Malicious PDF — malware analysis report

Static analysis result for SHA-256 6235030f4018f52b…

MALICIOUS

PDF

78.3 KB Created: 2021-05-28 03:18:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 760707b7cdd2e5a812387f7cf0d416f4 SHA-1: 26a3f043ecfac36d16ed096901d68d3a075f24aa SHA-256: 6235030f4018f52ba838b30e8b867f8b773b31630f9e234661924c92465ce38e
186 Risk Score

Malware Insights

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

The PDF file contains numerous external links, many of which point to a link farm designed to host other PDF documents. The primary lure appears to be a deceptive offer for free Spanish chess books, which redirects to a page with a high density of links. This behavior is indicative of a phishing or SEO poisoning campaign, likely aiming to drive traffic to malicious or spam content. The ML classifier and ClamAV detection strongly support the malicious verdict.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://leonvi.ru/strik?utm_term=libros+de+ajedrez+en+espa%25C3%25B1ol+pdf+gratis+sin+registrarse PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4410432/normal_6012b787a5136.pdfIn PDF document text
    • https://mosatidopo.weebly.com/uploads/1/3/4/7/134731439/25203.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4456985/normal_60470a58852a9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369788/normal_60299f1db52f3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4412195/normal_5fdaff8c4fc5f.pdfIn PDF document text
    • https://jozokuxig.weebly.com/uploads/1/3/2/8/132814463/2650450.pdfIn PDF document text
    • https://nudaduxovusupin.weebly.com/uploads/1/3/4/3/134337963/gapufirewav_fataz_defipiwipir.pdfIn PDF document text
    • https://gavufiwi.weebly.com/uploads/1/3/0/7/130775220/64ef4.pdfIn PDF document text
    • https://mekozatopuwuju.weebly.com/uploads/1/3/4/5/134512494/doxijojepifod-gunizonegekozoz-nezorofa-xoxafunaworog.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4374835/normal_60041aaa1d9bb.pdfIn PDF document text
    • https://zizopozuwugova.weebly.com/uploads/1/3/0/7/130775786/d6e9a742e337465.pdfIn PDF document text
    • https://zukusabaxiwig.weebly.com/uploads/1/3/4/0/134000387/xagito.pdfIn PDF document text
    • https://sosedegif.weebly.com/uploads/1/3/2/8/132815053/tigafolesigano-gumovovowib-dukamabobukiti.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4486566/normal_5fcc61e77e3be.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4470205/normal_5fe41d02bcfb7.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/93472919-9f70-48ef-8b40-7a61699e6750/epson_v850_vs_v600.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/2c929190-a1d4-414c-95ab-9eebea377dbc/80138472005.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/24260e9f-a7a1-4d97-8a06-9b755192beb5/vba_excel_to_converter.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6f512610-dc91-4276-bde3-7c9281db3951/brother_6490cw_wireless_setup.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d2f15118-acfa-412d-ba8b-ffca75393ad7/visual_basic_greyed_out_in_excel_2016.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_off0000f20f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF20F 5628 bytes
SHA-256: 4f59bee60e432196ca9479f116855b6a3f4068de226de210105e9754ac24d470
font_01_sfnt_off0001050c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1050C 11064 bytes
SHA-256: 040614f57b84acf6a50dd7430f61b19c17c695848905cf61dbe16b1f9c68128d