Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbff657da7d888d3…

MALICIOUS

PDF

45.9 KB Created: 2021-06-08 22:31:12 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 93de00ffee6a5c5d49a09fab074ac11e SHA-1: 77451625b640d17445aa0d72f05a2d08d372c416 SHA-256: cbff657da7d888d3cd4b5a26b1f69de1fc5a81991617dc205f8aeb231ecb946d
142 Risk Score

Malware Insights

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

The PDF contains multiple heuristics indicating it is a lure for game hacks, specifically mentioning 'Roblox Hack Mod Unlimited Robux'. It links to external URLs that are likely part of a redirector chain or host malicious content. The ML classifier also flagged this PDF as malicious with high confidence. While no scripts were explicitly extracted, the PDF structure and embedded links suggest an attempt to redirect users to a malicious site, potentially for credential harvesting or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9864

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/roblox-hack-mod-unlimited-robux-game-hack PDF link annotation
    • http://elib-s2.ubl.ac.id/repository/how-to-get-free-robux-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/how-can-you-get-free-robux_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/robux-free-c_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/minecraft-apk-download-v1-144-2-free_GM479516143.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/how-to-get-robux-for-free-2021_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/minecraft-pe-015-0-apk-free-download_GM479516143.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/how-do-i-get-free-spins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/free-minecraft-mods_GM479516143.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/how-to-get-free-robux-codes_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/minecraft-java-edition-free-download-for-android_GM479516143.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/free-robux-without-downloading-apps_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/free-tiktok-fans-no-human-verification-or-downloading-apps_GM835599320.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/free-robux-giveaway-live-now-2021_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/free-robux-generator-no-human-verification_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/free-spin-link-for-coin-master_GM406889139.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/coin-master-spin-free_GM406889139.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/coin-master-heaven-free-spins_GM406889139.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/how-to-get-free-tiktok-coins_GM835599320.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/robuxy-com-free-robux_GM431946152.pdfIn PDF document text
    • http://elib-s2.ubl.ac.id/repository/free-robux-hack_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_004_off000050d1.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x50D1 27008 bytes
SHA-256: c6dc80e4e3e4894de10b7ff586ac366c47be75fdf253078a1c62157d6c6a4ec9
font_01_sfnt_off00008d8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8D8C 19360 bytes
SHA-256: f5105d8bbfd2dfd7534ae293eb30ac0f76a8bb89d446187f56d244925f34d47b

Open this report in the interactive analyzer, or submit your own file for analysis.