Malicious PDF — malware analysis report

Static analysis result for SHA-256 a73c5055cbdf96e8…

MALICIOUS

PDF

48.5 KB Created: 2021-06-09 14:59:17 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: f557d83f13ee3c9e041d47314963d651 SHA-1: 8116934658bc6659e73704e8a9d5d402461ee1cf SHA-256: a73c5055cbdf96e8d9e77de33322cd27f530a3aa9d74ef64216cbfe837628262
142 Risk Score

Malware Insights

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

This PDF document contains a large number of external links, many of which are disguised as game hacks or generators for popular games like Roblox and Coin Master. The primary heuristic indicates a 'PDF SEO Link Farm', suggesting the document is designed to drive traffic to these potentially malicious sites. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9796

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.tw/app/431946152/free-roblox-places-download-game-hack PDF link annotation
    • http://library.ulb.ac.id//repository/coin-master-hack-mod-apk_GM406889139.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/robuxlove-net-free-robux_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/download-roblox-for-free-on-chromebook_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/tiktok-free-50-likes_GM835599320.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/games-like-minecraft-but-free_GM479516143.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/how-to-get-free-robux-for-kids_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/can-pokemon-go-free-evolve-after-trade_GM1094591345.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/roblox-hack-atravesar-paredes_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/roblox-free-wings_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/coin-master-32-mod-hack-apk-download_GM406889139.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/roblox-hack-ios_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/do-you-get-minecraft-windows-10-for-free_GM479516143.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/coin-master-hacks-for-pet-food_GM406889139.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/free-cracked-minecraft-server-hosting_GM479516143.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/coin-master-free-500-spins-link_GM406889139.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/coin-master-collect-today-free-spin_GM406889139.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/free-draw-2-roblox_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id//repository/how-to-get-free-robux-on-ipad_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/ways-to-earn-robux_GM431946152.pdfIn PDF document text
    • http://library.ulb.ac.id/repository/get-free-spins-on-coin-master-no-human-verification_GM406889139.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_004_off00005063.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5063 27484 bytes
SHA-256: cf451ce30d90a9456868e404f526316b7f1632420cc3d9e1b3f0755737b7f4db
font_01_sfnt_off00008de0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8DE0 3400 bytes
SHA-256: 4b3e0f36ad1e0c7e3ea5c178fd2b4f097d1e01575fc6a4101a8b520db34dfe07
font_02_sfnt_off00009909.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9909 18836 bytes
SHA-256: 0d05596c723a80ba8c8c20be1315fad49299a9175322038faa893f71aafd1104

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