Malicious PDF — malware analysis report

Static analysis result for SHA-256 c87ae5d368c4e9ac…

MALICIOUS

PDF

72.0 KB Created: 2021-04-26 22:07:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-17
MD5: 532ef7a520e21b36acd91dfa03eda8f8 SHA-1: e5d57a526f6adddca87ae3071cbbe685b3bbb677 SHA-256: c87ae5d368c4e9ac6da4447a8b2c2911627926d80e4402e3137174b3bbbd11e3
126 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to disposable hosting and are part of a link farm, as indicated by the PDF_SEO_DISPOSABLE_LINK_FARM heuristic. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. While no scripts were explicitly extracted, the structure and heuristics point towards a malicious PDF designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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.natsihwa.org.au/sites/default/files/webform/setafemamuf.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/65047245793.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/99469138220.pdfIn PDF document text
    • http://www.pacificsportfraservalley.com/sites/default/files/webform/zasadavatemomafupe.pdfIn PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/vetasitumuwogemukuruv.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/94808830073.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/85138354947.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/wavunivuzabanovomid.pdfIn PDF document text
    • https://europa-ts.ru/sites/default/files/webform/81905598419.pdfIn PDF document text
    • https://www.visitsavannah.com/sites/default/files/webform/fukixuliwidopisoduzurapi.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/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=graphing+inequalities+in+two+variables+worksheetPDF link annotation
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/wosevojowavinojefe.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/45540448673.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/luzixuganigofifabeja.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/10713621665.pdfIn PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000da7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA7D 5596 bytes
SHA-256: bd0df18b1d3462652f280b9cd6979a68ea2a1da7cd1167debc13c7f1ec8889e8
font_01_sfnt_off0000ed94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED94 11336 bytes
SHA-256: dd2eb2c258f4d8595e992b643d15761ba6569dd196b62cb51d11078d170be4c9