Malicious PDF — malware analysis report

Static analysis result for SHA-256 7f762e3cd09479f2…

MALICIOUS

PDF

79.1 KB Created: 2021-09-10 23:16:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 941da5e36d8834a7f3626afa5a2012ff SHA-1: 69846d72e08310241ca29b2760c3ece5a59476d5 SHA-256: 7f762e3cd09479f263cac6ec2b63b31270730c7b63c435841273de04d425fd9f
126 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ClamAV as a phishing trojan and by an ML classifier. It contains numerous embedded URLs, many of which point to PDF files hosted on various domains, suggesting a link farm or SEO abuse. The 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic confirms this, noting a high number of distinct hosts and a redirector pattern. While no scripts were extracted, the overall structure and heuristics indicate a malicious intent to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://andrejc.si/files/file/dojasudujibenokagekim.pdf In PDF document text
    • http://pataibicaj.hu/userfiles/file/jalav.pdfIn PDF document text
    • https://braindevelopmentmaps.org/userfiles/files/bodafigasosupovi.pdfIn PDF document text
    • http://stroykap.com/application/views/stroykap/userfiles/file/dumujiwejupobew.pdfIn PDF document text
    • http://toitureetfacade.fr/data/Files/27652792139.pdfIn PDF document text
    • http://jagatjyotischool.org/jagatjyotischool/userfiles/file/rifukitajenuvidekasonek.pdfIn PDF document text
    • http://kangshi-you.com/uploads/files/202109102304347586.pdfIn PDF document text
    • http://nirmalapublicschoolerumely.com/userfiles/file/17356923058.pdfIn PDF document text
    • http://zaiger.ru/img/file/sodumemusaziw.pdfIn PDF document text
    • http://dongsimkindergarten.com/upload/files/wufobu.pdfIn PDF document text
    • https://episcopiaoradiei.ro/files/zefuno.pdfIn PDF document text
    • http://tinavaron.com/ckfinder/userfiles/files/pepawo.pdfIn PDF document text
    • http://www.accl-calibration.com/login/ckfinder/userfiles/files/sakazenubuxisuwagafaruza.pdfIn PDF document text
    • http://colorfulmedia.de/fotki/fotki/file/55839010951.pdfIn PDF document text
    • http://christopherspubandgrille.com/userfiles/files/ziseze.pdfIn PDF document text
    • https://samowar.me/userfiles/files/mesoxadijefatojoz.pdfIn PDF document text
    • http://huthamcauquanggiap.com/upload/files/vakaju.pdfIn PDF document text
    • http://elencostruzioni.it/userfiles/files/zovalaf.pdfIn PDF document text
    • http://hz-kontejnery.cz/ckfinder/userfiles/files/34164411342.pdfIn PDF document text
    • http://asustainable.com/global/file/vajopabutamazedus.pdfIn PDF document text
    • http://extrastyle.ee/ckfinder/userfiles/files/fajowegugoledozeweka.pdfIn PDF document text
    • https://bulgariapools.com/contents/files/53877508524.pdfIn PDF document text
    • http://trip-sale.ru/userfiles/file/tinekulexedazosuludak.pdfIn PDF document text
    • http://wjcopy.com/upload/files/zazumu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=android+dead+phone+data+recoveryPDF 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
stream_005_off000116b4.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x116B4 10560 bytes
SHA-256: 2181a1eba8ad9a020ad402ee3a3f9986a30cd2482d9b1c6ec06c8186e389b25e
font_00_sfnt_off0000d490.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD490 16300 bytes
SHA-256: 6a8af7bba1c5440a28cf8fd2a03155ea5f7a4a571025bd32aeb0b806d0f91fb5
font_01_sfnt_off0000fe9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE9D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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