Malicious PDF — malware analysis report

Static analysis result for SHA-256 e4c3b691d258221f…

MALICIOUS

PDF

87.0 KB Created: 2021-03-22 19:47:14 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-10
MD5: d37addcba23c89b1a81fedf20ee03e97 SHA-1: 409407926c2bb6b6609ed244ce0373abe3e50d63 SHA-256: e4c3b691d258221f3b079ff9e8970f84b932bb21585854b3d24206850e47e9d3
126 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, with a high-risk score. It contains an embedded URI pointing to 'vilenefex.ru', which is likely a phishing or malware distribution domain. The PDF's content, though heavily obfuscated, appears to be a lure related to 'Cornell law grading scale'. The presence of multiple external URIs and link farm heuristics suggest a malicious intent to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 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/wix?keyword=cornell+law+grading+scale PDF link annotation
    • http://digerutejonoju.22web.org/ain_t_misbehavin_sheet_music_fats_waller.pdfIn PDF document text
    • https://cdn.sqhk.co/jarixizotib/iipQjc7/tezezokamibamovibewijeful.pdfIn PDF document text
    • https://cdn.sqhk.co/buwaxaxodi/iO7Bpu0/zemepopuwulukedimazet.pdfIn PDF document text
    • https://cdn.sqhk.co/rugugojeba/kWhggdB/91976339034.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://tumozuj.epizy.com/36796095973.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4c4de172-e835-487a-a240-a8c2250fabb0/shadowrun_hong_kong_weapons_list.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6379ce49-6ab0-4728-a189-c6e304a0c77e/97073964736.pdfIn PDF document text
    • http://gakifok.rf.gd/honda_excell_2400_pressure_washer_manual.pdfIn PDF document text
    • http://nidemavaguwagev.rf.gd/android_root_app_manager.pdfIn PDF document text
    • https://s3.amazonaws.com/wizomoravazub/19093950043.pdfIn PDF document text
    • http://goxebobepi.epizy.com/14001313634.pdfIn PDF document text
    • http://ralepixevoz.epizy.com/apollo_twin_mkii_vs_apollo_x6.pdfIn PDF document text
    • http://zunebitalubale.rf.gd/private_facebook_video_online_free.pdfIn PDF document text
    • http://zemesimeboxi.epizy.com/chrome_flash_settings_permanent.pdfIn PDF document text
    • https://s3.amazonaws.com/zukogi/vewumivewinef.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4464e3a5-0a89-457e-95f8-d0113f70e660/91410631373.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ddd92a83-be69-4fad-827b-20b48a8903ef/medios_de_comunicacion_mas_utilizados_actualmente.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4b56b474-3b93-4964-ae78-8e9fa52850cf/trigonometric_formula_for_area_of_a_triangle.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_off000117b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117B5 5104 bytes
SHA-256: cbdb0bfba6903e949b6c2af9b77188b14c1af5e6e78fc54bacf026f4364996f8
font_01_sfnt_off0001292b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1292B 11176 bytes
SHA-256: ae9929fce1ff54ccb19fc7324a0e5682dce104f8afb7c4aee6880ee5016dcc08

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