Malicious PDF — malware analysis report

Static analysis result for SHA-256 df1aa31a477cb167…

MALICIOUS

PDF

76.4 KB Created: 2021-06-13 04:46:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 1e809760a8f4e9f7a1514e14724013ce SHA-1: 5b6240991f99189085176659c6fd25b6c1195ee5 SHA-256: df1aa31a477cb16775d478b17e5feba1d9419e6ada06dc62ae7b4d270cdfaf23
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains a link farm pointing to multiple compromised WordPress sites, designed to trick users into downloading malicious files disguised as a PDF reader. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the presence of numerous external links suggests a downloader or phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

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://krisoc.ru/uplcv?utm_term=pdf+reader+apk+small+size PDF link annotation
    • https://suemsas.com/wp-content/plugins/super-forms/uploads/php/files/ifjk637lbvemtkb007qufr2fm2/bavofekenuvulikofirikul.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d92660635c---63530641666.pdfIn PDF document text
    • https://www.eziblank.com/wp-content/plugins/super-forms/uploads/php/files/md4ivtd87snf6m40r5siahfo33/68161018790.pdfIn PDF document text
    • http://festivaldeliteraturadepereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/16089a75818f9d---pixawurasenalatipuzupel.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/127bd29e19713de19d4249e03c207cc1/86493496057.pdfIn PDF document text
    • https://bojovicsirogojno.com//files/nawurusawepuwipuvedi.pdfIn PDF document text
    • http://personnelstrategies.net/userfiles/file/wajesefinuvuvuxesa.pdfIn PDF document text
    • http://www.anieliasfx.com/uploads/textareas/file/66507212878.pdfIn PDF document text
    • http://wypelnienia.kratex.pl/wp-content/plugins/super-forms/uploads/php/files/8ea227e4735b389f8eb03f507c354165/bifuruzutesigasazawamuki.pdfIn PDF document text
    • http://rund.cz/UserFiles/File/76184305289.pdfIn PDF document text
    • https://laxmigrouppune.com/wp-content/plugins/super-forms/uploads/php/files/ccbb02ee73a14307476aa66795571fab/vesifekudumibefofamalit.pdfIn PDF document text
    • http://sts-logistika.ru/wp-content/plugins/super-forms/uploads/php/files/b8edf59fe0808e979889483e0a54dd63/56520186651.pdfIn PDF document text
    • http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160ba8883da329---91591493241.pdfIn PDF document text
    • https://www.apartamentselsllacs.com/wp-content/plugins/super-forms/uploads/php/files/g1br31p4pseetbe7umsop40j5b/fowekutilofaweselefa.pdfIn PDF document text
    • http://phillipwhiting.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608221f11b887---53615794425.pdfIn PDF document text
    • http://bhs-class1957.com/clients/35434/File/wototugoloveweviwovev.pdfIn PDF document text
    • https://regeneracion-capilar.com/wp-content/plugins/super-forms/uploads/php/files/666e0a0f049d6bfdfe8e59859d327308/wuderubemikati.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ee0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE0D 5304 bytes
SHA-256: d0ab0e0766af96c31012bd6fd8e5bee2f79a647f0565b23ff12dc48a685300fe
font_01_sfnt_off00010011.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10011 10356 bytes
SHA-256: 19fa1fd984d3ebfd69c8e9788fc340289c9b079be9c596747398a2a25d41e483