Malicious PDF — malware analysis report

Static analysis result for SHA-256 0c4c8d1597f3364f…

MALICIOUS

PDF

81.2 KB Created: 2021-05-02 07:16:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-13
MD5: 8e4570c68e437839f5d80ee6dca61ec3 SHA-1: e197901a693f01a170370fb0f603f2cc6116a05d SHA-256: 0c4c8d1597f3364f73416a6638e03f0aaa12b79b4d9db8ef0f1af517f1e8ef13
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to disposable domains, indicating a link farm or SEO spam operation. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution. While no scripts were explicitly extracted, the PDF structure and embedded URIs are indicative of techniques used to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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://zajinet.ru/strik?utm_term=what+does+4+beeps+mean+on+a+mercury+optimax PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4415930/normal_6041476720605.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4473903/normal_6061dc9745155.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413008/normal_60442415f1c4b.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4392871/normal_5fe20632b8afa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4459929/normal_5fde33767a0e5.pdfIn PDF document text
    • http://ruwemipuwev.mypressonline.com/quran_arabic_english_transliteration.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417403/normal_60301e7f7c39c.pdfIn PDF document text
    • http://vopugixeroramox.medianewsonline.com/7_canciones_populares_espaolas.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4469101/normal_600ae3d62c9ed.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/0e40833a-aa48-425d-bcfa-7d3cc9e5785e/questions_to_ask_married_couples_about_their_relationship.pdfIn PDF document text
    • https://36071b1a-d853-4ad1-bccf-0ed894d94038.filesusr.com/ugd/906e9f_68ad26c54ee64ec08e889927d37efe21.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/a45371fe-a334-44cc-8727-8d133c406aa0/harriet_tubman_biography_book.pdfIn PDF document text
    • https://eed7fa7e-4f31-4ba6-8269-e73f07ac74c5.filesusr.com/ugd/93374d_e0408f7f389e48eaa25978cb338f3fe3.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/433de481-8381-4251-b1a1-6339f9b3edc3/the_crucible_act_3_study_questions.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/86675eb3-f160-4344-8932-3fcdbcc12943/datatodupinojojewapun.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/dd3d832e-7c52-43b3-988c-475a6361c987/24725492287.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1bef610d-04ee-4ac3-9b15-1f6774366459/super_mario_3d_land_3ds_rom_download.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/210e3910-5fde-4064-8c1f-bdde0356edaf/ximevezukume.pdfIn PDF document text
    • https://2559d30b-64cd-4b4d-aaad-e76a675dde99.filesusr.com/ugd/f5a024_16397734b3794927bea2b62c837b72e6.pdf?index=trueIn 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_off0000fe8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE8A 5692 bytes
SHA-256: f4d8e52c413db0c2be9cf201b7a515fbe80cfb30f6578208fc7fc24261f29eda
font_01_sfnt_off000111d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111D5 10960 bytes
SHA-256: 2040ff3c45e1e80ebb70533c6cc353211312275049cea377a40d040b9c48bbc7