Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5a9fa73cef80b5b…

MALICIOUS

PDF

68.3 KB Created: 2021-10-04 11:42:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 7ae888a39f5b5494c5b828a6cb8590e1 SHA-1: 9ceb4adacc205e6df2f9750cc5b76363d3ed8e36 SHA-256: b5a9fa73cef80b5b6e316100a583e4b5a0aea76c1745572c93a6234e0dffb276
126 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a high ML score and ClamAV detection, indicating malicious intent. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic suggests it is part of a link farm on disposable hosting, with numerous distinct hosts and UTM parameters, pointing towards a phishing or spam campaign. While no scripts were explicitly extracted, the nature of the PDF and the link farm activity strongly suggest it is designed to redirect users to malicious sites, likely for further exploitation or credential harvesting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://www.psk.com.au/application/third_party/ckfinder/userfiles/files/27953373772.pdf In PDF document text
    • https://machnik.net/ckfinder/userfiles/files/kokazogobesaliguzajit.pdfIn PDF document text
    • http://www.appsolutely.sg/wp-content/plugins/formcraft/file-upload/server/content/files/1615a26444969c---kowitikukekofonawojewazas.pdfIn PDF document text
    • https://mkontroll.hu/File/libobipesalose.pdfIn PDF document text
    • http://nurugelexport.com/ckfinder/userfiles/files/87598822040.pdfIn PDF document text
    • https://oolong-dining-co.com/webroot/editor-uploads/files/laxinugelulojipugelilodo.pdfIn PDF document text
    • http://deborahmayerlawoffices.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/96873013268.pdfIn PDF document text
    • https://umiyawoodworks.com/fckdb/userfiles/file/54794096929.pdfIn PDF document text
    • http://gloteckr.com/upload/editor/file/lemoxut.pdfIn PDF document text
    • https://tonmathunglan.vn/upload/files/23578935094.pdfIn PDF document text
    • http://chargooshads.com/images/upload/files/dowijabe.pdfIn PDF document text
    • http://kfnmsz.com/upfolder/e/files/20210927054322.pdfIn PDF document text
    • http://udaybharat.in/ckfinder/userfiles/files/fivuwivene.pdfIn PDF document text
    • http://esteel.my/userfiles/file/zimazilubilugaw.pdfIn PDF document text
    • http://kmbb.at/userfiles/file/76076039396.pdfIn PDF document text
    • https://sunrise-photon.com/upfiles/editor/files/3420995512.pdfIn PDF document text
    • http://www.alexgis.com/siteuploads/editorimg/file/komabateba.pdfIn PDF document text
    • https://escolaalfa.com/userfiles/file/gojefigajatuxanoxu.pdfIn PDF document text
    • http://hissekurban.com/resimler/files/fujes.pdfIn PDF document text
    • http://shopgraeagle.com/ckeditor/uploads/files/36860721984.pdfIn PDF document text
    • http://slhospital.com/upload/fckeditor/file/47004994634.pdfIn PDF document text
    • http://fitviewer.biz/files/file/suserexisabajedomu.pdfIn PDF document text
    • https://amgaa.org/temp/files/42092822260.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=computing+system+definitionPDF 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_off0000af9f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF9F 14408 bytes
SHA-256: c4c0150490f622da2c84d4ac8a2bfa7a1e9f3ebda5912e5e55c3880c3cae1fce
font_01_sfnt_off0000d347.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD347 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000eb5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB5E 10780 bytes
SHA-256: 504efadfd10771978649fd8183385ba05ef96eed2143d62232cd0c5720afcb39