Malicious PDF — malware analysis report

Static analysis result for SHA-256 edf79c36d8931a34…

MALICIOUS

PDF

68.2 KB Created: 2021-03-09 18:53:01 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: bcdc27b3a244b699711fcfdb3cdffbdc SHA-1: a23dc215000c2db82bc3881ba5131ad727340bca SHA-256: edf79c36d8931a349cd1e5f34d250e188dfb7190720dde7dcfaa0634c446952f
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains a large number of external links, identified by the PDF_SEO_LINK_FARM and PDF_SEO_DISPOSABLE_LINK_FARM heuristics. The primary URL observed, https://jacksth.ru/award?keyword=english+crossword+puzzles+with+answers+for+class+3+pdf, suggests a lure related to educational content, likely to disguise malicious intent. The ML classifier and ClamAV detection strongly indicate maliciousness, consistent with a phishing or SEO spam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://jacksth.ru/award?keyword=english+crossword+puzzles+with+answers+for+class+3+pdf PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4416500/normal_6002d5afd63b0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4477147/normal_5fd665a4a4195.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4485696/normal_6016389618cdc.pdfIn PDF document text
    • https://rizogedimawe.weebly.com/uploads/1/3/0/7/130739598/fabakuso.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366010/normal_5fd9485aa1a8a.pdfIn PDF document text
    • https://cdn.sqhk.co/xewimoziwuvo/gfkidgh/saliwo.pdfIn PDF document text
    • https://cdn.sqhk.co/nebuneduzib/1hehcoU/sifexovixexuvaga.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4461249/normal_60296ca8d936d.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485930/normal_5ff494e785856.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4384655/normal_600eca62a4f27.pdfIn PDF document text
    • https://cdn.sqhk.co/mofinopedas/hgZhigf/ripodomipizojodalazomitin.pdfIn PDF document text
    • https://cdn.sqhk.co/zorezikuluz/ghfhdhf/jonarudebanivewukonureb.pdfIn PDF document text
    • https://kevulukopefot.weebly.com/uploads/1/3/1/4/131453006/xuxinimuwagaw.pdfIn PDF document text
    • https://gitakitopawal.weebly.com/uploads/1/3/5/3/135325500/1847836.pdfIn PDF document text
    • https://cdn.sqhk.co/jotenitix/jdiadA0/sunday_school_lessons_for_adults_2020.pdfIn PDF document text
    • https://regagilozot.weebly.com/uploads/1/3/1/8/131871395/3249199.pdfIn PDF document text
    • https://mefiremen.weebly.com/uploads/1/3/0/7/130776246/2131646.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/9608d94d-e404-4a3b-9004-734801b1e940/danby_kegerator_instruction_manual.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a05b321d-566e-47e4-86c8-b6195dfb5e11/72995956234.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/9ed0e710-2c3d-4f68-8852-7a7c0e38a6f9/fight_club_workout_crossfit.pdfIn PDF document text
    • https://dae57379-2785-4108-a223-4562ecbfc22e.filesusr.com/ugd/87ad98_9bf09a8c750a4c92b768d077f8f0c8a7.pdf?index=trueIn PDF document text
    • https://1094d5c0-a920-47c7-a1de-7e2d56a92d84.filesusr.com/ugd/47b1e8_4be3934b93ac4f499884442ccb432cb9.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_off0000cdbb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDBB 5680 bytes
SHA-256: 823aaba604e38e5b48cbc015e2bca19c30ea3cef62a9e905e9650ec40ed58ddf
font_01_sfnt_off0000e133.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE133 9964 bytes
SHA-256: 60a9054533e7aacb17c1660d1740b4d85c50dc99209dddf8d0804a82d89051ba