Malicious PDF — malware analysis report

Static analysis result for SHA-256 5266734c233676f6…

MALICIOUS

PDF

77.8 KB Created: 2021-09-04 18:11:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: ad03d9e1f909cf9d67568ca0e1396cd1 SHA-1: 6f930b1e8c57a9646bba1a9086b85b5be8187c32 SHA-256: 5266734c233676f64378bb826cbd09edc651ddea5ce399a5cd67d2d4a0e77925
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it is a link farm on disposable hosting. The PDF contains numerous external URIs pointing to various domains, suggesting an attempt to redirect users to potentially malicious content. While no scripts were explicitly extracted, the PDF structure and heuristic firings strongly suggest it's designed to exploit users by directing them to external sites, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://inwebjor.ru/uplcv?utm_term=always+usually+sometimes+never+esl+worksheet PDF link annotation
    • http://clinicaveterinariacene.com/userfiles/files/62215479479.pdfIn PDF document text
    • http://www.mezmat.ru/ckfinder/userfiles/files/zagiwojarabakejigixekog.pdfIn PDF document text
    • http://staractivecollection.com/resimler/site/files/xonabolaguwomulapukawu.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610a5af00137f---84459777234.pdfIn PDF document text
    • https://jasz-pap.hu/UserFiles/file/4092333268.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/1612d85a3461ea---1562447175.pdfIn PDF document text
    • http://portalcom-b2b.es/img/user///file/_0312733001625606690.pdfIn PDF document text
    • http://zonazero.es/userfiles/file/33527443408.pdfIn PDF document text
    • http://harckocsik.hu/userfiles/file/47285444389.pdfIn PDF document text
    • http://a1climbing.com/userfiles/files/60749353104.pdfIn PDF document text
    • http://kolaykanal.com/userfiles/files/52358603890.pdfIn PDF document text
    • http://myshopekerala.com/userfiles/file/wajamigifutoxoxusubisix.pdfIn PDF document text
    • https://guruamardaspublicschool.com/userfiles/files/bemogowo.pdfIn PDF document text
    • https://regiefranchet.fr/userfiles/files/19071060308.pdfIn PDF document text
    • http://harlit.com/upfiles/file/samubakugokebapepaf.pdfIn PDF document text
    • http://bscartridge.com/pic/10952593795.pdfIn PDF document text
    • https://boucherienabli.com/uploads/FCK_files/file/14034160151.pdfIn PDF document text
    • 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_off0000cb7b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB7B 17712 bytes
SHA-256: 773ad793803e424c9b414fe6f8d22feed3d38ce9989bb50f63cd45d3b98566a7
font_01_sfnt_off0000f96a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF96A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011181.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11181 10812 bytes
SHA-256: 87d8122dbf6fab6b4684374deccf732904261922142e6e2aff11d51ffb3834e3

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