Malicious PDF — malware analysis report

Static analysis result for SHA-256 99df51a93a849f92…

MALICIOUS

PDF

83.2 KB Created: 2021-10-04 12:32:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 6e9938bec85df12fb704b43614ce42e5 SHA-1: 83dfba4be87b2e0e755b4188f07ccd72d80f2df6 SHA-256: 99df51a93a849f92f1c2b63c31dd0866f51e4574a0dff6b8749dc932176fafa4
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to PDF files hosted on various domains, suggesting a link farm or redirection strategy. The 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic confirms this, indicating the PDF is designed to distribute links across many disposable hosts. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9833

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://abworder.com/uploads/files/43113671811.pdf In PDF document text
    • http://chocoenglish.com/_UploadFile/Images/file/kewapivub.pdfIn PDF document text
    • http://artetendasud.it/userfiles/files/88335700617.pdfIn PDF document text
    • http://hiredriver.com/uploads/assets/files/buwupex.pdfIn PDF document text
    • https://happyjourney.webtrails.in/ckfinder/userfiles/files/gogixudivukupijed.pdfIn PDF document text
    • http://furnitura-syndicat.ru/ckeditor/ckfinder/core/connector/php/uploads/files/29791975584.pdfIn PDF document text
    • https://cnc-ar.ro/files/file/vefumojevuturumevude.pdfIn PDF document text
    • http://autolubitel-irk.ru/userfiles/file/89699196189.pdfIn PDF document text
    • https://xn--fiqa735be48e.com/upload/files/tojifutubeluwe.pdfIn PDF document text
    • http://antik-cafe-bergen.de/wp-content/plugins/formcraft/file-upload/server/content/files/16141133e99cf2---texobu.pdfIn PDF document text
    • http://vncanada.vn/uploads/files/12493261464.pdfIn PDF document text
    • http://brlairport.com/images/file/tomarol.pdfIn PDF document text
    • https://schmitz.cz/res/file/siluguziwewukigagekezer.pdfIn PDF document text
    • https://christembassybarking.org/wp-content/plugins/super-forms/uploads/php/files/cec098e578f3acae24d0082319662213/gudekuridanijenezodino.pdfIn PDF document text
    • http://eviljoy.com/UserFiles/File/mamidekonoxipejulen.pdfIn PDF document text
    • http://nhuaduongnhapkhauaz.org/upload/files/gerabofezoja.pdfIn PDF document text
    • https://hockeymro.ca/docs/file/63484378297.pdfIn PDF document text
    • http://itagqatar.com/itag/file/files/65664041030.pdfIn PDF document text
    • http://st03.it/userfiles/files/budolabeduva.pdfIn PDF document text
    • http://support-cmu.com/filedata/file/wovedilonod.pdfIn PDF document text
    • http://xn--80aafkqcanfpgnhbng3b5i9a.xn--p1ai/pict/file/17077356007.pdfIn PDF document text
    • http://pnktools-th.org/ckfinder/userfiles/files/77422727937.pdfIn PDF document text
    • https://artgallery.devctn.com/ckfinder/userfiles/files/34056822161.pdfIn PDF document text
    • https://fptica.ru/images/file/48997860520.pdfIn PDF document text
    • https://tsolisp.com/files/file/82609400872.pdfIn PDF document text
    • http://baigeleather.com/userfiles/file/25691527691.pdfIn PDF document text
    • http://soft-pro.hr/upload/datoteke/tiviwej.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=freezing+rows+in+excelPDF 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000decc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDECC 10368 bytes
SHA-256: d6725d3a5e305b449d664a932dbe03a9f2a942597013c90c746c4a8c0aa29e20
font_01_sfnt_off0000f66d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF66D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010e7f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E7F 18832 bytes
SHA-256: dea5af920e7aa6abbc8efd210e5d92812122bd5ec61bbc6165b1c6960a620fd7