Malicious PDF — malware analysis report

Static analysis result for SHA-256 c791f88dfa038ea1…

MALICIOUS

PDF

77.6 KB Created: 2021-09-17 14:00:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 7e41d08deff4e86823f8b72fc2c71796 SHA-1: 4f0fef1a5b16ab089a5a88f54ae5528b5a5e0653 SHA-256: c791f88dfa038ea1159b22aa347b491473450820b0250925a49a889b0ca764a0
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains embedded JavaScript and numerous URLs, many of which point to compromised or disposable hosting, suggesting it's part of a link farm designed to redirect users to malicious content. The embedded JavaScript likely facilitates the execution of further malicious actions or redirects.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://krisoc.ru/uplcv?utm_term=introduction+to+algorithms+cormen+ppt+slides PDF link annotation
    • https://mobilaide.com/upload/editor/file/varivuzugugejijifij.pdfIn PDF document text
    • http://zima.italie-ubytovani.cz/data/file/demutuvap.pdfIn PDF document text
    • http://shopabrang.com/images/files/nevixaxixolur.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613d670ef0ca6---sokovuvugakasuw.pdfIn PDF document text
    • http://bancasemecanino.com/userfiles/files/xafetove.pdfIn PDF document text
    • https://sieuthimaytinhcu.vn/upload/files/nemapulozebu.pdfIn PDF document text
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/7e095e677f9bb7b26caa080daf066133/nitofixefesebivutolikin.pdfIn PDF document text
    • http://stroykap.com/application/views/stroykap/userfiles/file/polaxulotagolifurexexujor.pdfIn PDF document text
    • http://gemwishrs.com/ckfinder/stones/files/87942754190.pdfIn PDF document text
    • https://vico-real-estate.com/ckfinder/userfiles/files/22012208042.pdfIn PDF document text
    • http://thehedgerowchronicles.com/ckfinder/userfiles/files/xatuxikudedenojiz.pdfIn PDF document text
    • http://www.adarshvidhyasankul.org/userfilesfile/29151737983.pdfIn PDF document text
    • https://wisserarm.nl/app/webroot/files/userfiles/files/weruvimon.pdfIn PDF document text
    • http://joltiy.ru/uploads/files/pusawubozezetir.pdfIn PDF document text
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161404842811ba---2413099552.pdfIn PDF document text
    • https://landi-bg.com/images/file/31148725397.pdfIn PDF document text
    • http://www.mariabeckmann.com/fotos/uploads/files/49741331440.pdfIn PDF document text
    • https://www.cosanuesa.com/componentes/editor/ckfinder/userfiles/files/doxom.pdfIn PDF document text
    • http://docando.es/js/ckfinder/userfiles/files/54217605468.pdfIn PDF document text
    • http://terhautz.com/upload_files/files/pebapefokajojazefodaboda.pdfIn PDF document text
    • http://villaturri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613239ec2aef8---sopop.pdfIn PDF document text
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/a752452d60f3bd0326f0e8d6e11e7f6d/12534788355.pdfIn PDF document text
    • http://aldo-ins.com/userfiles/file/45193193371.pdfIn PDF document text
    • https://mobile-translator.eu/app/webroot/media/files/vuwerogurarafuxipegudi.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://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_off0000c888.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC888 18096 bytes
SHA-256: db65a06a87c27c101e57861467a417616167fa02f18ae6a786724d1b3eb21c46
font_01_sfnt_off0000f706.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF706 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010f1d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F1D 11012 bytes
SHA-256: dfd553229048b2206b61a6fb8927176a1b327ac6db6a7ee4e2e87c97745b8f80

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