Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9a2b404d82ac320…

MALICIOUS

PDF

69.3 KB Created: 2021-04-14 17:29:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 37dd981e99c39f13f7e0f553c65a7680 SHA-1: fdf23653164dc2f8c0306675eab2e4c81fcdce0d SHA-256: b9a2b404d82ac3206ca18bbcfe655f1ad7374a90cd226635fd2eaa64e040ba40
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. The heuristics indicate it is a link farm on disposable hosting, with multiple embedded URLs pointing to PDF files, suggesting a phishing or malware distribution attempt. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and 'Qt', indicating it was likely generated by a tool rather than being a legitimate document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://ambrose.edu/sites/default/files/webform/zateguzafafidefezibexe.pdf In PDF document text
    • https://www.visitsavannah.com/sites/default/files/webform/fukixuliwidopisoduzurapi.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/moridiwivomepagaduso.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/13471650610.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/17423244846.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/jilagofuzepev.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/rarapenebeku.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/taxevoxasubosiwugudabi.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/93477879009.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/jitebetususi.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/33269367294.pdfIn PDF document text
    • http://russian-ice-spb.ru/sites/default/files/webform/files/97818084314.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/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=timbco+425+specsPDF link annotation
    • https://community.princeton.edu/system/files/webform/luzixuganigofifabeja.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/nufimogunuzin.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/setokan.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/85824103047.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/42655509772.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_off0000d068.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD068 5176 bytes
SHA-256: 1ea5186b129c31824f5a5600af36351eed7d4a5177a86747da8209846bc61e34
font_01_sfnt_off0000e201.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE201 11868 bytes
SHA-256: 0e24c8528c09d0be8f3111adc76bb8337fe8cdb7a29e82e13d759a129aeb7570

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