Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b67541780174297…

MALICIOUS

PDF

76.3 KB Created: 2021-04-25 20:31:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: b2921807e02e3f5b104132a8647e04df SHA-1: 5ba8cc97246ac8fc48c3d07307a130140fa67cf4 SHA-256: 4b67541780174297167d5a3e2b9e2540b46fd06dddbf840c587073bacf06d3a6
126 Risk Score

Malware Insights

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

This PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to disposable domains or are part of a link farm, suggesting an attempt to redirect users to malicious sites. The document body, though heavily obfuscated, contains text related to 'Best books for nuclear and particle physics' and mentions 'wkhtmltopdf', indicating a lure to disguise the malicious intent. No scripts were extracted, but the PDF structure and embedded URLs strongly suggest a phishing or redirection attack.

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 http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/31843799141.pdf In PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/14219433733.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/zoxajetuvu.pdfIn PDF document text
    • https://www.visitsavannah.com/sites/default/files/webform/nodarinit.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/40110328039.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/42535902170.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/pefusoxewirevujilo.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/tojawi.pdfIn PDF document text
    • https://www.termis.org/system/files/webform/dexifivoneput.pdfIn PDF document text
    • https://www.afscme65.org/system/files/webform/52844377902.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/21411595718.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
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=best+books+for+nuclear+and+particle+physicsPDF link annotation
    • https://www.healthdata.org/sites/default/files/resumes/muvebijamalixodimobowase.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/44438097533.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/61493424170.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/ruwitik.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_off0000de7b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE7B 5480 bytes
SHA-256: ba89ec805576753bafeb2992530ab3a0eb1d00e4ab6b2ee99258d045d0ec4baa
font_01_sfnt_off0000f11a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF11A 10844 bytes
SHA-256: 2521ea1b2584eb260eed32b213da79a84fafa4dc0bc5946ada3d335934b68f63
font_02_sfnt_off00011635.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11635 4324 bytes
SHA-256: d1f4a20f0e35a0564be54678b929bb8c711862c507f070c2b9a6abea8daf4378

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