Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a6d73bafff14453…

MALICIOUS

PDF

73.6 KB Created: 2021-09-19 02:59:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: d05f6499a47d9efcf4794f4ff251dcd9 SHA-1: 65b4d3f1f4e84cea386661849f7194ad53f58eda SHA-256: 4a6d73bafff14453071f877780311b6e021bf9aa71473746af616d373bd12a60
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with multiple heuristics indicating it functions as a link farm. The PDF contains numerous external URIs pointing to various domains, many of which are likely disposable, suggesting an attempt to distribute malicious content or conduct phishing. No scripts were extracted, but the overall structure and heuristic firings strongly suggest a malicious intent to redirect users to harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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 https://krisoc.ru/uplcv?utm_term=my+android+box+keeps+buffering PDF link annotation
    • https://atasuorganiktarim.com/upload/ckfinder/files/bimalejelewufunep.pdfIn PDF document text
    • http://yasaitogo.com/uploads/files/gudotatugasikofarawaj.pdfIn PDF document text
    • http://peterpan1996.it/userfiles/files/naroromeseguxajuxopejan.pdfIn PDF document text
    • http://ubytovani-budejovice.cz/picture/vtextu/file/fesogujodipaxuxafi.pdfIn PDF document text
    • http://abwvictory.com/uploads/files/26257753833.pdfIn PDF document text
    • https://5uempat.com/contents/files/vekumutevobajojuvorigis.pdfIn PDF document text
    • https://ketex.com/trcgp/ckfinder/userfiles/files/bopaperejadeza.pdfIn PDF document text
    • http://euroambulans.pl/userfiles/file/91932833190.pdfIn PDF document text
    • http://santabruna.cl/upload/file/sasubolebulisudususit.pdfIn PDF document text
    • http://www.omt.ntou.edu.tw/ckfinder/userfiles/files/vuxakixalizemepemonan.pdfIn PDF document text
    • http://funkyspa.net/ckfinder/userfiles/files/mujomaluvojiwon.pdfIn PDF document text
    • https://novinfasteners.com/userfiles/file/7735412245.pdfIn PDF document text
    • http://abwcoliseum.com/uploads/files/81615846541.pdfIn PDF document text
    • http://energosol.pl/images_cms/file/43896409492.pdfIn PDF document text
    • http://karinameal.ru/imgdish/files/pozegarovaxolifisepufot.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/5b10b320eb7d1c21d5b335c41dc69671/rutotugekowijagolozovo.pdfIn PDF document text
    • https://www.nickelmarket.co.za/includes/ckfinder/userfiles/files/xesefizarogajakelinez.pdfIn PDF document text
    • http://mnogonomerov.ru/uploads/file/4887040582.pdfIn PDF document text
    • http://idevicesplus.nl/app/webroot/files/userfiles/files/pujuraf.pdfIn PDF document text
    • https://angkoronetour.com/userfiles/file/pasinunevijajagosixirov.pdfIn PDF document text
    • http://bukhatirhomes.com/userfiles/file/buxutezinokuronomuli.pdfIn PDF document text
    • http://suliaok.com/v15/Upload/file/20219131924199472.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e3ed77f5a5---negilob.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_off0000bb68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB68 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d37f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD37F 11068 bytes
SHA-256: d036ab7a966a64f08066a1e922161dae6f8e2a3d881723c44487eb0b68aeb22c
font_02_sfnt_off0000ecf8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECF8 17172 bytes
SHA-256: 8a4dd0d0da4024bf9efe567b0ec65bda1ac41a0bf7fdae19672e3c99a0e4ef0b