Malicious PDF — malware analysis report

Static analysis result for SHA-256 d5d578321d6481af…

MALICIOUS

PDF

63.7 KB Created: 2021-02-10 17:46:56 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 8b36c3656849f543d09e4c40d4362394 SHA-1: 4bc082385a5763cde47dc536045c1a414bb7019c SHA-256: d5d578321d6481af71c9cfef4cb711486d52aacde662508d8bcc0e263b16420a
96 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by an ML classifier. It contains a heuristic firing for a 'PDF_SEO_LINK_FARM' which indicates the presence of numerous external links designed to appear as search engine optimized content. The embedded URLs and the document body, though heavily obfuscated, suggest a pattern of redirecting users to a large collection of other PDF files, likely for malicious purposes such as ad fraud or distributing further malware. No scripts were extracted, but the structure points towards a link farm attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 4

  • 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.
  • 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://druttle.ru/wb?keyword=aieee%202007%20physics%20solutions%20pdf PDF link annotation
    • http://govnosiakxws.online/kaplan_nursing_entrance_exam_study_guidevl1zc.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4392439/normal_5fd688d45408a.pdfIn PDF document text
    • http://cybety.xyz/talking_angela_unlimited_money_apkk2id1.pdfIn PDF document text
    • http://sluzhba1.net/languidez_en_inglstb6n2.pdfIn PDF document text
    • http://itclick.pro/agama_islam_di_indonesiacuza9.pdfIn PDF document text
    • http://expressday.online/3974397821634vce.pdfIn PDF document text
    • http://simultaneously.space/kipobifetukumililaledexl3o58.pdfIn PDF document text
    • https://loratabupufedev.weebly.com/uploads/1/3/2/6/132695903/2876322.pdfIn PDF document text
    • https://risixugetiso.weebly.com/uploads/1/3/5/3/135317557/xisagifuganizitigu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4455405/normal_601d056af0576.pdfIn PDF document text
    • https://vezutokabev.weebly.com/uploads/1/3/4/7/134758566/4202099.pdfIn PDF document text
    • http://ygrash.website/ocean_fortune_apkd8uak.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/xixonu/67521366169.pdfIn PDF document text
    • https://s3.amazonaws.com/faduxodiwo/datasheet_arduino_mega_2650.pdfIn PDF document text
    • https://s3.amazonaws.com/ximupuv/free_blogger_template_music.pdfIn PDF document text
    • http://dufexisoji.rf.gd/shiva_cartoon_hd_full_movie.pdfIn PDF document text
    • https://s3.amazonaws.com/zafijukopa/solving_logarithmic_equations_worksheet_answer_key.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_off0000bda2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDA2 5380 bytes
SHA-256: 084ad9e5be0ab1471d5855070fd8734de360b56ed93a8bc5eab3360ecb458117
font_01_sfnt_off0000d00d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD00D 9924 bytes
SHA-256: 53ad7f4cc9b5565996f970d89ed768e94dbca457e540242d0888b8b0becd3e37

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