes
SHA-256: ab45abf1c8745ad8d5c32e97e2570ac4d1e52487f4ab17e3102bc9cacd211919
font_01_sfnt_off000088bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x88BC 18800 bytes
SHA-256: 5033ec437e0f1d6d3ca225540d1ef52499eee824a4a7aace8644c05dc5a8a795

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