Malicious PDF — malware analysis report

Static analysis result for SHA-256 adf9ac10924e89e1…

MALICIOUS

PDF

89.4 KB Created: 2021-09-05 17:48:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 3bfc4706102a9c6dce244a8c9481b7fa SHA-1: 760e3e60f5ec3f4a77a6e94cc2202a2310d7b1f8 SHA-256: adf9ac10924e89e1c609c8886d754db968a366bf3a629840ff8b89e4cffe2092
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, hosting numerous links to other PDF files on compromised WordPress sites and disposable hosting. The primary URL, 'https://krisoc.ru/uplcv?utm_term=neoplasia+maligna+de+prostata+pdf', suggests a potential phishing lure related to medical information. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but containing embedded URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9979

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://krisoc.ru/uplcv?utm_term=neoplasia+maligna+de+prostata+pdf PDF link annotation
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160bc27f0bd47d---wafufo.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b62deb04605---pavub.pdfIn PDF document text
    • https://cvconstructionsgoa.com/pharma/admin/userfiles/file/87120731726.pdfIn PDF document text
    • https://ewms.vn/wp-content/plugins/super-forms/uploads/php/files/f24bumbkca26bqk502mqt46u2g/vifejifuxipijox.pdfIn PDF document text
    • https://pinotcar.com/wp-content/plugins/super-forms/uploads/php/files/941cbe9239cc83df3af8582ff25f86df/859147420.pdfIn PDF document text
    • https://www.syah.org/wp-content/plugins/super-forms/uploads/php/files/87e62fbe10c4e1b13c5f64cbfb557790/vajuta.pdfIn PDF document text
    • https://perleyparish.org/wp-content/plugins/super-forms/uploads/php/files/a5888567f63412314ebf8c38f13ea2fc/makugesevexitujubasefe.pdfIn PDF document text
    • http://shahnawazonline.com/uploads/files/dumamu.pdfIn PDF document text
    • http://ibtaker.ps/userfiles/file/29564765509.pdfIn PDF document text
    • https://samsungdvm.net/upload/ckfinder/files/pakinegamub.pdfIn PDF document text
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608fb859d3829---fuwepa.pdfIn PDF document text
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/6ad804583fdc6aee5bfac7e3c9b35094/55283829590.pdfIn PDF document text
    • https://frontiersneurophotonics.org/wp-content/plugins/formcraft/file-upload/server/content/files/1/160b51c1f133b9---bizufu.pdfIn PDF document text
    • http://www.191seo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d3d6338aa6---nofawodipuwetimikigomof.pdfIn PDF document text
    • https://apoc.com.au/wp-content/plugins/super-forms/uploads/php/files/33e63f9f7915ce7a2a297566f62b72a2/rudaraxuriniliritivivu.pdfIn PDF document text
    • https://rybczewice.pl/userfiles/file/25422862051.pdfIn PDF document text
    • https://coaching-jk-academic.com/ckfinder/userfiles/files/13896497033.pdfIn PDF document text
    • https://pikewallis.no/wp-content/plugins/formcraft/file-upload/server/content/files/160b5517f0308d---rafonuvapeve.pdfIn PDF document text
    • http://firmen-bekleidung.at/userfiles/file/zulozulevuxugivejelivuv.pdfIn PDF document text
    • http://www.annaleehuber.com/content_files/file/68662222266.pdfIn PDF document text
    • http://ip-golubev.ru/ckfinder/userfiles/files/84797268030.pdfIn PDF document text
    • https://okud-istra.hr/userfiles/file/18872708450.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_off0000f682.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF682 18992 bytes
SHA-256: b8bcce7c10475f9f00a69d1447bc077c6c29e4cd5e349f78157ab59d9bda6417
font_01_sfnt_off00012750.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12750 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013f67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F67 10816 bytes
SHA-256: 51c2673df4d6cc1baa276788d601c062fde90c9eed039162252493e0e77d64d7

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