Malicious PDF — malware analysis report

Static analysis result for SHA-256 51853c56921db9b2…

MALICIOUS

PDF

69.4 KB Created: 2021-09-11 12:52:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: a12ec828a6d57d574cee793a94de1279 SHA-1: aeefb5f5f458abdf4c563fc68f95c10aee9496f4 SHA-256: 51853c56921db9b27e5002a06dc043ab14619bc009edcf036a737bbffa247a4c
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution T1059.007 JavaScript

The file is identified as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, with one heuristic specifically flagging it as a link farm on disposable hosting. The PDF structure and embedded content suggest it is designed to redirect users to a network of sites, likely for malicious purposes such as phishing or malware distribution. No scripts were extracted, but the PDF structure itself is indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://asupuro.com/user_data/image/file/janeturezi.pdf In PDF document text
    • http://salwex.hu/file/bofuredukepogi.pdfIn PDF document text
    • http://precedent.by/_newsite/images_from_html_editor/file/77664470309.pdfIn PDF document text
    • http://bancasemecanino.com/userfiles/files/ravefufadipasikidi.pdfIn PDF document text
    • https://marciasmithconsulting.com/wp-content/plugins/super-forms/uploads/php/files/884f397eca147ddc07af7567fa1b3798/66584040945.pdfIn PDF document text
    • https://balarampurblock.in/ckfinder/userfiles/files/zejizirevamovodabadopaxo.pdfIn PDF document text
    • http://amongelite.com/ci/userfiles/files/gumoxi.pdfIn PDF document text
    • https://www.pelicanfinancialnetwork.com/ckfinder/userfiles/files/61079866237.pdfIn PDF document text
    • http://epoxidice.ro/mm/file/57436123159.pdfIn PDF document text
    • https://duel.pl/userfiles/file/vilakarenudo.pdfIn PDF document text
    • http://innersolutions-uk.com/file/34943203103.pdfIn PDF document text
    • http://bangladeshceramicsociety.com/uploads/editor/files/dibuledarumedemedotipe.pdfIn PDF document text
    • https://hzautomatisering.nl/userfiles/file/39666125039.pdfIn PDF document text
    • http://bindashnews.com/userfiles/file/34466056670.pdfIn PDF document text
    • http://hzosm.com/images/upload/File/ragudogelulunedilexokera.pdfIn PDF document text
    • http://beijingxinzhi.com/userfiles/file/20210906173834_1309934640.pdfIn PDF document text
    • http://planet-for-events.de/userfiles/file/4848057988.pdfIn PDF document text
    • https://ctcitsupport.com/media/files/zivuxun.pdfIn PDF document text
    • http://telecycling.info/files/file/61321485911.pdfIn PDF document text
    • http://handbook.hu/upload/page/file/60498152447.pdfIn PDF document text
    • https://capecoralliving.com/media/file/29949069878.pdfIn PDF document text
    • http://helenhotel.vn/upload/files/vexudepaligogutumapilaj.pdfIn PDF document text
    • https://hung168.tw/UserFiles/files/12822150066.pdfIn PDF document text
    • https://vegan-eshop.cz/data/file/zuwitizosexapilexizunok.pdfIn PDF document text
    • https://givemeit.ru/wp-content/plugins/super-forms/uploads/php/files/a9f13f3cf0686e337dde81a7d840ca77/93492658787.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=varieties+of+english+pdfPDF 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_off0000b35a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB35A 14404 bytes
SHA-256: abef8336451992cc46575586b36eb0f8d62346db4a399538129e14ec409a21e2
font_01_sfnt_off0000d75d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD75D 10744 bytes
SHA-256: 7054ee8c8fd74cf76b272fa2c0a603f4ea0940ae3b5a462a4922c364c5fee12d
font_02_sfnt_off0000efc7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFC7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1