Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f665ed6187a8f7…

MALICIOUS

PDF

43.6 KB Created: 2021-05-15 09:51:17 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: d83211cf4acad3203929b2a97c3eb3a0 SHA-1: 411115967f4628daf16c9b7d281d8abc8eafe001 SHA-256: 81f665ed6187a8f773bd5767ffae0b1d8b500ec1d80f9d2c638d6928330d1b6e
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF document was flagged as malicious by an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, routes users through malicious redirector infrastructure and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9648

Heuristics 5

  • 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.
  • PDF links to a 'free generator / game hack' redirector high 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.
  • 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
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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.xyz/app/406889139/card-hack-for-coin-master-game-hack PDF link annotation
    • http://krumerhaus.at/images/safe-hack-for-coin-master-android_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/free-robux-2021-no-human-verification_GM431946152.pdfIn PDF document text
    • http://krumerhaus.at/images/how-do-we-get-free-robux_GM431946152.pdfIn PDF document text
    • http://krumerhaus.at/images/free-spin-app-for-coin-master_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/coin-master-blogspot_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/roblox-com-games-referrer-roblox-player_GM431946152.pdfIn PDF document text
    • http://krumerhaus.at/images/free-robux-codes-2021_GM431946152.pdfIn PDF document text
    • http://krumerhaus.at/images/best-free-minecraft-texture-packs_GM479516143.pdfIn PDF document text
    • http://krumerhaus.at/images/coinmaster-fan-page_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/haktuts-free-spins_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/easy-roblox-today_GM431946152.pdfIn PDF document text
    • http://krumerhaus.at/images/free-robux-master_GM431946152.pdfIn PDF document text
    • http://krumerhaus.at/images/spin-free-coin-master_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/can-you-give-me-free-robux_GM431946152.pdfIn PDF document text
    • http://krumerhaus.at/images/coin-master-free-spins-reddit_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/wwwcoin-master-hack-game-download_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/free-spins-and-coins-coin-master-facebook_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/coin-master-free-coins-and-spins-2021_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/coin-master-free-spin-link-app_GM406889139.pdfIn PDF document text
    • http://krumerhaus.at/images/robux-com-free_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off00004859.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4859 24212 bytes
SHA-256: 9e92780045ab795ae7eeb1151607bf8dbda9b58914ad895b7ce8697231f0f7f5
font_01_sfnt_off00007f0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7F0D 2824 bytes
SHA-256: 381f6d859be141449dd645f7be1484d2a1cf49218dc471b402dae69eaa2b11d5
font_02_sfnt_off000088b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x88B0 18056 bytes
SHA-256: 16c04f841c276c9143b9cdeba32c018779ebf720d5ca55aa256a698217b90b2b

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