Malicious PDF — malware analysis report

Static analysis result for SHA-256 c31c8dda063967be…

MALICIOUS

PDF

77.7 KB Created: 2021-09-09 04:56:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: e272708ff820c98c87a741fc613f8f94 SHA-1: db5563251e463cdc95cf374144cf83a656c01e11 SHA-256: c31c8dda063967be1edc987177ab7063162f0fdd2d1d69448bd8c1f5e770135f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates it functions as a link farm, directing users to multiple distinct hosts, which is a common tactic for phishing or malware distribution. While no scripts were explicitly extracted, the nature of the link farm and the malicious verdict suggest it likely leads to a malicious site or payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://namdolove.com/FileData/ckfinder/files/20210909_D89C15CF39A8595B.pdf In PDF document text
    • https://joinvita.com/neu/userfiles/file/89162445488.pdfIn PDF document text
    • http://vizugy.hu/uploads/files/499308910.pdfIn PDF document text
    • http://oskarmak.com/userfiles/file/volofobusobaf.pdfIn PDF document text
    • https://n-vv.dk/userfiles/file/67812716670.pdfIn PDF document text
    • https://irish-setter-zucht.info/ckfinder/userfiles/files/vadakifajomeri.pdfIn PDF document text
    • https://self-storage.sg/images/uploadedimages/file/52293266767.pdfIn PDF document text
    • http://etalentlink.com/uploadfile/file///2021090105482340.pdfIn PDF document text
    • http://tcsm62.org/uploads/news/file/45520127871.pdfIn PDF document text
    • http://fujiya-la.com/uploads/files/86448695260.pdfIn PDF document text
    • http://multiflex.ru/userfiles/file/81732725156.pdfIn PDF document text
    • http://daindnc.com/fckeditor/userfiles/file/48938267570.pdfIn PDF document text
    • http://manenshop.com/upload/files/pevetevepitanikugepujab.pdfIn PDF document text
    • http://laulumaja.fi/ckfinder/userfiles/files/61550301306.pdfIn PDF document text
    • https://aymfly.com/aym_image/files/paxujobewuzodofon.pdfIn PDF document text
    • http://centrlita.ru/archive/image/file/gupax.pdfIn PDF document text
    • http://robwalker.net/fckupload/file/61649042418.pdfIn PDF document text
    • http://laxycoffee.com/upload/files/sagomow.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=qual+a+vers%C3%A3o+mais+atualizada+do+androidPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c788.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC788 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000df9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF9A 18796 bytes
SHA-256: 0005f14d03a09487bafce98fce2f682153feb1e1119d1c4975a6937e0290b885
font_02_sfnt_off00010dfb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DFB 10960 bytes
SHA-256: af02c43a161339464c4b96278b5faeed990313009ff7373b0d57893fe3867d47

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