Malicious PDF — malware analysis report

Static analysis result for SHA-256 31afe1ae35e94eb1…

MALICIOUS

PDF

75.4 KB Created: 2021-09-08 00:20:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: d2e5ed9009aaf0bcc290f818dc9936e7 SHA-1: 669a06c8221551fd8cde5fc0bd89ffb3f14bc7d6 SHA-256: 31afe1ae35e94eb1a84c75eb2a1b78f6121ba6f62bbd7eb7d81d8b2d7f36cd6b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable domains, suggesting a phishing or malware distribution attempt. The presence of embedded URLs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicate an effort to create a link farm, likely to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://laborke.ru/uplcv?utm_term=respiratory+system+practice+test+pdf PDF link annotation
    • https://nbretail.com.vn/ckfinder/userfiles/files/pajetofufuw.pdfIn PDF document text
    • http://businessvaluationapp.com//fck_files/file/27104028169.pdfIn PDF document text
    • https://www.cr-sdc.org/wp-content/plugins/super-forms/uploads/php/files/004405e8e2f4ab32ad52176d51d39a84/58117689596.pdfIn PDF document text
    • http://mazurubezpieczenia.pl/zdjecia/fck/file/zofudogiwirixojalowotos.pdfIn PDF document text
    • https://burstallconrad.com/editor_files/file/71057992139.pdfIn PDF document text
    • http://ngocvietbungalow.com/upload/files/6838911522.pdfIn PDF document text
    • http://sonnenheizung.ch/fckeditor/editor/images/file/pinenip.pdfIn PDF document text
    • http://monkeytailranchdonation.org/clients/e/e8/e82116dd0b5861b0917add2a69208af2/File/gaxaruxewuxapusakakusidi.pdfIn PDF document text
    • http://laihoawedding.com/app/webroot/upload/files/92876434043.pdfIn PDF document text
    • http://lamorenj.com/userfiles/files/kavemozigalixelifenexise.pdfIn PDF document text
    • https://bucatariizidite.ro/printuri-fi/files/34317101702.pdfIn PDF document text
    • https://mithermomix.com.mx/wp-content/plugins/super-forms/uploads/php/files/a9209698908674ea81be3ed2cab30a4c/63911526782.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/bd3babb6dc7ab97dfbddbbe403d9e72f/70014015176.pdfIn PDF document text
    • http://matrixuniverzum.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16075a9be7dd84---62980873009.pdfIn PDF document text
    • http://mariautonoleggiomarsala.it/userfiles/files/40018285872.pdfIn PDF document text
    • https://senarathgroup.lk/assets/media/file/waziwijinalowevoro.pdfIn PDF document text
    • https://www.igescanada.com/ckfinder/userfiles/files/58406667925.pdfIn PDF document text
    • https://autoandtruckrepair.net/nbloom/fckuploads/file/80293923852.pdfIn PDF document text
    • http://montex.pro/uploads/userfiles/file/33598204450.pdfIn PDF document text
    • http://dabbleanddesign.com/clients/c/c6/c60e280709801842a26e47e23f21f170/File/78173288579.pdfIn PDF document text
    • http://anonelectronics.com/admin/fckeditor/editor/filemanager/connectors/php/upload_jpg/file/202104291132444718.pdfIn PDF document text
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070dc72bb1c4---67355458994.pdfIn PDF document text
    • https://psiakocky-potisk.cz/webpagebuilder/ckfinder/userfiles/files/zutibuseli.pdfIn PDF document text
    • https://golf-tout-terrain.com/publish/page/file/nuluge.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_off0000c2a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC2A6 10792 bytes
SHA-256: ced07475e93e26321e7cf6689b4c3342e05a138874f7503778bdb7d2a9156b03
font_01_sfnt_off0000db99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB99 17092 bytes
SHA-256: 5b5361aebbb2aa61f29fc689c2c2de2bff60886349809064da7f452ead07d436
font_02_sfnt_off000107b8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107B8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1