Malicious PDF — malware analysis report

Static analysis result for SHA-256 a851b6b56b23b859…

MALICIOUS

PDF

74.0 KB Created: 2021-04-25 07:45:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 1ee2ccd217b798045d82b291806b93ce SHA-1: 28cc00d6f8de4f9603c13af51e43d3997f1e3be5 SHA-256: a851b6b56b23b859cd0586f8e8a14bd997c40fe8100843147d1fd20d45170193
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 trojan. It contains numerous external links, many pointing to disposable domains, suggesting a link farm or redirection mechanism. While no scripts were explicitly extracted, the PDF structure and heuristic firings indicate it's designed to lead users to potentially harmful external content.

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.a1touchsolution.nl/sites/default/files/56489371510.pdf In PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/80411930416.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/fulakosilukubusovugatupus.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/sowasipaxezok.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/5308316073.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/julojulixizegusu.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/95866450710.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/3097059720.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/21555212736.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/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=how+to+transfer+photos+from+samsung+s5+to+micro+sd+cardPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/50156150340.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/18848190838.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/fasulegok.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_off0000e0a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0A0 5716 bytes
SHA-256: 796854e6bc3d1cd5a5e33f917f9fa864eea4e8b03553a4fb9f71edad56422d01
font_01_sfnt_off0000f406.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF406 11828 bytes
SHA-256: d8886a3361afbbc84a5ec32ff829a65a84ef3d5f4f3a475733921540331dc2b6