Malicious PDF — malware analysis report

Static analysis result for SHA-256 9973c5af46d8bc2a…

MALICIOUS

PDF

79.7 KB Created: 2021-04-26 05:54:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 4fccc0078652efcd85c19228ea6c310c SHA-1: a34d50f96bfe1753b5bb24ca84dbbc4daaf424ad SHA-256: 9973c5af46d8bc2a3b101b1d8234fe029b33aa83cf255ab0539d39c6d0de48e9
126 Risk Score

Malware Insights

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

The PDF document contains numerous embedded URLs, many of which point to disposable domains and are likely part of a link farm designed to obscure the final malicious destination. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically phishing. The document body, though heavily obfuscated, suggests a lure related to a book download, which aligns with the PDF_SEO_DISPOSABLE_LINK_FARM heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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/strik?utm_term=dork+diaries+13+read+online+free+full+book+pdf PDF link annotation
    • http://constructionhouse.info/301436918579gja8.pdfIn PDF document text
    • http://autolombardpro.ru/85457475602psf5o.pdfIn PDF document text
    • http://frukt.space/33911608170jv3ik.pdfIn PDF document text
    • http://lerob.info/zizowotenojeldl70g.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4422378/normal_60278a4f094d7.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4378619/normal_5ff94233e5169.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4477156/normal_5fdbd078c939d.pdfIn PDF document text
    • http://bestpriceforukraine.xyz/pavotasetln57.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369306/normal_5fd82dce0c1fb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4474722/normal_601e5a44090c5.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4424025/normal_5ffb4b2a1ee13.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485442/normal_5fc7d377d4b76.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4463554/normal_60152132dfe1a.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/telasebisu/47942573691.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c2c41c85-5a77-4dde-b78f-7bb44f6a257c/how_old_is_2008_birthday.pdfIn PDF document text
    • https://s3.amazonaws.com/xeroguru/58381207066.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a09f03d8-be45-40b9-9b47-5f65acaef556/54532885207.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/403d20eb-2b48-47a5-8847-519137c0d6b9/spanish_b_for_the_ib_diploma_textbook_answers.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0c38e043-d6f3-4850-9d3e-a4ccf874b842/63944360548.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cc82ff36-c7b1-4e94-b047-e4239083e06a/75616307990.pdfIn PDF document text
    • https://s3.amazonaws.com/xezonijida/adding_and_subtracting_integers_worksheet_puzzle.pdfIn PDF document text
    • https://s3.amazonaws.com/xefezesebusu/vaziboveberetomozito.pdfIn PDF document text
    • https://s3.amazonaws.com/pazatuv/fajezenabovi.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/babcc9ca-6989-4f45-96cd-c7a20af641d0/what_does_rational_religion_mean_in_nursing.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_off0000fa82.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA82 5452 bytes
SHA-256: 52b1553bf615862a0a228fe65eaf5eafe3aa8ea0e34ccf0173ef95ef97aa381d
font_01_sfnt_off00010d23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D23 10540 bytes
SHA-256: a80292e2b97974e5e5b1abedd1eca09209522788de3df213d869cfc6c5ad9686