Malicious PDF — malware analysis report

Static analysis result for SHA-256 186ac7ba5b490a23…

MALICIOUS

PDF

98.9 KB Created: 2021-03-23 07:52:30 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-17
MD5: c73e600d1d94109ff6867c25c8abee04 SHA-1: 49618d944f27de77f6d4877cf6fe729a948d4819 SHA-256: 186ac7ba5b490a238d5716daea3624b882ad6b0a5de5951a46ab1c4f75f2a9b8
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to disposable hosting, suggesting a link farm or phishing operation. The ClamAV detection and ML classifier strongly indicate malicious intent, specifically identified as Pdf.Phishing.Trojan. While no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a phishing or malicious redirection campaign. The primary URL, https://kuzutuzo.ru/strik?utm_term=mental+status+examination, is likely the initial lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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://kuzutuzo.ru/strik?utm_term=mental+status+examination PDF link annotation
    • http://xejiwov.iblogger.org/maintenance_technician_resume.pdfIn PDF document text
    • https://rogefuza.weebly.com/uploads/1/3/4/6/134688393/165843.pdfIn PDF document text
    • https://damabinon.weebly.com/uploads/1/3/0/7/130738970/nabijadexas.pdfIn PDF document text
    • https://nipezititixi.weebly.com/uploads/1/3/4/6/134688951/denunutinit_famonidepirugul.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://a694a867-b0fa-45cd-b082-7f9abf80b1a7.filesusr.com/ugd/430cb2_a210e9a204194cc9ba3b9c38c6d937b1.pdf?index=trueIn PDF document text
    • https://d64d5b41-a66a-4b78-b87f-0feaf8e9cf76.filesusr.com/ugd/cf1aed_7b542fa035704329b7f89cbb7671f3e3.pdf?index=trueIn PDF document text
    • https://77047a80-9f17-4504-a563-a097c25ca12e.filesusr.com/ugd/5c8b2f_64a0569587224148b26b48da183a32e4.pdf?index=trueIn PDF document text
    • https://49b821e7-ee7e-41b4-809b-d0417b8c1ddf.filesusr.com/ugd/927743_157956058c71412fb541fd9a826f9798.pdf?index=trueIn PDF document text
    • https://6d8b2927-5c4d-40df-b593-c6bd35e19528.filesusr.com/ugd/1adac8_8772727e699f4e5daf0aa99aa8205b0e.pdf?index=trueIn PDF document text
    • http://jegusimiluf.epizy.com/ammonium_sulphate_precipitation_chart.pdfIn PDF document text
    • https://b4e79a3f-0083-4b26-8056-4fe87fb46dfd.filesusr.com/ugd/332c1b_d2a84d80703b4db1a542e840a8dbbd27.pdf?index=trueIn PDF document text
    • https://089130c0-62ae-4bf1-a93c-656440fe8451.filesusr.com/ugd/738632_31cb0f9c86c44c288f3121b5c346947b.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/5a41088f-4fc6-44a9-8192-c56357fbb996/ross_carbonite_black_solo_frame.pdfIn PDF document text
    • https://128fc002-9ed4-4a8f-9a6b-83b43563a9ed.filesusr.com/ugd/6812d7_7e0ae6e52dea43568a4bba1348634497.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/382754b8-5ffc-4c61-97a5-e5a75e515ac7/how_to_calculate_interest_payment_on_loan.pdfIn PDF document text
    • https://769966b8-4adc-437e-bba8-f198cf6e171b.filesusr.com/ugd/41a0b6_a27454bdbe6c4aa8bddf71a8b9e9a495.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/5d14c515-5820-49e8-8417-f138c995cf4a/where_can_i_buy_rheem_furnace_parts.pdfIn PDF document text
    • https://6c036dbd-b327-4678-b778-de8a2ee7bb50.filesusr.com/ugd/ed64d2_d29bf7a3684b4c0eabb66b2140720623.pdf?index=trueIn PDF document text
    • https://f45985d3-969e-4a4b-a16b-f92b7c881388.filesusr.com/ugd/20da2d_cc89fb111cf4471d879f41d56a45c0f1.pdf?index=trueIn PDF document text
    • http://bibubojudij.rf.gd/how_to_remote_start_car_with_viper.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_off0001477e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1477E 4808 bytes
SHA-256: ec4bc3b4deabd32e9c8c43432aebae623c5655ce6df84b257e56ed5d1c135eb9
font_01_sfnt_off000157d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x157D7 11660 bytes
SHA-256: b1ed6b862731d41ef3b5732dfee079fd12c8f8a2cce71c914a3693e08670119e

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