Malicious PDF — malware analysis report

Static analysis result for SHA-256 ca23a31a90d90930…

MALICIOUS

PDF

83.1 KB Created: 2021-09-18 16:57:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 32113060d40a7cae7b86f9dd5fba4df8 SHA-1: ebf83d1d65340d284d9e8b11c6c617a4ad4861a2 SHA-256: ca23a31a90d90930bb7421a192123939d18a5d47d3d7ae6fd85233a4c1f8873f
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to disposable domains, indicating a link farm or phishing attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports the conclusion that this PDF is part of a scheme to distribute malicious content or phish users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

Heuristics 5

  • 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 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 http://cafehinglung.com/uploads/files/xogemesex.pdf In PDF document text
    • https://istanbularicilikfestivali.com/upload/ckfinder/files/givigeb.pdfIn PDF document text
    • https://eletmodguru.hu/files/files/94008140490.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-9-4/20210904205951602342.pdfIn PDF document text
    • http://metallpress.ru/files/48100054196.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/161374df73f3d8---28421096320.pdfIn PDF document text
    • https://www.corpeverest.com/ckfinder/userfiles/files/7541366369.pdfIn PDF document text
    • https://imotrading.com/images/userfiles/guluzowo.pdfIn PDF document text
    • https://malmospelmanslag.se/userfiles/file/tekezudefasi.pdfIn PDF document text
    • https://dadesigning.com/daduserfiles/files/nesunulafefewut.pdfIn PDF document text
    • http://www.bufolari.com/public/immagini/file/boxazabenomur.pdfIn PDF document text
    • http://sportsgarten.com/editorData/file/masokefujotaxigugat.pdfIn PDF document text
    • https://zlato-invest.cz/upload/files/pitupuvimunokazina.pdfIn PDF document text
    • http://nhungbaithuocnam.com/img-tvdl/files/13544873194.pdfIn PDF document text
    • http://app0.linkeo.it/ckfinder/userfiles/files/51691858086.pdfIn PDF document text
    • https://haps.company/wp-content/plugins/super-forms/uploads/php/files/6ed6603dcefbb9dccdbc0ec976298114/fajisidomilokaniga.pdfIn PDF document text
    • https://hygradeinsulators.com/images/uploads/file/ragezibazenubuzi.pdfIn PDF document text
    • https://www.potravinyav21.cz/ckfinder/userfiles/files/dugutakapus.pdfIn PDF document text
    • https://perfecthospitals.com/FCKeditor/file/80353721769.pdfIn PDF document text
    • http://whuntex.info/userfiles/file/45875215811.pdfIn PDF document text
    • http://www.c-l-r-p.com/admin/ckfinder/userfiles/files/14749323129.pdfIn PDF document text
    • http://hai-bi.com/uploads/files/202109172023231999.pdfIn PDF document text
    • http://dailythang.com/userfiles/files/jipakemumuxajoxejelasome.pdfIn PDF document text
    • http://ck-tct.ru/userfiles/file/jifukexaberavivu.pdfIn PDF document text
    • https://pointvirgule.ca/upload/editor/file/kufemag.pdfIn PDF document text
    • http://eau-msu.ru/ckfinder/userfiles/files/vubumunafitigosorukokosal.pdfIn PDF document text
    • https://dveropolis.ru/upload_picture/35596932231.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=convert+mp3+to+android+ringtonePDF 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_off0000e192.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE192 10792 bytes
SHA-256: 081ae21b6324f7c9681e2e87ac64a627610f28df197fb69a68e09847c2ea4b54
font_01_sfnt_off0000fa3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA3B 17000 bytes
SHA-256: e44ea5cd1cbd3468b978883355ca60cceb3b0d5d1709ace79d909164aee20775
font_02_sfnt_off00012650.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12650 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1