Malicious PDF — malware analysis report

Static analysis result for SHA-256 5f1f43e5b7f5b6e1…

MALICIOUS

PDF

34.2 KB Created: 2021-06-19 03:35:52 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-26
MD5: 5413e0873772ffd7dbc7464148d4ca75 SHA-1: d834aefd936cc3719295e148ffac0cfa84f53922 SHA-256: 5f1f43e5b7f5b6e1c6ed8d0ab788b2edd6f2173c8425e86be16895c525bab65d
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a malformed stream and links to known malicious redirectors, specifically advertising "free Robux" or "game hacks" to entice clicks. The primary malicious URL identified is http://netcdn.co/app/431946152/free-robux-without-human-verification-and-no-survey-game-hack. The ML classifier strongly indicated maliciousness, and the document body reinforces the lure.

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-without-human-verification-and-no-survey-game-hack In PDF document text
    • http://lib.untad.ac.id/repository/free-spins-and-coins-blogspot-coin-master_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id//repository/free-face-roblox_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/coin-master-free-link-daily_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/coin-master-hack-2021-iphone_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/roblox-robux-hack-club_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/coin-master-hack-online-download_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/free-robux-sites-2021_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id//repository/blogspot-coin-master-free-spins_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/fly-hack-download-for-roblox-survivor_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id//repository/how-to-host-a-minecraft-server-for-free_GM479516143.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/free-coins-coin-master_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/get-free-lives-on-coin-master_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/roblox-robort-free_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id//repository/free-robux-generator-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id//repository/games-that-give-you-free-robux_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id//repository/free-robux-no-offers_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id//repository/como-hackear-coin-master_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/static-moonactive-net_GM406889139.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/www-robux_GM431946152.pdfIn PDF document text
    • http://lib.untad.ac.id/repository/robux-hack-free-robux_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_off00002e0a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2E0A 21600 bytes
SHA-256: 3811e226ea81b66142f2a47ff7b69f226427726401c7b8037cdbdc76d6a9bc82
font_01_sfnt_off00005d53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5D53 20164 bytes
SHA-256: 3e91c75ddc5bc63aff6ea61db212115ffeab2bc45a3cd968753c78fdb07aee39

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