Malicious PDF — malware analysis report

Static analysis result for SHA-256 48423375629f0360…

MALICIOUS

PDF

76.8 KB Created: 2021-04-08 13:51:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 4f8569359e92e3f17462d0b99294d55d SHA-1: 3f06b11ddf7236da54c57b2e21853c2a53cce916 SHA-256: 48423375629f0360e63dd0a78f6064ddf805db7f0d60b483d0df08c2b51bd9fe
126 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as a phishing trojan and ML classifier indicated high maliciousness. It contains numerous embedded URLs, many pointing to disposable domains, and one specific URL `https://vilenefex.ru/strik?utm_term=c+sharp+string+reference+type` appears to be a primary lure. The document body is heavily obfuscated, preventing a clear understanding of its direct content, but the heuristic firings strongly suggest a malicious intent to redirect users to harmful sites.

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 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://vilenefex.ru/strik?utm_term=c+sharp+string+reference+type PDF link annotation
    • http://bizifemodefi.mygamesonline.org/review_of_organic_functional_groups_download.pdfIn PDF document text
    • http://carinsusa.info/spectrum_math_workbook_grade_8_free92cvz.pdfIn PDF document text
    • https://cdn.sqhk.co/kulamogo/8hhdPVk/roku_stick_channels_free.pdfIn PDF document text
    • https://cdn.sqhk.co/badalozebale/hehaics/heroes_warrensburg_specials.pdfIn PDF document text
    • http://tesekal.mygamesonline.org/molecular_biology_and_evolution_journal_abbreviation.pdfIn PDF document text
    • https://cdn.sqhk.co/noperizapewo/dhdVsjd/carve_pencil_art.pdfIn PDF document text
    • https://cdn.sqhk.co/rawerusiwala/1wDr3AR/44153759887.pdfIn PDF document text
    • http://zujewubowufonug.scienceontheweb.net/mk_pandey_analytical_reasoning_free_download.pdfIn PDF document text
    • http://goxamid.mypressonline.com/71197000589.pdfIn PDF document text
    • http://richmaya.site/infinity_comic_bookmt987.pdfIn PDF document text
    • http://tuvosudokalidu.scienceontheweb.net/kubernetes_architecture.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://xazawipobu.rf.gd/bejadesodedakituzoz.pdfIn PDF document text
    • https://s3.amazonaws.com/tokafanawa/17980016353.pdfIn PDF document text
    • http://fokezowo.epizy.com/dda_building_bye_laws.pdfIn PDF document text
    • https://s3.amazonaws.com/ponivotigegepub/47987279407.pdfIn PDF document text
    • http://solazagu.epizy.com/fuad_akhundov_guide.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/12c3e888-ef9f-4a83-9f87-d78080575051/ashrae_handbook_2001_fundamentals_ch._26.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c37f9caf-992a-403f-96ac-ac70259254ab/how_to_become_a_forensic_anthropologist.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f88e7b72-755b-4d3a-bf00-cfde5b8761cf/68757466712.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_off0000ec68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC68 5252 bytes
SHA-256: 15e99b8c24e041b5e0bcfc8f560e4ea9e988870b841cfe49f09fcd6ad71ee1ce
font_01_sfnt_off0000fe4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE4F 11468 bytes
SHA-256: c41a76c0a5ecf83d40280f91bac38d37b8e189f5894201c70405a2e49c743b70

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