Malicious PDF — malware analysis report

Static analysis result for SHA-256 3cb8b82b7c23837e…

MALICIOUS

PDF

78.2 KB Created: 2021-06-20 18:47:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 5cd6f8366a3f2819054cd6575dd870b4 SHA-1: 62ab6876eda0087e8d7dde5013918c5ad56065e3 SHA-256: 3cb8b82b7c23837e059dff6c23d36b8cad16bca8fe1e3dcf3fc4fc33b3d21e98
156 Risk Score

Malware Insights

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

This PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links to external websites, many hosted on compromised WordPress installations or disposable domains, suggesting a link farm or phishing lure. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, but the presence of embedded URLs and the heuristic firings strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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 http://aimic.com/userfiles/file/79526123482.pdf In PDF document text
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160763e6e2da56---13217499735.pdfIn PDF document text
    • https://www.etbsupplies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f3fd9d2478---savarazibu.pdfIn PDF document text
    • https://adm.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/30e73a02287ef909358de3465ade073d/gosijobuzisafibagewekuvi.pdfIn PDF document text
    • https://areicon.com/images/file/lerepopan.pdfIn PDF document text
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/56f0e03f01e7d234b132d5582609399f/bafoxodilugixowofokat.pdfIn PDF document text
    • https://hmjrgoldhockey.org/wp-content/plugins/super-forms/uploads/php/files/8a6403e646905f280d04f4c0f189f1ec/37745412411.pdfIn PDF document text
    • https://hopefor.today/wp-content/plugins/super-forms/uploads/php/files/674756a8ced197b7be8f25686d6002e4/duguwapa.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f21d2cad14---1440559651.pdfIn PDF document text
    • https://regeneracion-capilar.com/wp-content/plugins/super-forms/uploads/php/files/ca5d5b87f156e1143beb28af9157c113/gixuvegupanamevikitelam.pdfIn PDF document text
    • https://tehnol.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1606d5568767da---wubibirumokejarem.pdfIn PDF document text
    • https://maxim-catering.de/wp-content/plugins/super-forms/uploads/php/files/f6fb896637838htp42aj65kc0j/68475002547.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f5e5a282eb---64437441489.pdfIn PDF document text
    • http://uleshuzatshop.hu/files/file/raxisojuto.pdfIn PDF document text
    • https://salvatoredivilio.it/userfiles/file/nixufajosozasijudex.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=how+many+calories+do+you+burn+in+one+jumping+jackPDF 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f2e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2E8 5828 bytes
SHA-256: 811088460f71419d2705eda243cbc1b7d0044d5631daef5074c446265ed6a94a
font_01_sfnt_off000106b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106B9 11252 bytes
SHA-256: d29891cd050ffcf1432dcc3f43fdfdd48f27a221c8f19b08c0bbfc115deac06e