Malicious PDF — malware analysis report

Static analysis result for SHA-256 52dd9b60e6b06d85…

MALICIOUS

PDF

71.8 KB Created: 2021-03-09 17:40:43 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 3f6bfb580f70d18e15e5a469d934315f SHA-1: d6f2d7dab178475c58c417a0f03ca05bf7a7a069 SHA-256: 52dd9b60e6b06d85f78f6666105c0631166af7564a650d8cd6f2c56596d050fc
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, with critical heuristics indicating it is part of a link farm or phishing scheme. The document body, though heavily obfuscated, contains references to 'online web to pdf converter free' and 'wkhtmltopdf', suggesting a lure. The presence of numerous external links, many pointing to PDF files, reinforces the link farm hypothesis, potentially used for SEO manipulation or to distribute further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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 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://zajinet.ru/award?keyword=online+web+to+pdf+converter+free PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4388833/normal_60400e2bb3516.pdfIn PDF document text
    • https://zosojelukik.weebly.com/uploads/1/3/1/8/131871698/54458.pdfIn PDF document text
    • https://mifadugusukar.weebly.com/uploads/1/3/5/3/135337027/8969216.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4484375/normal_601abbad58f5c.pdfIn PDF document text
    • https://dezijetide.weebly.com/uploads/1/3/4/8/134864221/jexumej.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4453108/normal_5ffd1b1de95d3.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/nitidadufetenu/english_vocabulary_worksheets_for_kindergarten.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/61eb5cfa-515c-4d1c-a27b-c730567277a8/bezutuzasapixagu.pdfIn PDF document text
    • https://s3.amazonaws.com/jojitagifuva/heraeus_group_annual_report.pdfIn PDF document text
    • https://s3.amazonaws.com/petuzutemixuvod/blank_itinerary_template.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1fd39628-e874-44c8-9728-c3a6d3645a5a/create_dynamic_json_object_c_newtonsoft.pdfIn PDF document text
    • https://s3.amazonaws.com/xuxifuzituwu/65068475339.pdfIn PDF document text
    • https://f8b57e9d-e272-4783-b6f5-6420e6b93425.filesusr.com/ugd/886b73_4ddc53d160ec4174b795b5b0a2d5a317.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/kiwopusafize/xofiwepufesogi.pdfIn PDF document text
    • https://s3.amazonaws.com/pulavokaxe/27150492542.pdfIn PDF document text
    • https://ed21222e-fee3-4fab-8b52-e2ddb7bb35ab.filesusr.com/ugd/e73fea_9103f1bbbb7547a7a1a5d681d5183787.pdf?index=trueIn PDF document text
    • https://adc0bc6f-2b4d-4951-bce0-9128d215fa34.filesusr.com/ugd/5ea4d5_0906385f2eea4448ab9150d9f87b3af2.pdf?index=trueIn PDF document text
    • https://d1b6b380-f15b-462b-86b5-0b089ba7d90d.filesusr.com/ugd/f99a33_1fa36de4867646e28ec764ac0ee8c723.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/degisapemifa/22807779906.pdfIn PDF document text
    • https://s3.amazonaws.com/fajujiju/22344920084.pdfIn PDF document text
    • https://510b81f6-be4e-4e40-9acf-3f60af495837.filesusr.com/ugd/5f226b_0e8b1b4c0b494b86b036aaf37cc59f97.pdf?index=trueIn 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_off0000dd1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD1A 5080 bytes
SHA-256: dcc9d99bb3201cf0ef5e83311b43ec7901a659f4e29316e1622c58e0f1125ba2
font_01_sfnt_off0000ee86.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE86 10192 bytes
SHA-256: 527ff4fc01d93a74cf4e22aa5c8af916f55ffe839c138ec3dc9a052e7c0dc468

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