Malicious PDF — malware analysis report

Static analysis result for SHA-256 311a9eaebec28175…

MALICIOUS

PDF

75.4 KB Created: 2021-09-24 03:01:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 038cc4b8756d4e23bc155b1cfa336cdc SHA-1: 95b7f7a628a7f58b955f7e79957ad902dec8cd23 SHA-256: 311a9eaebec2817516e3da338039b207d6364d2cb70c3e3bad7c80847311a242
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including ClamAV and an ML classifier, indicating malicious intent. It contains numerous external links, many pointing to potentially compromised or disposable hosting, suggesting a link farm designed to redirect users. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this. While no scripts were explicitly extracted, the nature of the links and the PDF structure suggest it's likely part of a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9934

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://kuni.ro/app/webroot/files/userfiles/files/68266992977.pdf In PDF document text
    • http://wpchkg.com/upload/image/file/89701603623.pdfIn PDF document text
    • http://crystaltrade.hu/data/file/rasajazizutogebox.pdfIn PDF document text
    • https://padservhosting.com/userfiles/file/ripatuka.pdfIn PDF document text
    • http://studiofantino.it/userfiles/files/53434570626.pdfIn PDF document text
    • https://institut-arabe.org/ckfinder/userfiles/files/dirujude.pdfIn PDF document text
    • https://faceless.me/userfiles/files/10247990667.pdfIn PDF document text
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/1613879af61703---49570347154.pdfIn PDF document text
    • http://daoltrading.com/userData/board/file/kuvirefozenebujonasapu.pdfIn PDF document text
    • http://odnoklassniki-files.ru/images/uploads/files/rizabazobelenososakojo.pdfIn PDF document text
    • http://oio.cn/uploadfiles/files/29738909444.pdfIn PDF document text
    • http://vattucongtrinh.com/userfiles/file/15454918522.pdfIn PDF document text
    • https://tekstilkentrehber.com/upload/ckfinder/files/79059835453.pdfIn PDF document text
    • http://combatkuntao.com/ckeditor/ckfinder/userfiles/files/kexusatubizadazotijobukal.pdfIn PDF document text
    • http://woodwork.pl/ubezpiecz/obrazy/file/jijagumesaj.pdfIn PDF document text
    • https://villamishkan.com/310renonew/front/images/files/kizokakowizal.pdfIn PDF document text
    • https://www.pfgpartners.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1614b964c13beb---xidomariponusibagunimotu.pdfIn PDF document text
    • https://www.oasipizza.it/wp-content/plugins/formcraft/file-upload/server/content/files/16143aa717e3fe---nunabi.pdfIn PDF document text
    • https://myvideoclasses.com/ci/userfiles/files/kijalepesexilozexazora.pdfIn PDF document text
    • http://viviapalermo.com/userfiles/files/97125379336.pdfIn PDF document text
    • http://brianhaymore.com/images/e/file/12150330598.pdfIn PDF document text
    • https://illustrations.noche.fr/images/files/32121771973.pdfIn PDF document text
    • http://windcampus.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142101f23dce---torilusixeropepunaxeb.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135328c4d754---7785451734.pdfIn PDF document text
    • http://vinhosnorte.com/images/files/28478384680.pdfIn PDF document text
    • http://kalmi.ru/upfiles/files/sojafekobagavikutidiwe.pdfIn PDF document text
    • http://fantalife.nl/userfiles/file/37228062417.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=what+happens+when+i+factory+reset+my+phonePDF 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_off0000c1cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC1CB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d9dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9DD 17280 bytes
SHA-256: b3f329255a57a2bd67b9656f5e7df7ef6826cf8c46588d6d11529051214dfffe
font_02_sfnt_off00010621.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10621 10892 bytes
SHA-256: 09410e00183991da0a8329bca048051d45968085afa9e082534fe12ae46156ae