Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4cf13928b508a5f…

MALICIOUS

PDF

84.7 KB Created: 2021-04-23 23:59:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 1f47053bb4a1e8a4ae3a410a74b6af8e SHA-1: 7cc4d062ede749ff8a1d8f099dabca99a291b7c9 SHA-256: c4cf13928b508a5f14566ef3785c13eb6a69fcef6b5e5850a5711060aaa6c696
126 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many of which point to disposable hosting and are likely part of a link farm designed to redirect users. The primary malicious URL identified is https://xajibur.ru/strik, which is likely used to deliver a phishing or malware payload. No scripts were extracted, but the presence of multiple external URIs and the link farm heuristic strongly suggest a phishing or redirection attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://xajibur.ru/strik?utm_term=is+emdr+good+for+ocd PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4457862/normal_6046d1de9cd75.pdfIn PDF document text
    • https://puwawegolawibot.weebly.com/uploads/1/3/2/6/132682739/a85ddf29.pdfIn PDF document text
    • https://nukubutanedun.weebly.com/uploads/1/3/5/3/135309192/fetiriki.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4462986/normal_5fe4f5875b156.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365608/normal_6067a49fba791.pdfIn PDF document text
    • https://xajixaze.weebly.com/uploads/1/3/2/3/132302973/pirojibiborodakabef.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4392215/normal_605c975abbc3b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4423188/normal_60139c246c4f3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4408709/normal_601ab01c2eef1.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4448328/normal_6004fcdee82c2.pdfIn PDF document text
    • https://bezumovepefare.weebly.com/uploads/1/3/5/3/135337037/f5f80.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/cadfc348-77fd-411c-aab0-84d34a13a495/95238746117.pdfIn PDF document text
    • https://920f4c01-5fd6-4c40-8b27-b99972fecb60.filesusr.com/ugd/d63aaf_2e33076cdd38457a84f4a3147f04ba6c.pdf?index=trueIn PDF document text
    • https://9fbeb193-358d-48fe-b9d9-45f8b63f6b3c.filesusr.com/ugd/ab67b9_f28ad854e72748b5b60a0c35ba8568f6.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/siwixomudit/behind_enemy_lines_2006.pdfIn PDF document text
    • https://s3.amazonaws.com/muvevanepen/27397115219.pdfIn PDF document text
    • https://s3.amazonaws.com/baposivarabuj/nizuxusagadij.pdfIn PDF document text
    • https://s3.amazonaws.com/nedijowewoded/android_nougat_developer_options_explained.pdfIn PDF document text
    • https://s3.amazonaws.com/kobivimelelo/68168500701.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/69b55cbb-28ab-41b1-a10b-f20c673cb160/puwaju.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/bf8f26bf-e751-43b0-bd14-d09610cc96b1/97316050443.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3078017e-a628-408e-b38d-67bbe4b37f44/how_to_edit_a_logo_in_illustrator.pdfIn PDF document text
    • https://0df6220b-9630-4647-aab6-0d9db69b9d59.filesusr.com/ugd/8b97dd_2764e419948c4d928bb43c08188a4a57.pdf?index=trueIn PDF document text
    • https://doi.org/10.1002/cpp.2120In 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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f840.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF840 5036 bytes
SHA-256: d5904c423054a9807ad96a0ec1e2b8ddc7980a093cba989605b5409038fd03e5
font_01_sfnt_off0001094e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1094E 11348 bytes
SHA-256: 2dccd2cd412cb6389aa8151b9b6f36d56ae2cb00eddc08ca824379dfec03b2bc
font_02_sfnt_off00013076.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13076 16060 bytes
SHA-256: 2173a1880e9f774f759393e7d0d28dda91d04d8a3eae6bea41b822770b343b90