Malicious PDF — malware analysis report

Static analysis result for SHA-256 4ec03b357f0fcda0…

MALICIOUS

PDF

84.2 KB Created: 2021-06-14 23:09:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-27
MD5: 0934e77c78d95bc68f1740e09f003bb3 SHA-1: 8224aa2117155696949586720b7966cdfcc2a5b0 SHA-256: 4ec03b357f0fcda08b0903baab31473c225cbcc4f5379583e27f78930353d5b6
156 Risk Score

Malware Insights

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

The PDF file is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm pointing to potentially compromised websites. The embedded URLs, such as 'https://smidgel.ru/uplcv?utm_term=design+research+methodology+pdf', are designed to mislead users into believing they are accessing legitimate content, while actually directing them to malicious hosts. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create PDFs from web content, further supporting the lure-based attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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=design+research+methodology+pdf PDF link annotation
    • http://americanpetrochemicals.com/customers/CMS-IMAGES/file/30499805249.pdfIn PDF document text
    • http://chalappuram.com/userfiles/file/1746966067.pdfIn PDF document text
    • https://jetaime-shop.com/files/nedala.pdfIn PDF document text
    • http://nutronicltd.com/userfiles/file/xinupusoniziwukebofani.pdfIn PDF document text
    • https://aedwea.com/upload/foto/nunorejoviwisubi.pdfIn PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608f9796b1c62---xaxipebisasejaxujemab.pdfIn PDF document text
    • http://jyjwqj.com/uploadfile/file/%5C/2021061005020399.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a2d4f3cb32---78410311137.pdfIn PDF document text
    • https://www.asahinafunnels.com/wp-content/plugins/super-forms/uploads/php/files/vm1g65vcd7b11lgket7serj200/jinegiw.pdfIn PDF document text
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/160711f2235bbc---pedizobode.pdfIn PDF document text
    • http://www.photobreak.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607ecf86382c0---97332706783.pdfIn PDF document text
    • https://www.schroedersales.com/wp-content/plugins/super-forms/uploads/php/files/b83e0cbaed60b391f59c075ac1421d6c/2151572031.pdfIn PDF document text
    • http://kawoka.com/userfiles/file/38895809644.pdfIn PDF document text
    • https://purpleleafestatebuyers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c2c076e405---pewulibematupomosemisavu.pdfIn PDF document text
    • https://pet-fashion.ro/mm/file/45794362046.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fe3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE3B 5460 bytes
SHA-256: 6e6aff36a325c18c0a7d4cb073dcea874603ccc20e1c4f8d614f2a7c0b4e67db
font_01_sfnt_off000110a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110A1 11468 bytes
SHA-256: c59a0ebb1e42eccd125ff87fc84630f28fa5e99c39d4231f8dded16c1de8a293
font_02_sfnt_off00013572.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13572 4324 bytes
SHA-256: ce7e2e230a41ba6fc2d7d2240890c8289d67876d84a3d076d67c0b48111c8230