Malicious PDF — malware analysis report

Static analysis result for SHA-256 40b88ed5f33f1bd6…

MALICIOUS

PDF

69.9 KB Created: 2021-04-18 12:00:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 4a7734bd1ea8e416e4c4e8c9a449dd3d SHA-1: a640dc880950cfb1e3cf2eb3f0e6f85382779345 SHA-256: 40b88ed5f33f1bd65b425dee65f25f0d289d22d2af1a1cc62cbae8c8ded2477c
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which are hosted on disposable domains or appear to be part of a link farm, suggesting a phishing or malware distribution scheme. The document body, though heavily obfuscated, contains metadata related to wkhtmltopdf, indicating it was likely generated programmatically to appear as a resume, a common lure for spearphishing attachments.

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://www.enwidth.com/sites/default/files/webform/resumes/paxifufal.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/71027525942.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/tekuxegejarikuferibo.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/34869944823.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/41266633523.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/futexapepunuvanujom.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/dekif.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/41345860665.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/lolavojirubopikumu.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/jinez.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/27880179426.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/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=qu%25C3%25A9+caracter%25C3%25ADsticas+presenta+un+ensayoPDF link annotation
    • https://drones.princeton.edu/system/files/webform/voretazejujuwewoz.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/vabomabexajamoja.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_off0000d243.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD243 5256 bytes
SHA-256: bb33bc0a0dbd000d264d12f7fd82762b4aabf7fd70a4db714cd19696a1ce0d09
font_01_sfnt_off0000e3f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3F2 11136 bytes
SHA-256: 9a183e5e9645d40a3824634908c770de2ff50a81157d84b538d06963a10aea18

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