Malicious PDF — malware analysis report

Static analysis result for SHA-256 1b3c71b7c5d81764…

MALICIOUS

PDF

34.9 KB Created: 2021-07-05 17:34:35 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-31
MD5: 5ca19d97d5bf05d08f1df0781fa1efe5 SHA-1: d38fa5bf662d743d6d39a36f01fc5c860f634f5e SHA-256: 1b3c71b7c5d817641d3a68c9f7afeaff83c070ff35a7e89b3837013eb3234a10
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple links to a malicious redirector hosted on 'netcdn.tw', disguised as game hacks and generators. It also includes numerous links to external PDFs, likely part of a link farm for SEO manipulation. The presence of these malicious links and the ML classifier's high confidence score indicate a clear intent to redirect users to potentially harmful content.

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.
  • 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.
  • 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.tw/app/431946152/robux-hack-free-robux-game-hack In PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/coin-master-free-spins-and-coins_GM406889139.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/free-robux-that-actually-works_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/free-coin-master-spins-for-today_GM406889139.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/coin-master-hack-2021-apk_GM406889139.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/mega-cheat-roblox_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/free-robux-no-verification_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/free-roblox-fan-shirt_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/how-to-take-free-robux_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/aimbot-hack-for-roblox-cbro_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/2021-free-promo-codes-roblox_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/is-minecraft-free_GM479516143.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/free-robux-no-verification-no-survey-2021_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/free-bear-face-mask-roblox_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/how-to-be-headless-in-roblox-free_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/how-to-get-cool-clothes-on-roblox-for-free_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/but-link-says-free-robux_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/free-robux-generator-without-verification_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/hacking-into-roblox-in-roblox-jailbreak-story_GM431946152.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/coin-master-daily-free-spins-link-today-2021_GM406889139.pdfIn PDF document text
    • https://digilib.widyagamahusada.ac.id/repository/how-to-hack-coin-master-using-es-file_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
font_00_sfnt_off000031cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x31CF 22500 bytes
SHA-256: f819e32d57b2efe3c71547da369c65a135e74b5302e27d175d90a45519c87194
font_01_sfnt_off000063d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x63D0 18884 bytes
SHA-256: 28c83382703d1552e66c4ba49065192da850ec7c15b1cba66d0a11ad7ce6efaa

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