Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b950d8f044471d6…

MALICIOUS

PDF

67.9 KB Created: 2021-04-25 20:05:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 620a24cd3217151c168f3910737961e4 SHA-1: 2c3d606b0e11e29dc75f4cc3f75b244d252cd736 SHA-256: 4b950d8f044471d60cca5d875da86992587b50328753cc79ba2ec5dee6c21969
126 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, indicating a high likelihood of malicious intent. The presence of numerous external URIs, many pointing to seemingly benign domains but potentially serving as part of a link farm or redirection scheme, suggests an attempt to obscure the true destination. While no scripts were explicitly extracted, the PDF structure and the ML/ClamAV detections point towards a phishing or malware delivery mechanism, likely initiated via a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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.jwico.com/sites/default/files/webform/49109440539.pdf In PDF document text
    • https://www.newburghgroup.com/sites/default/files/webform/resumes/tikijoti.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/gafazibo.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/17015803.pdfIn PDF document text
    • https://www.newburghgroup.com/sites/default/files/webform/resumes/41319995155.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/11364316539.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/zMnd8XtcwSM/uplcv?utm_term=graphic+novels+for+middle+schoolerPDF link annotation
    • https://community.princeton.edu/system/files/webform/kabajizonen.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/vifixofixif.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/janoruzafasolefixos.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/90369837207.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/ninavixokamorul.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/zupedofijemurak.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_off0000cd04.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD04 5484 bytes
SHA-256: d587e48e7989879f619427b4a39109259a23da9a14b7e38ac5ecf0c4b342eaa4
font_01_sfnt_off0000df8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF8B 10400 bytes
SHA-256: e43254cfcac22d648704a64ff812ec1ba0c0176b4e2466f8e32327a9885d7125

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