Malicious PDF — malware analysis report

Static analysis result for SHA-256 bc7403d1c4e5ae80…

MALICIOUS

PDF

66.1 KB Created: 2020-11-18 23:21:18 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: 527d67834cdb730c80e62b47bc05d3d4 SHA-1: 50ece2e6ba518f798d79edec0e98e04a52d93c68 SHA-256: bc7403d1c4e5ae800c7a904ef1c853acff44306539957fffc3c911a97653a6fc
156 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file contains numerous external links, with a critical heuristic identifying it as a 'PDF_SEO_LINK_FARM'. One of the primary external links, 'https://traffset.ru/strik?utm_term=ejercicios+de+alcanos+y+cicloalcanos', is suspicious and likely leads to a malicious site. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create SEO-optimized content, further supporting the link farm hypothesis. The presence of embedded URLs and the ClamAV detection indicate malicious intent.

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://traffset.ru/strik?utm_term=ejercicios+de+alcanos+y+cicloalcanos PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4388432/normal_5f90d87454021.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4481988/normal_5fb021cb8baff.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366408/normal_5f8725c66d2bb.pdfIn PDF document text
    • https://vevinobe.weebly.com/uploads/1/3/4/4/134487659/79a600.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4378167/normal_5f94d827451e2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368467/normal_5f8a2c3d0f3c0.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://s3.amazonaws.com/kewakuko/29344784523.pdfIn PDF document text
    • https://s3.amazonaws.com/pokixovuxik/adobe_acrobat_old_version_for_android.pdfIn PDF document text
    • https://s3.amazonaws.com/pukasojalu/chemistry_penny_lab_answer_key.pdfIn PDF document text
    • https://s3.amazonaws.com/tokafanawa/79171030459.pdfIn PDF document text
    • https://s3.amazonaws.com/felasorarabipis/personal_development_module.pdfIn PDF document text
    • https://s3.amazonaws.com/remavuj/dover_sherborn_aspen_login.pdfIn PDF document text
    • https://s3.amazonaws.com/bisegilupuf/light_guide_systems_costs.pdfIn PDF document text
    • https://s3.amazonaws.com/suzeduselu/68855463309.pdfIn PDF document text
    • https://s3.amazonaws.com/biwuwukesazef/xanofilifajuj.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b902.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB902 4776 bytes
SHA-256: 4bb618d2c9274d44ea476fc4871302e04af3a013a797101cdb76197e3dc9a2cc
font_01_sfnt_off0000c943.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC943 10492 bytes
SHA-256: cd604272a09b9106769ad2da572127d89bbe20d4ef4f4fc8881b0e5b7b27cf3a
font_02_sfnt_off0000eb9b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB9B 4324 bytes
SHA-256: 05d2457133b820fa77aa358e30e9acfbad3f04c46ced9a37296d9311117db176

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