Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4c1596d77644107…

MALICIOUS

PDF

77.2 KB Created: 2021-09-03 22:05:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 8397f2bbeaa4973e66e3ae1ff497fcd6 SHA-1: 8f26b2e25a162a50572cf8ffe54f4393fd5c633e SHA-256: c4c1596d776441073c88a8b4a3d328f39df5419a356139bb112ab6f16352ae70
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to various domains, many of which appear to be disposable or compromised hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports that the document's primary purpose is to act as a link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://smidgel.ru/uplcv?utm_term=market+leader+pdf+intermediate PDF link annotation
    • http://esrafisek.com/images_upload/files/23750147239.pdfIn PDF document text
    • http://backupcenters.com/userfiles/file/24007892757.pdfIn PDF document text
    • https://xigmatek.com/upload/files/32314852645.pdfIn PDF document text
    • https://na-nule.ru/wp-content/plugins/super-forms/uploads/php/files/o93invcf8h5s51lrvvnplu5se2/volisalimipiluwewi.pdfIn PDF document text
    • http://geniuschulatutor.com/userfiles/files/natewatodamuxirupek.pdfIn PDF document text
    • http://etenindex.nl/images/uploads/jubami.pdfIn PDF document text
    • https://optical-axis.com/uploads/files/202108302144441945.pdfIn PDF document text
    • https://postelezmasivu-olomouc.cz/ckfinder/userfiles/files/18870727977.pdfIn PDF document text
    • https://autoteam.in/ckfinder/userfiles/files/32425064191.pdfIn PDF document text
    • https://patriot.ch/wp-content/plugins/super-forms/uploads/php/files/nvph2h6j38lmstibqtltam72nd/bitawopuzapefarek.pdfIn PDF document text
    • http://rudolphalexander.com/uploads/files/vigivetag.pdfIn PDF document text
    • http://bighost.vn/uploads/userfiles/file/37943154638.pdfIn PDF document text
    • https://sharidendesignasphalt.com/wp-content/plugins/super-forms/uploads/php/files/946a7fe3ffc9ad9b62e07bc07c2c5660/wavadesotigunepugun.pdfIn PDF document text
    • https://bamfieldrental.com/userfiles/file/rapurodapixuwidosobu.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/67ee7f65e5cdff01a9da13bedefdca86/rewikufakotozavupili.pdfIn PDF document text
    • https://www.brunosistemi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f386fd88fb5---87798559922.pdfIn PDF document text
    • http://fst-uinsu.net/userfiles/files/lobugifefozogawexolege.pdfIn PDF document text
    • https://agrimal.pl/userfiles/file/xufowize.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1609db5533320f---sisinuragonuvewagaguke.pdfIn PDF document text
    • http://flygarfield.net/userfiles/file/fiwujobinuwejumadosuwelo.pdfIn PDF document text
    • https://flyfinz.com/userfiles/files/91729345092.pdfIn PDF document text
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/16097741a93bda---94168183888.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_off0000c8c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8C0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e0d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0D7 10456 bytes
SHA-256: 4815648437489af8be14890e36268f0bf0f302044ee54e516a708be081ba298d
font_02_sfnt_off0000f87a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF87A 18032 bytes
SHA-256: 514ef340bbae3501f719b5fe85fd1510e938b03bbec00da163338a5e82c54ea5

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