Malicious PDF — malware analysis report

Static analysis result for SHA-256 a41fde1aae7bf167…

MALICIOUS

PDF

73.6 KB Created: 2021-06-10 09:38:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: ecdf861074c6521dc8b26fc658c4ad7a SHA-1: d91bdb07d30e66a2588111ea0107444b9da88bea SHA-256: a41fde1aae7bf1677a7103a4bf5338f437b1dadaa77060cbc76e9fcd0302f043
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains numerous embedded URLs, with a high-confidence ML classifier and ClamAV detection indicating malicious intent. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests a tactic to obscure malicious links within a larger set of redirects. The primary malicious URL identified is https://synerhu.ru/pbw?utm_term=best+cars+in+hill+climb+racing, which is likely used to deliver a secondary payload or conduct phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://synerhu.ru/pbw?utm_term=best+cars+in+hill+climb+racing PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4527164/normal_5fed348bde1bb.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4377679/normal_5fe2d37692fa0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4383304/normal_604222c441c71.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://gepefupugalu.pbworks.com/f/cl_activation_windows_10_famille.pdfIn PDF document text
    • http://jebodigezev.pbworks.com/f/adverb_worksheets_grade_6.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6c57ef25-1106-49c7-9b00-1f868d0a2642/best_voice_recorder_for_pc_free_download.pdfIn PDF document text
    • http://zezupagijene.pbworks.com/w/file/fetch/144602124/govosozuveridosor.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a211dbec-29a7-4719-9cab-4b1ad13a9954/palapulexuxurik.pdfIn PDF document text
    • http://ziludezubeju.pbworks.com/w/file/fetch/144464049/pizapurotemoviraguvobefij.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/345adc2f-9a09-4f9b-bde2-9344e547f399/half_life_2_raising_the_bar.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1cdf3c21-3482-46d6-a7c4-7ade311e18c1/64816443769.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/eec62840-3482-47ee-8133-ff27f965ab1e/how_to_use_voicemail_on_vtech_home_phone.pdfIn PDF document text
    • http://redelaw.pbworks.com/w/file/fetch/144658572/nefejexutamozewefedebubi.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7dc3fb21-92c4-4926-89bd-e2e1a515dd1b/22837829756.pdfIn PDF document text
    • http://sajutom.pbworks.com/f/feduvurimuvifanuzugagemed.pdfIn PDF document text
    • http://xojipoxar.pbworks.com/f/84367276950.pdfIn PDF document text
    • http://risodige.pbworks.com/f/49732600159.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b5da7474-2d4a-48fc-8277-6b13c92b0ea0/jofotijoket.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d4e5037a-be69-4289-8031-e8ae227a5992/swiffer_wet_jet_not_spraying.pdfIn PDF document text
    • http://finebov.pbworks.com/f/fasitubusi.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_off0000e140.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE140 5400 bytes
SHA-256: 0854f9d7e9224f3df2fc40d5c4bf270bf84d4e8a03a630527438a71ab9e927d0
font_01_sfnt_off0000f37a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF37A 10648 bytes
SHA-256: eec67c3f537e8f53f32879d8d236fe0f18cda77db7e9daf6ed228ea9fb1cc84a

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