Malicious PDF — malware analysis report

Static analysis result for SHA-256 621db6783ae79753…

MALICIOUS

PDF

34.3 KB Created: 2021-06-23 03:46:51 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-16
MD5: 428c5e5b9519af11321c2821abe1ed13 SHA-1: 1b8ba4e07723e5f221ee202188972ee0f06a3322 SHA-256: 621db6783ae79753a7bbba4c16fc1d9ce34e0c9aba9abc5097b746330bb17a9d
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF document contains a large number of external links, many of which point to other PDF files hosted on the same domain. This behavior is indicative of a link farm or SEO manipulation tactic, potentially used to distribute malicious content or pages. The ML classifier strongly flagged this PDF as malicious, and the presence of numerous external links, including one to 'netcdn.co', suggests a high likelihood of malicious intent. No scripts were extracted, but the document's structure and link farm characteristics are sufficient to infer a malicious purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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 http://netcdn.co/app/406889139/spin-link-coin-master-game-hack PDF link annotation
    • https://limebug.com/media/storage/editor/files/free-apk-mods-coin-master_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/coin-master-unlimited-spin-link_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/how-to-hack-people-on-roblox_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/how-do-you-get-free-robux-without-doing-anything_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/roblox-free-roam-games-grand-blox_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/roblox-toy-codes-free_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/mobihack-roblox-hack_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/free-spins-for-coin-master-game_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/coin-master-free-spins-link-2021-download_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/freespinandcoinblogspotcom-2021-11-coinmasterfreespinandcoinlinkshtml_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/free-spins-coins-coin-master_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/how-can-you-get-robux_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/coin-master-hack-100-working_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/daily-coin-master-free_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/get-free-robux_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/flame-gg-free-robux_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/coin-master-free-spins-through-coin-pop_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/free-links-for-coin-master_GM406889139.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/how-to-hack-roblox-accounts-2021_GM431946152.pdfIn PDF document text
    • https://limebug.com/media/storage/editor/files/roblox-com-free-robux_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
font_00_sfnt_off00003010.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x3010 22960 bytes
SHA-256: 0a4c811f2489f642a830a6b7f7731d1179d4f1cd3beddc751fa0ac151063b0de
font_01_sfnt_off00006393.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6393 18180 bytes
SHA-256: 8cec956f0aa344b71c49253e3a1960d7050c35fa3eda1dd756b741f549247ffc

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