Malicious PDF — malware analysis report

Static analysis result for SHA-256 20b71485cf0374bf…

MALICIOUS

PDF

73.0 KB Created: 2021-05-10 14:20:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: cbcd4e2dfa6b5fae117267a7362187fc SHA-1: d5cedbf385896b67a5a627827447bf117a809086 SHA-256: 20b71485cf0374bfdb0817feac8ce7f150b8e194a27e1233f8cc00f7bffb0e7e
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous embedded URLs pointing to compromised websites, suggesting it's part of a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, contains references to 'all english opposite words pdf' and was generated by wkhtmltopdf, a tool often abused for creating malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://stkvn.ru/wp-content/plugins/super-forms/uploads/php/files/06fd31837e31c6ec58c65bdd6b3c4604/jolafa.pdf In PDF document text
    • http://clinicacomciencia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607ff41f5771a---2913969822.pdfIn PDF document text
    • http://gennarimaq.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608857ec105d6---65915482726.pdfIn PDF document text
    • https://astoriareiki.com/wp-content/plugins/super-forms/uploads/php/files/1e0ae99c9956d4a992f090b4ff5fdd60/30917980858.pdfIn PDF document text
    • https://yourlightingbrand.com/wp-content/plugins/super-forms/uploads/php/files/bd10cdd112ba8f47ab1740d00d6578b6/sidifikakinujezofevov.pdfIn PDF document text
    • https://canadianrelocation.net/wp-content/plugins/formcraft/file-upload/server/content/files/1606e8a3be52f0---sagubowabe.pdfIn PDF document text
    • https://amerismithenterprises.com/wp-content/plugins/super-forms/uploads/php/files/adcd3ff97ba80d1fc60cedfa3ee16551/ruvotuvugureninovem.pdfIn PDF document text
    • https://donnasalon.ru/wp-content/plugins/super-forms/uploads/php/files/1ad01a79a521ae116532434661ede15a/xijuwagesawel.pdfIn PDF document text
    • https://centrobrands.com/wp-content/plugins/super-forms/uploads/php/files/d90e9910e05a158c321a03f99e1bc0a9/bufigebetazifoxo.pdfIn PDF document text
    • https://www.businesswatchguardingservices.co.uk/wp-content/plugins/super-forms/uploads/php/files/vhhdo7m70pg8mn8p90d8jkr4fi/lejedosa.pdfIn PDF document text
    • http://bawaconstructions.com/editorData/file/28223164450.pdfIn PDF document text
    • https://www.urban-quartz.co.uk/wp-content/plugins/super-forms/uploads/php/files/ccd93d9218da9a6c0069b802cfb28333/gomimoti.pdfIn PDF document text
    • http://villaturri.it/wp-content/plugins/formcraft/file-upload/server/content/files/16086f566a25af---78572021661.pdfIn PDF document text
    • http://vasilii-orlov.fun/wp-content/plugins/super-forms/uploads/php/files/a64602519955fcd87ff1caa2496d8d78/48343622908.pdfIn PDF document text
    • https://gbeequestriansurfaces.com/wp-content/plugins/super-forms/uploads/php/files/ca49ef54ctckce5ujjknaedv2r/9813492522.pdfIn PDF document text
    • https://mymango.ru/wp-content/plugins/super-forms/uploads/php/files/c57a2b273495d19816ea21af3c1b3e7b/47866264575.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/h793kun4fc7ektjdisfesduu3f/99250177534.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/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=all+english+opposite+words+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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e02f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE02F 5172 bytes
SHA-256: 0840b0757825bc8258ff7632f82a98484628ac8aad1432264fce45726f094ce9
font_01_sfnt_off0000f1de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1DE 11032 bytes
SHA-256: db7911ed0d302738c304deede07030258bac13b24310e68cb552c455ac2e75a2

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