Malicious PDF — malware analysis report

Static analysis result for SHA-256 9f3f923119247f5f…

MALICIOUS

PDF

74.9 KB Created: 2021-06-15 10:04:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 86f3a3ca1bf21cf7e984fd94e41f891c SHA-1: 7a564d5a1ef57524f433af81d60db386a39f574c SHA-256: 9f3f923119247f5f57b545f7164035d7cded5551f49292fe3af5f43013613d10
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous links to external websites, many hosted on compromised WordPress installations, suggesting a link farm or phishing lure. The document body, though heavily obfuscated, contains references to 'reading materials for grade 5 english pdf' and 'wkhtmltopdf', indicating a potential attempt to disguise malicious links as educational content. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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=reading+materials+for+grade+5+english+pdf PDF link annotation
    • https://www.businesswatchguardingservices.co.uk/wp-content/plugins/super-forms/uploads/php/files/i93qtrsvfm1va83183c1b7lvig/31976967643.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a8cf7cb0d49---88830976886.pdfIn PDF document text
    • https://legacyltg.com/wp-content/plugins/super-forms/uploads/php/files/29480a9bfbd56a2926051afc0de3245d/11728382535.pdfIn PDF document text
    • https://otelnamore.com/wp-content/plugins/super-forms/uploads/php/files/30c8b24dc3f4e97501ff1217d0d345b0/87292821153.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/jijaw.pdfIn PDF document text
    • https://aspaeng.com/files/image/files/jimuzixasofup.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c31681884e2---65733516289.pdfIn PDF document text
    • https://www.northwoodmedical.ca/wp-content/plugins/super-forms/uploads/php/files/g52osiua1v62c6i0u588flstak/43701494109.pdfIn PDF document text
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607361157defe---mivagivedajubuxevajapiri.pdfIn PDF document text
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/160aa6e5683e07---risodolexizipidepofinizi.pdfIn PDF document text
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/d1461a24682409b35faecca6f8a0f941/95103221421.pdfIn PDF document text
    • https://alutat.com/data/file/nujapa.pdfIn PDF document text
    • https://teenvolunteerdallas.org/wp-content/plugins/super-forms/uploads/php/files/5494790403658eea1cb1dc1e87f8f208/57815101733.pdfIn PDF document text
    • http://psychologkmalinowska.pl/ckfinder/userfiles/files/natakiparufegivutisod.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_off0000e768.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE768 5584 bytes
SHA-256: e1954189171758c50a076408c20acdab53a90d63c2ebc08619b30460fb9b09f4
font_01_sfnt_off0000fa48.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA48 10640 bytes
SHA-256: 9aa68d01eed91d12f09db231ab523c013dbe2426a333d8ff99bc57f74a443646