Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4088b528dd6ad24…

MALICIOUS

PDF

67.6 KB Created: 2021-05-21 02:57:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 6e7e769adeb6b609dbcb677aea9ec3f3 SHA-1: 5b984a63145fa50f5f0d306d829bc67bbea06f9d SHA-256: c4088b528dd6ad2452f9aece04f029367b554d617790eec3dfd1c5dfca59bbf6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, contains references to 'cub cadet lt1045 deck springs' and 'wkhtmltopdf', indicating a potential lure for specific search terms. No scripts were extracted, but the PDF structure itself facilitates the redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • 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://medvor.ru/uplcv?utm_term=cub+cadet+lt1045+deck+springs PDF link annotation
    • https://aedwea.com/upload/foto/gitogipemufinenamijejusul.pdfIn PDF document text
    • http://ventilatoryzlin.cz/images/file/kefom.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608062c4169d8---suwifowipeme.pdfIn PDF document text
    • http://www.zopfitravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160850a98ba868---44841419720.pdfIn PDF document text
    • http://www.theflightfest.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ddbe9ddb4c---jonesizunebutal.pdfIn PDF document text
    • http://caacoding.net/wp-content/plugins/formcraft/file-upload/server/content/files/1609fd776ad3d2---wixenemeluzelop.pdfIn PDF document text
    • https://www.generalutilities.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073e838d105d---sizudafawejotiwufodafifin.pdfIn PDF document text
    • http://www.webtony.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608d4e1cdde49---gizeli.pdfIn PDF document text
    • http://www.next-conseil.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1608299b6a5e5f---49377183225.pdfIn PDF document text
    • https://simovi.mx/wp-content/plugins/formcraft/file-upload/server/content/files/16091185edbbac---37038036429.pdfIn PDF document text
    • https://daleplumbinginc.com/wp-content/plugins/super-forms/uploads/php/files/5deff27d19da22cb473ee8314cf07c70/fipaxewejaloxifaxikok.pdfIn PDF document text
    • http://kondicionery-ivanteevka.ru/upload_picture/file/bipobemitix.pdfIn PDF document text
    • https://tuabogadoangel.com/wp-content/plugins/super-forms/uploads/php/files/60a954a417ba81258d76d3086f47b744/29470124514.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cb77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB77 5756 bytes
SHA-256: 529e6584387182756133374bf3edfaeb23e04a8648858ecc6e6f72a4879fcab5
font_01_sfnt_off0000df19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF19 10104 bytes
SHA-256: 054e439013549f9551904076a9349c40d3e4ad93ce77b2a7683ea13c617a7359

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