Malicious PDF — malware analysis report

Static analysis result for SHA-256 5283b64c5b0d5857…

MALICIOUS

PDF

79.5 KB Created: 2021-06-14 21:50:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: b827182f99f395af8f55e7a6b8e7df92 SHA-1: 8337aca908cf5850adc8dd5d2753b53aa0f9d90c SHA-256: 5283b64c5b0d5857c98dfc5f066d40fd8f267b5e42dc1e37352d512cfcb60b52
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier indicating a high probability of maliciousness. It functions as a link farm, directing users to numerous external websites, many of which appear to be hosted on compromised WordPress installations. The presence of 'utm_term' parameters suggests an attempt to track user engagement, common in phishing or malware distribution campaigns.

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://medvor.ru/uplcv?utm_term=discord+server+text+channel+ideas PDF link annotation
    • https://hmv.ir/wp-content/plugins/formcraft/file-upload/server/content/files/160b85ef2db136---sunuxe.pdfIn PDF document text
    • http://www.publicitymailing.ie/wp-content/plugins/formcraft/file-upload/server/content/files/160727ea7ae482---69176381589.pdfIn PDF document text
    • http://loaamtran.vn/files/usersfiles/files/wirubu.pdfIn PDF document text
    • http://veronicanealhome.com/wp-content/plugins/formcraft/file-upload/server/content/files/2/16089a59881f18---wapagoxazefojenet.pdfIn PDF document text
    • http://rustproofingottawa.com/userfiles/file/nejakazegofipus.pdfIn PDF document text
    • http://xahscw.com/userfiles/file/2952026449.pdfIn PDF document text
    • https://sellerflows.com/wp-content/plugins/super-forms/uploads/php/files/110c44e34666cba4d4d0f2c615a2e220/fowuxezovazenovomu.pdfIn PDF document text
    • http://bertrandetgastineaudesigners.com/userfiles/file/13214730980.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086fc9743592---wonaw.pdfIn PDF document text
    • https://www.andyselfstorage.co.uk/wp-content/plugins/super-forms/uploads/php/files/mojbrg6rh3haotpql7f1el0afe/23039012149.pdfIn PDF document text
    • https://sharidendesignasphalt.com/wp-content/plugins/super-forms/uploads/php/files/815ee69abb1bac6b7e0ac84f2ae34014/gazaralezogunugofu.pdfIn PDF document text
    • http://www.k-24.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b431fa12873---xozobik.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_off0000fa0f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA0F 5152 bytes
SHA-256: 5e0c871a6dd005e9151b4fb5c302c375bbc747b056a314d6ec79a0b58a574250
font_01_sfnt_off00010b9c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B9C 10736 bytes
SHA-256: 9781e7ae372e11fff0326032e25656cfb29bc952c418512f77c30fe929ac7f5a

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