Malicious PDF — malware analysis report

Static analysis result for SHA-256 191d8b787149c429…

MALICIOUS

PDF

70.4 KB Created: 2021-04-11 03:00:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 8838c4bd943843b61b40e5337f2af737 SHA-1: 1b66bcb551fdf2debbc0ad71b851a9cf58aaef8f SHA-256: 191d8b787149c429e0f27cce9f2b2e4f70ee046c29f07f5dcd7c06258238eeb1
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. Heuristics indicate it functions as a link farm, directing users to multiple distinct hosts, with a high likelihood of leading to malicious content or further exploitation. Although no scripts were explicitly extracted, the PDF structure and the nature of the heuristics suggest an attempt to redirect users to potentially harmful external resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/tojawi.pdf In PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/84972388600.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/gewematumupam.pdfIn PDF document text
    • http://www.pacificsportfraservalley.com/sites/default/files/webform/newusagolepilukakatukus.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/vonasajevevedatenalezeb.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/danodajanenalidadalibebav.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/sidetarebuw.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/kuvusuwube.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/27804174203.pdfIn PDF document text
    • https://www.afscme65.org/system/files/webform/tikat.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/27880179426.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/YTWXjIUwRh0/uplcv?utm_term=steven+jesse+bernsteinPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/83605599331.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/wetesagepe.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/87767597376.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/7842358922.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_off0000dac3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAC3 4816 bytes
SHA-256: b6b093ec675a4eb845129d9c345011cf2dba17da7ff8b737857f9037339e9f77
font_01_sfnt_off0000eb3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB3A 10236 bytes
SHA-256: e73ae32f742890879e23b83fde7674345027e1050b74084fe49df4729fe56586

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