Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b8cd98bffb695f6…

MALICIOUS

PDF

72.9 KB Created: 2021-04-20 02:48:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-30
MD5: 546cca5f85c0624181d50b2fe37772db SHA-1: 5d566eee11ed03db5c1e898372d0ec11afec517b SHA-256: 5b8cd98bffb695f6e7a3a50846fe5645efd1e2a94938c6e77dd14387d23dece9
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm on disposable hosting, likely to redirect users to malicious sites. Although no scripts were explicitly extracted, the PDF structure and embedded URLs suggest an attempt to lure users through deceptive content, aligning with spearphishing tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://natsihwa.org.au/sites/default/files/webform/46250275999.pdf In PDF document text
    • https://aboss.by/sites/default/files/webform/zivexovoburowunaxomenip.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/41164207556.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/sabaw.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/60165950635.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/kixeje.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/95374483905.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/viwiredozilopuvotudulufez.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/balulata.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/woluweweketasuzizolog.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/mufuwujaxerafesa.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/72808970040.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/fzgW7-mxBc0/uplcv?utm_term=old+yeller+book+authorPDF link annotation
    • https://community.princeton.edu/system/files/webform/4167827641.pdfIn PDF document text
    • https://umatter.princeton.edu/system/files/webform/requests/72435273025.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/fujixedapilevunagujos.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://ns.adobe.com/xap/1.0/rights/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_off0000dfed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFED 5068 bytes
SHA-256: c7e3ab975b2ba6870878251df50af27c67bfac32e37abfe3d79bdf1fcdfb8aa4
font_01_sfnt_off0000f128.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF128 10696 bytes
SHA-256: 9e564d0307d40305a3e50b1ca66d79539fe968d244908162d6f5bdb40689d798

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