Malicious PDF — malware analysis report

Static analysis result for SHA-256 c0156e2db4a81d43…

MALICIOUS

PDF

72.5 KB Created: 2021-09-08 23:17:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 43161d026382e26d2de7c8f4ed79e0d2 SHA-1: 91487a548efd87d62cda8e87ff57ea1e88240d88 SHA-256: c0156e2db4a81d43b18febb28b0f90553339b8d8dbb654be463bf91818fd1eb1
166 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan. It contains numerous links to external PDFs hosted on various domains, many of which appear to be disposable. One high-severity heuristic specifically identifies a PDF link to an algorithmically-generated URL, suggesting a phishing or malware distribution attempt. The ML classifier also strongly indicates maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://vieclamlaocai.vn/webroot/img/files/vuvalanodaruzakopamixujev.pdf In PDF document text
    • http://hillsdalehorseboarding.com/ckfinder/userfiles/files/fipikevexego.pdfIn PDF document text
    • http://bienbao.org/uploads/files/17219668535.pdfIn PDF document text
    • https://u15.ch/ckfinder/userfiles/files/gozupifede.pdfIn PDF document text
    • http://originalbau.hu/imagesfiles/kuzakewanipoz.pdfIn PDF document text
    • http://ark-mr.com/data/home/qxu2063190031/htdocs/uploadfile/files/punude.pdfIn PDF document text
    • http://ewtch.com/upload/files/mufiwutaroxa.pdfIn PDF document text
    • https://koltoztetes-szallitas-lomtalanitas.excore.hu/ckfinder/userfiles/files/divavozefoludoxusasavepew.pdfIn PDF document text
    • https://flomogroup.com/upload/files/jajezofefo.pdfIn PDF document text
    • http://sanxuatbanthinghiem.org/app/webroot/uploads/files/72067541273.pdfIn PDF document text
    • http://alexlunacoach.com/img/editor/file/31657567457.pdfIn PDF document text
    • https://samngaimarble.com/html_upload/file/748635664.pdfIn PDF document text
    • https://cissud.it/uploads/ck_editor/files/53201536381.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/3ee063b8afe526ce5be68524c2f316a4/36561069087.pdfIn PDF document text
    • https://www.mobytec.com.br/mobytec/wp-content/plugins/formcraft/file-upload/server/content/files/16136140424542---tarowoxudoruji.pdfIn PDF document text
    • http://studiomedicoveterinariobellucci.eu/userfiles/files/wopiwefakogajimuw.pdfIn PDF document text
    • http://market-oborudovanie.ru/upload/file/30441596237.pdfIn PDF document text
    • http://utcsp2.rustyramone.com/uploads/files/45473439863.pdfIn PDF document text
    • https://unovosti.tv/ckfinder/userfiles/files/94292180720.pdfIn PDF document text
    • http://hkwwta.org/userfiles/74001722826.pdfIn PDF document text
    • http://gidaero.com/upload/fckeditor/file/31662414665.pdfIn PDF document text
    • http://bibrka-school.org.ua/ckfinder/userfiles/files/43171841779.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/fapadudemeraroninomani.pdfIn PDF document text
    • http://rcot.by/pics/files/kujoxire.pdfIn PDF document text
    • http://marinaxaraes.com.br/ckfinder/userfiles/files/todafaperomukexotovumolew.pdfIn PDF document text
    • http://elitakhealing.com/ckfinder/userfiles/files/dasodumezeleted.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=compress+picture+size+androidPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ba0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBA0D 10820 bytes
SHA-256: 683c90a42323cd7599d826920e61a5ec0cd2e61dde86d952c9bb0536f6f8a1a4
font_01_sfnt_off0000d310.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD310 16068 bytes
SHA-256: 5b3eacf18ed58543adff3e0ee240fbbd527ff031392cf16fae2057a8a5b36110
font_02_sfnt_off0000fc50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC50 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1