Malicious PDF — malware analysis report

Static analysis result for SHA-256 58fc940e6a6d2e2c…

MALICIOUS

PDF

79.9 KB Created: 2021-02-28 13:42:07 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 496fc6decdcd9da01342582536bbf07f SHA-1: 566e110b67a2c857af744920b1da17e374e226ad SHA-256: 58fc940e6a6d2e2c93f620f7c867d17fcd766ca89dff531f1fc82a303985e9e5
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by a machine learning classifier and ClamAV, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, containing numerous external links, with a primary URL pointing to 'nipisod.ru'. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create PDFs from web content, which aligns with the link farm behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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.
  • 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://nipisod.ru/strik?utm_term=clasificacion+de+cuentas+contables+por+su+naturaleza PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4477863/normal_603ac4ac0899b.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4412151/normal_5ff89009027f0.pdfIn PDF document text
    • https://cdn.sqhk.co/bisuligiga/iYtxibf/ributinimoresuvat.pdfIn PDF document text
    • https://cdn.sqhk.co/keridola/fhdGQji/jarakajajujisiduginunol.pdfIn PDF document text
    • https://cdn.sqhk.co/rujiwujik/bDghieT/fun_things_to_do_seattle_winter.pdfIn PDF document text
    • https://xajerunufunofe.weebly.com/uploads/1/3/1/3/131378991/d88cafcfee1e.pdfIn PDF document text
    • https://cdn.sqhk.co/filemowa/388MqLR/27015994808.pdfIn PDF document text
    • http://zozagemidifisep.22web.org/l130_adjustment_program_free.pdfIn PDF document text
    • http://sitajejo.22web.org/cardiac_cycle_worksheet.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453142/normal_602f9f4a3a376.pdfIn PDF document text
    • https://tadesurirow.weebly.com/uploads/1/3/2/7/132711952/7652764.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
    • http://sipanokule.onlinewebshop.net/kovebovululidut.pdfIn PDF document text
    • http://rozopujonabesix.epizy.com/56819836102.pdfIn PDF document text
    • http://dudakitulefuteg.rf.gd/the_raven_cycle_opal_short_story.pdfIn PDF document text
    • http://gawuvuv.epizy.com/78892134741.pdfIn PDF document text
    • http://rizivubonulej.atwebpages.com/35718427434.pdfIn PDF document text
    • http://surusulo.rf.gd/yoshimitsu_beginner_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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e94b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE94B 5244 bytes
SHA-256: bff9437c4fcb558f474eb45fa69a50aec44635df6d7cbccf9781c923d97ab2c4
font_01_sfnt_off0000fb26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB26 12048 bytes
SHA-256: a10ab98781e01d9d96ab2c39b39fe2411cfe2f790b71c80b2b7090e7f90d8e5c
font_02_sfnt_off000121f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121F6 4324 bytes
SHA-256: ce7e2e230a41ba6fc2d7d2240890c8289d67876d84a3d076d67c0b48111c8230

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