Malicious PDF — malware analysis report

Static analysis result for SHA-256 05b1b8c838aba257…

MALICIOUS

PDF

72.1 KB Created: 2021-06-21 15:48:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: 1bbbbf9abf9c0b3a62fc91696c20f957 SHA-1: 759199c98699c0e8041aa869d84117cc408b0d28 SHA-256: 05b1b8c838aba2578969c88c6d884dd4c918314ffc88b0e482e266fc156f40ec
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to compromised WordPress sites, suggesting it's part of a link farm designed to redirect users to malicious content. The presence of multiple distinct hosts and the use of 'utm_term' parameters indicate an effort to obscure the ultimate destination and potentially improve search engine ranking for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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=kids+english+story+book+pdf PDF link annotation
    • https://perleyparish.org/wp-content/plugins/super-forms/uploads/php/files/3fd8e8c450d820a3065860ba4f24cce7/81992669910.pdfIn PDF document text
    • http://crystalnymph.by/wp-content/plugins/super-forms/uploads/php/files/87e288e98d94d94c98b731a8fbe9b681/lokasizal.pdfIn PDF document text
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/0aee82b2628f62b482073ebcf1725956/vikedatofura.pdfIn PDF document text
    • https://lokmangal.co.in/wp-content/plugins/super-forms/uploads/php/files/189d8d36aea2c560b5c3130a9e65510f/75974898962.pdfIn PDF document text
    • https://auf.vn/wp-content/plugins/super-forms/uploads/php/files/mugm8hun76jenjjiepfjkqql82/pabadobapep.pdfIn PDF document text
    • http://sllight.ru/design/img/upload/file/jazanegufumiwezabel.pdfIn PDF document text
    • https://www.geosuiteonline.de/wp-content/plugins/formcraft/file-upload/server/content/files/16070100e3574d---23168271506.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609d8fbe9ed6e---dugukafojibiromux.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/7fvqvklnis9s2i4lpgo8lrmdmq/37710456953.pdfIn PDF document text
    • http://fashioncenterpoint.com/wp-content/plugins/super-forms/uploads/php/files/b88d50dc3fd545b7cfb8b46ad8731eaf/93988774492.pdfIn PDF document text
    • http://zawayakw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c6b50f3256---vewevixulegamokone.pdfIn PDF document text
    • https://total-sport.pl/img/upload/files/10760866752.pdfIn PDF document text
    • https://transcendenceit.com/wp-content/plugins/super-forms/uploads/php/files/582257293a7bf98d4d7b06505c1371df/51281952273.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_off0000db8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB8D 5368 bytes
SHA-256: 6c74da296644107fa1605608ad96fb81c108721cd8593510643bd564f2bff6bb
font_01_sfnt_off0000edce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDCE 10812 bytes
SHA-256: f923637c82d414e3d8269d89f81abd8caf7b98bac4d9fbb693e2f4bf2cab97c3

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