Malicious PDF — malware analysis report

Static analysis result for SHA-256 9d8d50fa439f7831…

MALICIOUS

PDF

70.6 KB Created: 2020-12-31 00:51:22 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-15
MD5: a70c4c8c0c0296a40dc64b6728d4891b SHA-1: 7c531962aaea34f37fb2604b1a5e595a7115808a SHA-256: 9d8d50fa439f7831cc99abfbacfb458a06aa9acdc9c435c1c82dec4ebf3bd0b2
186 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm or phishing operation. The document body, though heavily obfuscated, contains text related to 'virtual classroom rules and expectations', which is likely a lure to direct users to malicious URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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 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.
  • 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://trafftec.ru/strik?utm_term=virtual+classroom+rules+and+expectations PDF link annotation
    • https://porimejonawi.weebly.com/uploads/1/3/4/3/134368737/4945728.pdfIn PDF document text
    • https://cdn.sqhk.co/tipefimex/ij0Neji/58005488335.pdfIn PDF document text
    • https://vesanawe.weebly.com/uploads/1/3/4/6/134602832/2927388.pdfIn PDF document text
    • https://xojisige.weebly.com/uploads/1/3/1/6/131637148/mosikeriz-bidepeb-tizon-nenefaxupi.pdfIn PDF document text
    • https://gowoxavakuf.weebly.com/uploads/1/3/4/7/134702457/ziseb_pifiworamexavu_jularamux.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368953/normal_5fae2109d0e80.pdfIn PDF document text
    • https://vukivogo.weebly.com/uploads/1/3/5/3/135329669/jikojijaxu.pdfIn PDF document text
    • https://cdn.sqhk.co/nupegefozub/hdghBcg/muripibuwefubi.pdfIn PDF document text
    • https://digokevun.weebly.com/uploads/1/3/4/7/134747151/f234e1.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/setaxilitozuko/bibiliya_yera_mu_kinyarwanda.pdfIn PDF document text
    • https://s3.amazonaws.com/jasadavebaga/logic_circuits_questions_and_answers.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e52b672b-9c18-4118-9cd5-7db10c764936/pance_prep_pearls_free_download.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d41bb250-ed44-4433-8671-d1f682d32417/37545682303.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/145a6252-f2b2-432e-aa3d-3feb1fd4243e/mijurosemef.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_off0000d713.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD713 5252 bytes
SHA-256: 746ec01782c290910c4f480edd7c610f21107df0531c6769061a3c6ddbee35fc
font_01_sfnt_off0000e8d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8D9 10604 bytes
SHA-256: f296dcb00f448bd22d01455c5e50a2a8464296239756f67e51181106bf8892c4

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