Malicious PDF — malware analysis report

Static analysis result for SHA-256 851939bfd4ab63a8…

MALICIOUS

PDF

81.8 KB Created: 2021-09-18 00:58:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 0506c1daee3822a8abb09fa307692edb SHA-1: 5f939f1d4b37f6b6f900ddb07275855160445584 SHA-256: 851939bfd4ab63a8a541e7efe9da7a8e190b9e48ef75e050a837b80ce6aa5f72
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ML and ClamAV as malicious, with heuristics indicating it functions as a link farm on disposable hosting. The document body is heavily obfuscated, but the presence of numerous external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly suggest a phishing or malware distribution attempt. The primary attack pattern involves directing users to a network of potentially malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://efficientinfocomm.com/ckfinder/userfiles/files/penataxupopoxibujelebuk.pdf In PDF document text
    • http://bebaldebaran.eu/userfiles/files/dazazudigupotolagezedo.pdfIn PDF document text
    • http://reanda.com/jingkelun/userfiles/files/20210908035747.pdfIn PDF document text
    • http://nail-free.com/ckfinder/userfiles/files/78517472935.pdfIn PDF document text
    • http://oembag.com/uploads/files/202109090850381071.pdfIn PDF document text
    • http://dorrstrechy.cz/UserFiles/File/zowugegamexukunonuxideme.pdfIn PDF document text
    • http://stroykap.com/application/views/stroykap/userfiles/file/56745162668.pdfIn PDF document text
    • https://terracell.pt/images/file/32679968652.pdfIn PDF document text
    • https://mrdak.cc/uploadfile/files/mipatod.pdfIn PDF document text
    • http://ankaser.com/userfiles/file/67198599616.pdfIn PDF document text
    • http://usateatop.com/_upload/files/62563173268.pdfIn PDF document text
    • http://wajl.net/img/file/20219135920.pdfIn PDF document text
    • http://lovepetclinics.com/file_media/file_image/file/62909998516.pdfIn PDF document text
    • https://bdprescription.com/ci/userfiles/files/kipagiseg.pdfIn PDF document text
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f2b856566d---4139220154.pdfIn PDF document text
    • http://corse.annuaire-regional.com/ckfinder/userfiles/files/23816532814.pdfIn PDF document text
    • http://gift-founder.com/archive/upload/files/7574197168.pdfIn PDF document text
    • http://photo-preiss.com/upload_files/files/82944534408.pdfIn PDF document text
    • https://artbynela.com/uploads/file/putigalufedonadisiriso.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1614227ce9e50c---44270326453.pdfIn PDF document text
    • http://talcmanagement.com/uploaded_files/userfiles/files/44404012145.pdfIn PDF document text
    • http://vektor-bezpeki.com/userfiles/files/dasuwudojevet.pdfIn PDF document text
    • https://pre-www.bridge-academy.com/uploaded/ckeditor/files/56765639820.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=good+words+starting+from+pPDF 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_off0000ddae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDAE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f5c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5C0 16900 bytes
SHA-256: fc99df791d05e7e30435f5838fc4c0893d2f0bba030da2949153039d854f290f
font_02_sfnt_off000120f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120F0 10788 bytes
SHA-256: 8ceb28ef27857533a094e725dca0606e19dfe6a23836356849916cd06c8eb5a6

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