Malicious PDF — malware analysis report

Static analysis result for SHA-256 91da7486287dfecf…

MALICIOUS

PDF

83.4 KB Created: 2021-06-13 14:31:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: 0558dd515a337621b3bb00f801497d16 SHA-1: 03c961e5a6befd8cdff6163a09416a932c99e3ae SHA-256: 91da7486287dfecfdc7c2f93ca150a10b2dec9733072e5513bf8791bbe90b660
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous embedded URLs, many pointing to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, contains metadata related to 'wkhtmltopdf' and a date, but no clear user-facing text. The primary attack pattern involves leveraging these links for phishing or malware distribution.

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://irlanc.ru/uplcv?utm_term=arms+warrior+pvp+enchants PDF link annotation
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1606cac770ebb7---nuvaxusupedivuviluzopu.pdfIn PDF document text
    • http://bfr-bialapodlaska.pl/userfiles/file/27219572041.pdfIn PDF document text
    • http://recrute.fr/files/files/23372798478.pdfIn PDF document text
    • https://divorcioconsensual.com.br/wp-content/plugins/super-forms/uploads/php/files/b5147f8e378ded7905ee35471e5d5283/morekigi.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa8170255a1---89475883939.pdfIn PDF document text
    • https://motionslam.com/wp-content/plugins/super-forms/uploads/php/files/9187d7e2ab6c6537ba0d9052c21a487e/58786114820.pdfIn PDF document text
    • https://www.medicalart.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16099d055e0ff0---53066354974.pdfIn PDF document text
    • http://sevimticaret.net/userfiles/file/nikazaned.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/1607f9629cb54d---88274579213.pdfIn PDF document text
    • https://elitteaccesorios.com/wp-content/plugins/super-forms/uploads/php/files/u5kt162lp5kfdajv8r0qnt7k3m/dodogosomalufagejanopudax.pdfIn PDF document text
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/eee89d20fcd80aa80e2f1fff913a1ecb/jebonotuv.pdfIn PDF document text
    • https://www.advids.co/wp-content/plugins/formcraft/file-upload/server/content/files/1609a74d4b0d5f---kegelowelavemofedozed.pdfIn PDF document text
    • https://bd-sokolovska.eu/userfiles/file/fisovimovuxufabini.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb6394258e---mupujok.pdfIn PDF document text
    • https://xn----7sbabak5acz7byau.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/aa2125f72818d896014cd4d25083fd96/pumesavepoduni.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_off0001079f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1079F 5280 bytes
SHA-256: 996c8c20c730550d95a43ed968f0d93ca4d784ebd2251427a936b284722435e1
font_01_sfnt_off0001197c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1197C 11020 bytes
SHA-256: 30729541cce8d6b7b17bd432c438fc8936aaf5a0eb818fb5ca337f757d7f6034