Malicious PDF — malware analysis report

Static analysis result for SHA-256 feb9b0d1c2a53288…

MALICIOUS

PDF

77.1 KB Created: 2021-06-24 21:58:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 5d7496e18a8fbb375bd8e5debfba4976 SHA-1: e9c7797c1267b8ab53edc1e083a395f3425f3ac5 SHA-256: feb9b0d1c2a53288e9d84593b3062b7a957f47fdca8f74f4ee3d1a83b7d46f62
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it's a link farm pointing to compromised WordPress sites. The document body, though heavily obfuscated, contains text related to 'pronunciation rubric esl' and 'wkhtmltopdf', suggesting a lure. The embedded URLs are likely used to redirect users to malicious content or download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://birons.net/wp-content/plugins/super-forms/uploads/php/files/9ee36b8ffe78e352cca029cdbd56fb59/fawemejug.pdf In PDF document text
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081045f44ce4---kukumoketotawokoxenose.pdfIn PDF document text
    • http://kingspec.su/wp-content/plugins/super-forms/uploads/php/files/vk6uqkcsp39o2htpuh4q5ugv8v/zovoxipiretamu.pdfIn PDF document text
    • http://co-mit.com/uploads/files/xixofel.pdfIn PDF document text
    • http://cetinelektrik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1607ab06b22cfd---82302939242.pdfIn PDF document text
    • http://bergfin.se/wp-content/plugins/formcraft/file-upload/server/content/files/16085e946aad54---jaxexewovenixomumiso.pdfIn PDF document text
    • https://muzeumkonstancina.pl/attachments/file/nexazesi.pdfIn PDF document text
    • https://halobysciton.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e059b2425a---wadesexitaposoz.pdfIn PDF document text
    • https://www.mixedclass.com.au/wp-content/plugins/super-forms/uploads/php/files/5n6ah4pk7pp0nudddrgbjoouuv/vabuk.pdfIn PDF document text
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/cvc892sgcq4iheraue3bdsdmd2/73629575603.pdfIn PDF document text
    • http://vilaportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ca21ce5ca5---jedazitonemukewesugiv.pdfIn PDF document text
    • http://batiment-tunisie.com/userfiles/file/vebikazakitalas.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/4186f7af33d250bd453550be1a49ac9d/gedewunezadusinosogadogi.pdfIn PDF document text
    • https://www.frankcapassoandsons.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a3c45d61f66---37063726255.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1609efe556e2f7---jefimisalikisojogitimi.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=pronunciation+rubric+eslPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f20d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF20D 4936 bytes
SHA-256: 34c60db38f4dd6ae78617a3a736d649b375381e552800532cbf3a05ba5e62577
font_01_sfnt_off000102dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102DC 10872 bytes
SHA-256: 57d7c612dcf62d979d0969262e379a11d8220ddf6a484a6fe7c4d941e2bf22a9