Malicious PDF — malware analysis report

Static analysis result for SHA-256 1685539ad391bf73…

MALICIOUS

PDF

80.2 KB Created: 2020-11-30 20:12:05 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-26
MD5: 644bc91640ab2ac1111682eb0d3dff8f SHA-1: b3b4a16a409e6652353c21325e2e89e1f04dad73 SHA-256: 1685539ad391bf734197c80404d5f678d74d4040d1b35241ea4fc34ebd96ae43
156 Risk Score

Malware Insights

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

The sample is a PDF document that leverages a "link farm" technique by embedding a large number of external links, disguised as a "bootstrap css cheat sheet". The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or SEO spam. While no scripts were explicitly extracted, the PDF structure and embedded URIs suggest it's designed to redirect users to potentially malicious websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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 contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://trafficel.ru/aws?utm_term=bootstrap+css+cheat+sheet PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4409997/normal_5f96a6ba8bf0b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4404741/normal_5fa41eb585c73.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370525/normal_5fb5b0e983378.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4404500/normal_5faa582c7edac.pdfIn PDF document text
    • https://vadurevagide.weebly.com/uploads/1/3/3/9/133999829/4525621.pdfIn PDF document text
    • https://togitarusufojir.weebly.com/uploads/1/3/2/6/132681229/3936009.pdfIn PDF document text
    • https://tenasedoba.weebly.com/uploads/1/3/4/3/134333827/9890704.pdfIn PDF document text
    • https://mebitulipavore.weebly.com/uploads/1/3/4/3/134339985/8133593.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/b2b656cd-9a5a-40ea-8fd5-67566a56da7d/56607508299.pdfIn PDF document text
    • https://static1.squarespace.com/static/5fbce344be7cfc36344e8aaf/t/5fbf50bd1972c46e3c957470/1606373565311/dilotirelabumuzipido.pdfIn PDF document text
    • https://static1.squarespace.com/static/5fbce344be7cfc36344e8aaf/t/5fbd10ce81523578e9ba99c2/1606226126795/grades_garden_portal_de_padres.pdfIn PDF document text
    • https://static1.squarespace.com/static/5fc298325e8e827d4298aebe/t/5fc4fec0f3de5e49b5021f08/1606745793117/21763668448.pdfIn PDF document text
    • https://static1.squarespace.com/static/5fc01ccfc14dfd36feed28e9/t/5fc197a5f8cdb769c61fa945/1606522789488/risd_housing_portal.pdfIn PDF document text
    • https://static1.squarespace.com/static/5fbce344be7cfc36344e8aaf/t/5fbf5721e6d49a06bb88ee06/1606375202730/sten_gun_plans.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/dd9663d3-bbff-4f32-88aa-2c186fd8c7a5/85272104470.pdfIn PDF document text
    • https://static1.squarespace.com/static/5fbce344be7cfc36344e8aaf/t/5fbe00ddeaf37e3b64623c9f/1606287582399/miges.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_off0000fd0e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD0E 5040 bytes
SHA-256: 34b22466ccb449f2f12a50f249856b372dbbd72f9a6dedc898aa5d6840e35aae
font_01_sfnt_off00010e2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E2C 10928 bytes
SHA-256: a9bfbad7400895b08901730337775e1dca61804d063730864207a59e054093a0

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