Malicious PDF — malware analysis report

Static analysis result for SHA-256 57ea85a743828343…

MALICIOUS

PDF

50.3 KB Created: 2020-11-08 09:10:52 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-15
MD5: ef74c0ce52dedbc458c5503e7bd0435f SHA-1: 7ce3b211ec23f626caef364ef5504b19879d0505 SHA-256: 57ea85a7438283435abe8fe2a91440a91112a603ca77b4d81e3f042eeda39853
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file contains a large number of external links, many of which point to disposable hosting and appear to be part of an SEO link farm. The primary embedded URL, https://traffnew.ru/123?keyword=printable+skeletal+system+diagram+pdf, suggests a lure to attract users interested in skeletal system diagrams. While no scripts were explicitly extracted, the PDF structure and the heuristic firings indicate malicious intent, likely related to SEO manipulation or redirecting users to potentially harmful content. The ML classifier strongly supports the malicious verdict.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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://traffnew.ru/123?keyword=printable+skeletal+system+diagram+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4382186/normal_5f8ca369d4e30.pdfIn PDF document text
    • https://megadezatesaram.weebly.com/uploads/1/3/0/7/130776649/1462530.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://poxijotavix.files.wordpress.com/2020/11/all_clad_replacement_parts.pdfIn PDF document text
    • https://sumifomigat.files.wordpress.com/2020/11/11815544020.pdfIn PDF document text
    • https://s3.amazonaws.com/kudefem/2006_cadillac_srx_repair_manual.pdfIn PDF document text
    • https://livilixojef.files.wordpress.com/2020/11/jirinemupikivabazijefel.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/59c082c7-cc27-43c0-a0a7-ec583d66242d/rijojazededegasonodud.pdfIn PDF document text
    • https://zogidadovo.files.wordpress.com/2020/11/gepixizorekabonagasi.pdfIn PDF document text
    • https://s3.amazonaws.com/jazofi/4141373977.pdfIn PDF document text
    • https://gumomonixita.files.wordpress.com/2020/11/hoja_con_lineas_para_escribir_una_carta.pdfIn PDF document text
    • https://bepamikolif.files.wordpress.com/2020/11/tusuwekagosimixo.pdfIn PDF document text
    • https://fudogajul.files.wordpress.com/2020/11/gatejofa.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fa3ebdd6-b32a-45e7-aca5-cf37604b951b/39009676878.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_off0000849a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x849A 5668 bytes
SHA-256: 6c27beb117820d42c07e7ec8a036a3f9ed0564989f5046e4567194078175cd72
font_01_sfnt_off000097d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x97D5 10760 bytes
SHA-256: f64b6a81d004d9403cabaabfcf8db486f3919d4863d91eed7d443763fa877e52

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