Malicious PDF — malware analysis report

Static analysis result for SHA-256 99845d40e896b071…

MALICIOUS

PDF

79.9 KB Created: 2021-09-18 06:50:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: acdcd36c479d141c8158d5cc55edf44c SHA-1: 9ba2802185f26b584a6b4032c6234af680c9a2e0 SHA-256: 99845d40e896b0718a46f68d45ed36fa7536a45c6d55ae072cda42b540a4dc44
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. The document contains a link farm that points to numerous external URLs, many hosted on compromised WordPress sites or disposable domains, suggesting an attempt to redirect users to malicious content. Embedded JavaScript was also detected, likely used to facilitate the redirection or exploit.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://serramentisiciliano.it/userfiles/files/71559339095.pdf In PDF document text
    • http://gasthaus-steinkirchen.de/img/editor/file/71498174360.pdfIn PDF document text
    • https://rubyyadav.com/nbloom/fckuploads/file/woliwojeragaz.pdfIn PDF document text
    • https://szabobuszberles.hu/files/files/zasiz.pdfIn PDF document text
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/16143cb970d954---zunemo.pdfIn PDF document text
    • https://thegioibaobicarton.com/Images_upload/files/xuxonasaz.pdfIn PDF document text
    • http://projecthouse.bg/uploads/CKfinder/files/duvifisu.pdfIn PDF document text
    • http://vuatoyen.com/uploads/userfiles/file/jatile.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16134f5162f33d---jafuviwuwebazesomo.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/f80ea0a8896341e288510d92b2b8a29f/zowakopemakuzizanarex.pdfIn PDF document text
    • http://beming.com/ressource/site-image/files/purobabesevowixonitowe.pdfIn PDF document text
    • http://888spirits.com/userfiles/file/23227899361.pdfIn PDF document text
    • http://marketypik.pl/zdjecia/fck/file/46577757798.pdfIn PDF document text
    • https://jsptti.com/ckeditor/ckfinder/userfiles/files/74915818429.pdfIn PDF document text
    • http://fueandhair.com/userfiles/files/gopefosenexisak.pdfIn PDF document text
    • http://santiagoporter.com/js/ckfinder/core/connector/php/files/5407095348.pdfIn PDF document text
    • http://in-dapt.com/wp-content/plugins/formcraft/file-upload/server/content/files/161348e9a838bc---bezexefijigiferoxivoj.pdfIn PDF document text
    • http://ambvetsanprospero.eu/userfiles/files/85993630248.pdfIn PDF document text
    • http://www.horakgolf.cz/ckfinder/userfiles/files/47972986722.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=errol+street+medicalPDF link annotation
    • https://www.assessment.unibe.ch/app/webroot/js/ckfinder/userfiles/files/26329121344.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_off0000d342.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD342 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000eb54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB54 18188 bytes
SHA-256: c40668e45c0df1f1a2c9ae43173a54e09f16c3ceadc91cf1d7548a297790bb86
font_02_sfnt_off00011a95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A95 10412 bytes
SHA-256: 56cd62308108d89313917fb498493defd42b58ca80a803161f8d26216dd6e515