Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4fd73a391963060…

MALICIOUS

PDF

73.0 KB Created: 2021-09-26 23:36:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 94b541254b285ddf75b3574c2c8d7bf5 SHA-1: 63b8a3b7b3c2188aeb0c9b733d5fc9438bc34504 SHA-256: a4fd73a391963060d0a33684ec86f7234eb1aed4cb82b1a95543ae021d543064
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, indicating the PDF's primary function is to act as a lure or redirector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://laborke.ru/uplcv?utm_term=walking+dead+premiere+season+11 PDF link annotation
    • http://greenld.com/userfiles/65875574722.pdfIn PDF document text
    • http://modero.vn/upload/files/67122584005.pdfIn PDF document text
    • https://loan-financial.com/wp-content/plugins/super-forms/uploads/php/files/d78e6d99369f4c6d015bd944c480b018/65062124326.pdfIn PDF document text
    • https://mkart.it/uploads/file/jesugisovuxigif.pdfIn PDF document text
    • https://icicle-mountaineering.ltd.uk/ckfinder/userfiles/files/dezoxujesenivewudozizitu.pdfIn PDF document text
    • https://agrocare.ro/ckfinder/userfiles/files/konilalefime.pdfIn PDF document text
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b17b9348d5---88617992845.pdfIn PDF document text
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614ad471b613a---63998099864.pdfIn PDF document text
    • http://konstruktor33.ru/app/webroot/files/files/muvewedurepepusogesej.pdfIn PDF document text
    • http://historico.uts.edu.co/portal/app/ckfinder/userfiles/files/59167642524.pdfIn PDF document text
    • http://gerocuki.hu/user/file/timofijiwajep.pdfIn PDF document text
    • https://tavio.ru/files/file/dopojaxuwel.pdfIn PDF document text
    • http://skene.es/userfiles/file/32768598067.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/849dab9d3841e9e9cb8faafb863f742a/32493625698.pdfIn PDF document text
    • https://ww150007.linebot.net/upfile/files/20210903113737.pdfIn PDF document text
    • http://jun-travel.com/userfiles/file/wojoxujovomugegika.pdfIn PDF document text
    • https://goez3.com/10005001208290177/ckfinder/userfiles/files/25335478780.pdfIn PDF document text
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613a4afe6f8d7---ganufivijajiso.pdfIn PDF document text
    • http://gearonlaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/porikexuw.pdfIn PDF document text
    • https://alves.bg/ckfinder/userfiles/files/rewalenofibubaso.pdfIn PDF document text
    • https://tybistanbul.org/resimler/files/wifuboga.pdfIn PDF document text
    • https://menokatea.com/ckfinder/userfiles/files/57449447503.pdfIn PDF document text
    • https://mgs-on-track.com/uploads/misc/files/noboweko.pdfIn PDF document text
    • http://nkmate.com/FileData/ckfinder/files/20210901_97C264244E4FFBFE.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_off0000b62d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB62D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ce3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE3F 18688 bytes
SHA-256: f1f89bdeae2d94df292639beef0394e569fa0bb3e4092fb792bb9b10653ac9d2
font_02_sfnt_off0000fdb5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDB5 10772 bytes
SHA-256: 48fae48f63e328e2f5b0e07fe15700c6d745d71797f61a7cee96bb7df33ae3ff