Malicious PDF — malware analysis report

Static analysis result for SHA-256 850a79751442f586…

MALICIOUS

PDF

69.0 KB Created: 2021-01-26 10:39:13 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 566b763f32345e1183c22f46a5acbe3f SHA-1: 94c659011f1fb760d61f4044d423b3c3196ae806 SHA-256: 850a79751442f586da3d1d40eebc6d5f35c7fe042f28fe179a15d2bbf518b9bf
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm on disposable hosting, with numerous external URIs pointing to potentially malicious domains. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create malicious PDFs. The presence of embedded URLs and the link farm heuristic strongly suggest the document's purpose is to redirect users to external sites, likely for phishing or malware delivery.

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://jacksth.ru/123?utm_term=miami+valley+ctc PDF link annotation
    • https://metonokosaza.weebly.com/uploads/1/3/2/6/132681587/3997012.pdfIn PDF document text
    • https://lewobagapu.weebly.com/uploads/1/3/4/6/134666085/4ea660a02b4.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4503050/normal_5fe5d5aee6020.pdfIn PDF document text
    • http://bofajazikevag.22web.org/auditoria_de_sistema_de_informacion.pdfIn PDF document text
    • http://vsspb.ru/98417526007zhomv.pdfIn PDF document text
    • http://donuliwobem.iblogger.org/metal_roofing_sheets_dealers.pdfIn PDF document text
    • https://kafedujewerom.weebly.com/uploads/1/3/4/6/134622586/e1e8f97cef4.pdfIn PDF document text
    • http://nicepics.xyz/crossfire_wallpapers_hdijx5l.pdfIn PDF document text
    • http://zupinuxuxodu.iblogger.org/59341230839.pdfIn PDF document text
    • https://bekodezu.weebly.com/uploads/1/3/1/8/131856725/kulemusune.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4471960/normal_5fd660a87d735.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://bakotege.rf.gd/puxivanezejife.pdfIn PDF document text
    • http://rojapamun.epizy.com/2016_cadillac_xts_service_manual.pdfIn PDF document text
    • https://s3.amazonaws.com/baxekojojexusol/worship_songs_audio.pdfIn PDF document text
    • https://s3.amazonaws.com/tupofelasujewas/tinojubososudebumirikum.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_off0000d2e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2E4 4840 bytes
SHA-256: df42ce15b917239edfd9958c6db3e43541a72e1b509a5a16a66527344ce909e9
font_01_sfnt_off0000e363.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE363 10348 bytes
SHA-256: 73c84ecd10df2b8e4a46b7b6f5a8f266d62e9f19a7ce5799919faf6a04db567d

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