Malicious PDF — malware analysis report

Static analysis result for SHA-256 c303bff605605009…

MALICIOUS

PDF

68.7 KB Created: 2021-04-19 04:20:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: a12a373c05c4128dfbf3138193a688da SHA-1: 7b566385d47aaac65136770e5a0ad6c3d9c22280 SHA-256: c303bff6056050093a9edc42bdd3808083d16f32ef61af7b90ff198d35d87287
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing or trojan. Heuristic analysis identified it as a link farm with numerous external URIs, many pointing to disposable domains. The document body, though heavily obfuscated, contains references to wkhtmltopdf and a date, suggesting it was generated programmatically. The presence of embedded URLs and the link farm nature strongly indicate an attempt to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://www.grotekeukens.be/sites/default/files/webform/gmawards2018/30150103061.pdf In PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/37570077738.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/28961662769.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/12132802610.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/zarogoluvesiriwameb.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/10891008032.pdfIn PDF document text
    • https://www.afscme65.org/system/files/webform/96479551545.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/47965191786.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/7486912807.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/jokefogebefuzifuzew.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/vewamilobofesiwukor.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/tirudekamevajoluzagobumi.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/meratasadif.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/21691652676.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/pexutagizoniged.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=is+it+worth+saving+your+virginity+for+marriagePDF link annotation
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/37488496184.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d18b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD18B 5340 bytes
SHA-256: 6022a38d9f845fd7c8e40c3ea047add504996121385f633509048797dc870ed9
font_01_sfnt_off0000e3ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3AB 9956 bytes
SHA-256: 1feaec4a4753964295498ce428552199df1fb5033d9a7a646d10489841193b47

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