Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b31147689097fc…

MALICIOUS

PDF

73.2 KB Created: 2021-04-23 17:49:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: a7c512d81a3da046283154206b91bb9f SHA-1: 7f864a1a8e5da438b6aa84db4ef0a74fcb9beb6a SHA-256: 81b31147689097fc5f13f05681a221bf0b1dfd188c6d6f7c5e7d4d2cc33c0d35
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, with one heuristic specifically identifying it as a link farm on disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. Although no scripts were explicitly extracted, the PDF structure and embedded links suggest 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 https://www.natsihwa.org.au/sites/default/files/webform/doxuwekuwazomiloxeri.pdf In PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/49428740932.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/kivalin.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/69174909787.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/balulata.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/durigoxilakomisi.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/2944445507.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/58994315224.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/24974410021.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/4264017636.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/22206840813.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=how+to+play+m+audio+keystation+49ePDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/21338807989.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/78922999772.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/vifixofixif.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d4cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4CB 5356 bytes
SHA-256: d0f9af548a768e44f5a7094a079e64345660b350a1be2d420a7cedfb83533d45
font_01_sfnt_off0000e701.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE701 10176 bytes
SHA-256: 6b068aebf078e06294af7d4943aeb119ae041b8847b12d46cb69b85d647dc33d
font_02_sfnt_off000109d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109D4 4324 bytes
SHA-256: 7f6049e5011acf0e8581793f2bc2bb947aac2929fdb77abc318b2a6155c1ef71

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