Malicious PDF — malware analysis report

Static analysis result for SHA-256 5892f1a9ea6ccac3…

MALICIOUS

PDF

81.9 KB Created: 2021-05-19 08:47:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 1106927bf06ed16079298455d718bfee SHA-1: 71d8ed59c3d78909a8fa7e79167becf62d77fd59 SHA-256: 5892f1a9ea6ccac36ff9882c2fb68551e892116d3b67299503b8b586367d93ad
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many pointing to disposable hosting services, and uses a lure of an 'English placement test'. This behavior is indicative of a link farm or phishing campaign designed to redirect users to malicious or ad-fraudulent websites. The ClamAV detection and ML classifier strongly support its malicious nature. Although no scripts were explicitly extracted, the PDF structure and embedded URLs suggest it's designed to facilitate initial access via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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=english+placement+test+pdf+beginner PDF link annotation
    • https://topigofifudonif.weebly.com/uploads/1/3/5/3/135304546/jovojofopiw.pdfIn PDF document text
    • https://nitomono.weebly.com/uploads/1/3/1/4/131454496/3981217.pdfIn PDF document text
    • https://bubigijezifaju.weebly.com/uploads/1/3/1/3/131380429/mosunibefupijepisa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4411479/normal_5ffbd8a92576c.pdfIn PDF document text
    • https://zoseduzarososu.weebly.com/uploads/1/3/2/7/132740870/29e93458643f62.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4450038/normal_6020a0a049871.pdfIn PDF document text
    • https://gubagomokugexat.weebly.com/uploads/1/3/3/9/133988684/zazapipupenozan.pdfIn PDF document text
    • http://vudujupuboneg.22web.org/badogiposu.pdfIn PDF document text
    • https://wipomozexabezi.weebly.com/uploads/1/3/0/7/130776841/dafd924d872aa.pdfIn PDF document text
    • https://budoxaku.weebly.com/uploads/1/3/0/8/130873914/kituxilofod.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4455376/normal_6004fc67e9a8e.pdfIn PDF document text
    • http://wijotit.iblogger.org/26010116350.pdfIn PDF document text
    • https://rudarizegofuk.weebly.com/uploads/1/3/4/3/134355262/459791.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/d264b5f3-ae88-4972-a551-d28e53c4d9b3/jepegararase.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4999f24e-466c-4976-8461-4da3d5850b0c/zotowulu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/636f1c85-ada2-42e0-b54c-2af59d5b9586/hp_deskjet_6540_ink_levels.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7df84abe-8934-4b4a-b4c3-f6a500b834e3/the_book_thief_download_epub.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/071d6473-3850-4906-8411-ae86a67058ef/can_you_get_fallout_new_vegas_dlc_on_xbox_one.pdfIn PDF document text
    • http://sufumawug.epizy.com/didifebexoxekalorekese.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8c9fc600-d033-4cd5-940b-27da26b280e1/72752153971.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/250b2291-7b26-47c4-967a-c346f0cd8261/nikorosolotedu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/26ad9b26-3c22-4627-aa9a-c3469f5b26d3/sutewugenuzowe.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ed479e6e-33a2-4b95-833a-c070a3ae925f/luxumagenebunitadile.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_off0000fe96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE96 5668 bytes
SHA-256: 81520a24429d05ce1b05d090b06ec66e6a6c73d0e501bb1a7cd273cbc1ae8da1
font_01_sfnt_off000111b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111B2 11492 bytes
SHA-256: 7b07293ec12cf97f25354d6e12c21e6e88d254ac9caa64151a6fc4a23fe679ca