Malicious PDF — malware analysis report

Static analysis result for SHA-256 e4b1b8a085849b23…

MALICIOUS

PDF

70.9 KB Created: 2021-02-22 19:10:41 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: b5cfcf158e9ee33fee9afc1adcf56ca6 SHA-1: 733b24536eeac952302e5ae053d542293c61e245 SHA-256: e4b1b8a085849b2326639c695cccbf5852b718efab080854eb452b6e00914789
184 Risk Score

Malware Insights

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

The sample is a PDF file flagged as malicious by multiple heuristics, including a critical alert for linking to known malicious redirector infrastructure. The embedded URL points to 'yafferge.ru/strik', which is identified as a malicious redirector. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and a date, suggesting it was generated programmatically. The presence of embedded URLs and the critical redirector link strongly indicate a phishing or malware distribution attempt.

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/strik?utm_term=define+topic+sentence+apex In PDF document text
    • https://cdn.sqhk.co/dilizilozok/ujjiaRO/directv_guide_not_working_2018.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4481847/normal_5ff3f3728cd5b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393019/normal_6011fb3918335.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4383295/normal_5ff6090d8ad5b.pdfIn PDF document text
    • http://legendnat.space/javascript_function_tutorial_with_examplesihnav.pdfIn PDF document text
    • http://lorenbayi.com/vapewudisixowubuwavaf708.pdfIn PDF document text
    • https://cdn.sqhk.co/vixawutozama/bij24Gp/pododedimidoja.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4454421/normal_5fcdf1460f439.pdfIn PDF document text
    • http://vzruvayarttraff.xyz/sigexibo2dbjg.pdfIn PDF document text
    • http://lnstagramverifycentre.com/lagu_rewrite_the_stars_cover_sterre7g2u7.pdfIn PDF document text
    • http://rodupokikoxozed.22web.org/pogikanagivug.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/paxivogedewilu/boguruzidefebunijalerix.pdfIn PDF document text
    • http://kuminatunajovop.epizy.com/tagatizerokofikobidojules.pdfIn PDF document text
    • http://kunipotow.epizy.com/dobixobowukula.pdfIn PDF document text
    • https://s3.amazonaws.com/divelatoxa/ecb_guide_to_internal_models_general_chapter.pdfIn PDF document text
    • http://gigivixegaxun.epizy.com/yooka_laylee_impossible_lair_achievement_guide.pdfIn PDF document text
    • https://s3.amazonaws.com/boxujetanonikuv/flor_de_leyendas_alejandro_casona_descargar.pdfIn PDF document text
    • http://danokob.epizy.com/princeton_review_gre_verbal_workbook.pdfIn PDF document text
    • https://s3.amazonaws.com/padanivozeb/ragnarok_eternal_love_reddit_guide.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_off0000d734.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD734 4948 bytes
SHA-256: 9e04987882d3f362afe2fc985c29cb07d8634b953d774faca3aa10a6454c9bb0
font_01_sfnt_off0000e831.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE831 11272 bytes
SHA-256: c3f131c63bdd60eea87b192f60387131a016f32ae8ecfc70fcbc6d1e03b98fe1

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