Malicious PDF — malware analysis report

Static analysis result for SHA-256 b141e6c98db16dd8…

MALICIOUS

PDF

81.9 KB Created: 2021-09-17 15:23:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: b8c83105e4f392e625405c6e9f230ba3 SHA-1: e180ef264210209389d7ef40d6f814a6fbb6bf07 SHA-256: b141e6c98db16dd89fc17f448b5bb1f5b1d3ee3af19d12e45d37f7c12553ece0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics indicate the PDF functions as a link farm, directing users to multiple external websites, some hosted on potentially compromised CMS platforms. The document body is heavily obfuscated and unreadable, suggesting an attempt to hide its true purpose, which is likely to lead users to phishing or malware download sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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
  • 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.
  • 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://toptenstudy.com/upload/files/BodyFile__61374DF3CE4A5.pdf In PDF document text
    • https://strategie-forex.com/ckfinder/userfiles/files/9453396300.pdfIn PDF document text
    • http://mudrberanova.cz/userfiles/file/kabikejaxozivo.pdfIn PDF document text
    • http://tiyuchangdi.com/upload_files/files/20210917_021703.pdfIn PDF document text
    • http://china-miyaco.com/img/file/20219242122.pdfIn PDF document text
    • https://shiksha24.com/userfiles/files/56611531857.pdfIn PDF document text
    • https://stalbeckers.nl/userfiles/image/file/renijumuxikazafuk.pdfIn PDF document text
    • http://origo.ws/userfiles/file/47844378007.pdfIn PDF document text
    • https://tipresentoio.it/images/file/busugetalo.pdfIn PDF document text
    • http://secondhandgraphics.com/usrfiles/file/zuzubagorifi.pdfIn PDF document text
    • http://impex-italia.it/userfiles/files/3934813358.pdfIn PDF document text
    • http://www.civilhospitalpalampur.in/img/uploads/files/3616292528.pdfIn PDF document text
    • https://ladulceseguros.ar/noticias/fckeditor/file/45942948782.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/16144137620dd3---95501407642.pdfIn PDF document text
    • http://immodraft.nrw/images/architekten_agentur_images_/file/buwomimagodutuwasebebiru.pdfIn PDF document text
    • https://sistemagestiondpr.co/userfiles/file/raravune.pdfIn PDF document text
    • https://labelmarket.eu/data/file/jeliliwarudipoja.pdfIn PDF document text
    • https://www.vibrationmonitoring.asia/wp-content/plugins/formcraft/file-upload/server/content/files/16141762f657ef---12385825375.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/2l06c5iut5159mqjb863gf0s2v/5046345472.pdfIn PDF document text
    • http://zrdb-drogbud.pl/Upload/file/3142627350.pdfIn PDF document text
    • http://lingeriedediva.com/UploadFile/file/2021091415154273499.pdfIn PDF document text
    • https://diversifiedhumansolutions.com/wp-content/plugins/super-forms/uploads/php/files/cdca56155e40a06972eb1d67e7c8bd5e/tupijapitumoserujuzati.pdfIn PDF document text
    • http://cameradungphat.com/uploads/files/runiforitakikajujoz.pdfIn PDF document text
    • http://mineraux-et-lithotherapie.fr/ckeditor/upload/files/51529257675.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=android+tv+oreo+x86+isoPDF 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_off0000d836.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD836 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f048.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF048 18972 bytes
SHA-256: 16bcf36df073f9d49e529d87d4b9c00e4cf6857654ee5f4caf13220bbfdd9aaf
font_02_sfnt_off000121ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121ED 10556 bytes
SHA-256: 647b146e210c8dbdea09622de4362b3e89b46962a84cf712b63daa28ec1ba914