Malicious PDF — malware analysis report

Static analysis result for SHA-256 856b3e6b67ea2e3d…

MALICIOUS

PDF

84.8 KB Created: 2021-04-06 23:51:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 6572b4222842e267d4328555e6167ea5 SHA-1: de65f025babd152c133f6a1e5954f82424103401 SHA-256: 856b3e6b67ea2e3da2295b9bf6b9c1ab62b5ff4f91c523f17032473618b63144
126 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The document body, though heavily obfuscated, contains references to 'architecture articles pdf' and uses wkhtmltopdf, suggesting a lure. The presence of numerous external URLs, many pointing to disposable domains or link farms, further supports a phishing or malware distribution scheme. No scripts were extracted, but the overall structure and heuristic firings point to a malicious PDF designed to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://web.liderpapel.com/sites/default/files/webform/kivalin.pdf In PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/xikamiwaboloz.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/moridiwivomepagaduso.pdfIn PDF document text
    • https://www.termis.org/system/files/webform/67198091979.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/96040264728.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/95866450710.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/80507347088.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/44437875789.pdfIn PDF document text
    • https://europa-ts.ru/sites/default/files/webform/81905598419.pdfIn PDF document text
    • http://www.pacificsportfraservalley.com/sites/default/files/webform/newusagolepilukakatukus.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/25507329945.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/fadubapep.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/10891008032.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • http://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=architecture+articles+pdfPDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/lezedatabamivija.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010183.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10183 4900 bytes
SHA-256: 352d551560a83c789b1a0a3b5d7b0b175c56b30c637c68509a812c7608f8a9a3
font_01_sfnt_off00011235.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11235 11552 bytes
SHA-256: 82d111e8001d2709f1d0f1046564e38b0fea95a142ea8e74de1d9049d274ed4a
font_02_sfnt_off0001380d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1380D 4324 bytes
SHA-256: cd94ef65598b1866d0653cdd88243d989fd81359c0e770c2d3a4858f1c2f6d34

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