Malicious PDF — malware analysis report

Static analysis result for SHA-256 b23cd7a37a77b2e3…

MALICIOUS

PDF

75.0 KB Created: 2021-06-19 08:11:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-26
MD5: d73261cf9e9f44be3adfa34fa3c5b254 SHA-1: b63f968f07a9b96faaee07872bb0f06152813b34 SHA-256: b23cd7a37a77b2e337175ff0f6de50813696c38f84f283a22f193af68625ae05
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1190 Exploit Public-Facing Application

The PDF contains a link farm pointing to multiple compromised WordPress sites, specifically targeting their file upload plugins. These links host other PDFs, suggesting a multi-stage attack. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or malware distribution.

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://oneremote.ru/wp-content/plugins/super-forms/uploads/php/files/b0789d4a917d4c465263037775a7dd26/72815516469.pdf In PDF document text
    • https://www.mercedesbenzofaustinservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c13dc42a64f---57379194424.pdfIn PDF document text
    • http://kfbi.ru/content/file/79188784315.pdfIn PDF document text
    • https://burstallconrad.com/editor_files/file/mevebu.pdfIn PDF document text
    • https://hightechrustremovers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607e895913ba7---rosuvebuxekifewupakagaxi.pdfIn PDF document text
    • https://www.pfgpartners.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1606c7fdf94ce1---36173254123.pdfIn PDF document text
    • http://stressmanagement-karriere.de/userfiles/file/vokoroded.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/160affd3ce58ad---44191684507.pdfIn PDF document text
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/on8eiid9kig4778s62d259db41/68649442797.pdfIn PDF document text
    • https://esteticarcare.com/wp-content/plugins/super-forms/uploads/php/files/c7d5bfcb7c8742f2feb4df87d9869083/95471627317.pdfIn PDF document text
    • https://travelselection.us/wp-content/plugins/formcraft/file-upload/server/content/files/16096bab52cb35---fekizefitidik.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074c5e42072b---wobizabokinodox.pdfIn PDF document text
    • https://akemi.ro/hirek/file/telosetitukude.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
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=the+spiritual+exercises+pdfPDF link annotation
    • 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_off0000dcf9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCF9 4924 bytes
SHA-256: b17ea75c3ba6411a72816990b4f660956b7930d744861437edf1ba620ec6ccd0
font_01_sfnt_off0000edd1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDD1 10412 bytes
SHA-256: 2e14ad902b212eb4d2107dec74a7a866acf0b0b4a43a1bbf7f65cf37d2fa2db2
font_02_sfnt_off00011160.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11160 4324 bytes
SHA-256: 1062cd8ddf90f4344fa193b395386d5669df1a952e5759311ca261a71931f361

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