Malicious PDF — malware analysis report

Static analysis result for SHA-256 91af3d50ad263337…

MALICIOUS

PDF

74.6 KB Created: 2021-10-08 06:56:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-07
MD5: a14aa8833517c6c0122f5306e5b1cd77 SHA-1: fc1af3f025eb87d3570cbf9aa79906076413e2c2 SHA-256: 91af3d50ad263337bba1b4e40d8c0526a454873452e8a8bbebfe8fb078c3028b
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains embedded JavaScript and numerous external URIs, many of which point to potentially malicious domains. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a link farm structure, suggesting the primary purpose is to redirect users to other sites. The embedded JavaScript likely facilitates this redirection or further malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 6

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://sadhankendra.org/erc/media/jezavajosuporug.pdf In PDF document text
    • https://cheesykeju.com/contents/files/26882383629.pdfIn PDF document text
    • https://dewalt-naradi.cz/media/upload/editor/file/xizonozidebejufezosadino.pdfIn PDF document text
    • http://artgrafika.cz/userfiles/file/63843393774.pdfIn PDF document text
    • http://hawaii-resort.info/images/blog/file/17527605489.pdfIn PDF document text
    • http://gonvvama.net/filespath/files/20210921004805.pdfIn PDF document text
    • https://tonicsuitemusic.com/userfiles/files/4413125313.pdfIn PDF document text
    • https://tutorsbureau.net/userfiles/file/3747645733.pdfIn PDF document text
    • http://czernavendeghaz.hu/admin1/file/34524062097.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1615ca8a662783---gawabujuseniz.pdfIn PDF document text
    • https://thailonghoang.vn/upload/files/58853854765.pdfIn PDF document text
    • http://www.sauminandy.com/fckimages/file/kulizerubikisaxukubaf.pdfIn PDF document text
    • https://ihotel2b.com/upfiles/editor/files/62476943338.pdfIn PDF document text
    • http://gld-lining.com/user_img/files/reburibaramaxojakodirupax.pdfIn PDF document text
    • https://signatureshreyas.in/userfiles/file/42248645517.pdfIn PDF document text
    • http://tipkeo.com/js/ckfinder/userfiles/files/97453565534.pdfIn PDF document text
    • http://leebyenghun.com/new/upload/board/files/juraverawetekafutuno.pdfIn PDF document text
    • https://sahodayabbsr.com/test/fckeditor/file/dosifurilog.pdfIn PDF document text
    • https://pointswestliving.com/ckfinder/userfiles/files/64340941470.pdfIn PDF document text
    • http://bestapp4u.com/admin/uploadedfiles/file/72747993497.pdfIn PDF document text
    • http://lideparts.com/userfiles/file/1631256468.pdfIn PDF document text
    • http://watthaistuttgart.de/userfiles/file/41660852975.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=what+does+a+giraffe+like+to+eatPDF 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_off0000bf54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF54 17572 bytes
SHA-256: d880ec20d2447648976648524893db14a52940fcc11e8a5f44855fecf47b30a9
font_01_sfnt_off0000ec40.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC40 10616 bytes
SHA-256: 287049c3cdf30f7f9c25cf95cf0bb2ebf4e7cc9df1f2d075ad74a3fd4bd23060
font_02_sfnt_off00010478.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10478 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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