Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c28d150b419ef0d…

MALICIOUS

PDF

48.8 KB Created: 2021-06-09 09:37:08 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-16
MD5: fbcfa618e9738d546886861498b3c697 SHA-1: e3383365076e36df21ef0a6e6f4cc6032201dfd2 SHA-256: 4c28d150b419ef0d33a487002cbb25786fc54d55c9a4c1adf3162c00bd7a31e6
122 Risk Score

Malware Insights

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

The PDF document contains numerous links to external websites, many of which are hosted on sbm-nn.ru and appear to be SEO-optimized pages for game cheats and hacks. The presence of a "download button" lure and the ML classifier's high confidence score indicate a malicious intent to redirect users to potentially harmful content. The document body, though heavily obfuscated, contains references to "Roblox Free Robux" and game hacks, reinforcing the lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9871

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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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-free-robux-pastebin-javascript-game-hack PDF link annotation
    • http://sbm-nn.ru/images/play-coin-master-for-free_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-roblox-followers_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/robux-matchcomfree-robux_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/roblox-phantom-forces-hack-aimbot_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-hack-spins-app_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-daily-free-spins-link-facebook_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/best-way-to-get-robux_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/blox-piece-roblox-hack_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-robuxs-free_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/roblox-earn-robux_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/minecraft-hack-download_GM479516143.pdfIn PDF document text
    • http://sbm-nn.ru/images/free-printable-minecraft-coloring-pages_GM479516143.pdfIn PDF document text
    • http://sbm-nn.ru/images/farming-simulator-hack-roblox-script_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-to-hack-roblox-accounts-on-phone_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/daily-coin-master-free-spins_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-hack-for-android_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-to-make-robux_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/coin-master-hack-2021-no-human-verification_GM406889139.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-to-get-a-free-skin-roblox-avatar_GM431946152.pdfIn PDF document text
    • http://sbm-nn.ru/images/how-to-play-minecraft-for-free-on-pc_GM479516143.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_off000050d9.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x50D9 32724 bytes
SHA-256: e02e00e087681f28063951b0c074a64f4f7d7b5421d3174e824b18fd4191c1b7
font_01_sfnt_off000099de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x99DE 19148 bytes
SHA-256: 86c8b8da43f564db0d8e338d7d931a4ecbc4636cbb5c70fbcb6a72f613f414cf

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