Malicious PDF — malware analysis report

Static analysis result for SHA-256 798460e57c7ac709…

MALICIOUS

PDF

68.2 KB Created: 2021-01-28 22:51:48 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: ffe443d40e2e030931077d153aa7ef49 SHA-1: c8b7ae0e729895fa79b822a22fab26b456b3856a SHA-256: 798460e57c7ac709ffa5e5ef3872930bdf842887efb0e9bc14cdc94acbece548
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier indicating maliciousness. It contains numerous embedded URLs, with at least one, 'https://crophysi.ru/123?utm_term=gustar+worksheet+pdf', identified as an external URI and part of a link farm on disposable hosting. While no scripts were explicitly extracted, the PDF structure and the nature of the URLs suggest an attempt to redirect the user to a malicious site, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://crophysi.ru/123?utm_term=gustar+worksheet+pdf PDF link annotation
    • http://xosukesodur.22web.org/18325784263.pdfIn PDF document text
    • https://vigajinid.weebly.com/uploads/1/3/4/8/134889024/bomivodefiz.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496389/normal_6010a228b38f2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4448984/normal_600dffe6d20dd.pdfIn PDF document text
    • https://bolefusugo.weebly.com/uploads/1/3/4/8/134868203/rukukiz.pdfIn PDF document text
    • http://feelslike35.com/34864020925ddefm.pdfIn PDF document text
    • https://tiwudusakuwizir.weebly.com/uploads/1/3/1/6/131637104/3855124.pdfIn PDF document text
    • https://cdn.sqhk.co/jimumakevaji/N3iegdc/fishing_hook_knots_tool.pdfIn PDF document text
    • https://valuluxunu.weebly.com/uploads/1/3/2/7/132710491/jagemud.pdfIn PDF document text
    • http://circus.market/shimano_acera_front_derailleur_instructions5uxfc.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421478/normal_600fda929a70d.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/gedesisumi/93221833457.pdfIn PDF document text
    • http://bopuxenuxesozu.rf.gd/83756929716.pdfIn PDF document text
    • https://s3.amazonaws.com/tujeviwakirawu/riferokidovoj.pdfIn PDF document text
    • http://vulomalizekuvu.rf.gd/inventory_management_in_excel_sheet.pdfIn PDF document text
    • http://jiresigotapikeb.rf.gd/89912882046.pdfIn PDF document text
    • http://dowijasimenazo.epizy.com/80733993615.pdfIn PDF document text
    • https://s3.amazonaws.com/polexebuj/23507633915.pdfIn PDF document text
    • https://s3.amazonaws.com/dobikasukavu/spring_framework_reference_documentation_3._2.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_off0000cb84.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB84 5284 bytes
SHA-256: f8384e3e1d1eefab1977fd9558533fc2f7755e038bd7325512923b5fb5694179
font_01_sfnt_off0000dd92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD92 11876 bytes
SHA-256: 11d0a691f836e357d045f47e4ed62a763c6e3f4d659f0263d9b8d2d24d426f5b

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