Malicious PDF — malware analysis report

Static analysis result for SHA-256 d81b93f4b4091ea5…

MALICIOUS

PDF

82.3 KB Created: 2021-06-14 21:11:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: d7364d6781a5858993049c8fcc117cb4 SHA-1: 378666d1f6f9ca7e14efa2f05a73dca2582bdbf2 SHA-256: d81b93f4b4091ea5cddb02cbcdd1f6308a9078580646d4eedc9902ce8ba8ae1d
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The document contains numerous embedded URLs pointing to compromised WordPress sites and other domains, suggesting it functions as a link farm for phishing or malware distribution. The presence of PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports this attack pattern.

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://synerhu.ru/uplcv?utm_term=summary+the+catcher+in+the+rye PDF link annotation
    • http://getawaynewzealand.co.nz/wp-content/plugins/formcraft/file-upload/server/content/files/160bb86a91e1a5---84357768882.pdfIn PDF document text
    • http://payassistinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/160824d67e1ea3---32792823799.pdfIn PDF document text
    • https://www.accidentinjuryalbuquerque.com/wp-content/plugins/super-forms/uploads/php/files/q1gdfk9v7nc7s3rlgqluqvk60m/gunar.pdfIn PDF document text
    • https://apoiotelecom.com/imagens/img_fckeditor/file/74448050894.pdfIn PDF document text
    • https://sakitonus.ru/wp-content/plugins/super-forms/uploads/php/files/ddb7e71a08619d90db2059c3082a791b/kosuripeditajuwalorerej.pdfIn PDF document text
    • https://www.harnoordesigns.com/wp-content/plugins/super-forms/uploads/php/files/bdkfr9dlcn2fkf411q6j7mamj1/34141198504.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607042f571188---jofamasonapewulosemojuxo.pdfIn PDF document text
    • http://adveotec.com/img/file/16460663264.pdfIn PDF document text
    • http://www.britocunhaadvocacia.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/1609d66ca5a111---12147946079.pdfIn PDF document text
    • http://splogservice.ru/content/file/mitumadosoxo.pdfIn PDF document text
    • https://kantankacreative.com/wp-content/plugins/super-forms/uploads/php/files/a92a0c5be955be19af358500f385737f/53628571676.pdfIn PDF document text
    • https://joefairless.com/wp-content/plugins/super-forms/uploads/php/files/2dff5063fa863239fa2787e422cedd5d/bosoximezovadijebobagutu.pdfIn PDF document text
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/d77dcb0de36e219d232125dabb4778b5/89001794710.pdfIn PDF document text
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608b1b4725a72---45452235872.pdfIn PDF document text
    • https://www.adilaltinsoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080b17ae9c31---42922364433.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_off0001059c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1059C 5036 bytes
SHA-256: defb4e761f5e2d2881ee94753bd0a8eca3b31c903518aa23dfc8d449dba99542
font_01_sfnt_off00011696.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11696 11120 bytes
SHA-256: d8fe4b4613388b9607c39d20faea205e3cfaff87ba11cdfd7a99b15123413d98