Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d0cf4881802979…

MALICIOUS

PDF

69.2 KB Created: 2021-04-15 18:06:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 64deb801bd52e7fc1bfc9dbb8768418b SHA-1: 6f9d55a27e344bcdb822cec669666d1ea84c70e7 SHA-256: 81d0cf488180297943ba701270526c883883ddbb2160c898859279c53d305125
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution T1059.007 JavaScript

The sample was detected as a malicious PDF by ML classifiers and ClamAV, indicating it's likely a phishing or malware distribution lure. The PDF contains numerous embedded URLs pointing to domains that appear to be part of a link farm, suggesting a tactic to obscure the final malicious destination. While no scripts were explicitly extracted, the PDF structure and embedded URLs are strong indicators of malicious intent, likely involving the exploitation of PDF vulnerabilities or social engineering to redirect the user.

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://europa-ts.ru/sites/default/files/webform/6529842099.pdf In PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/27017481005.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/nufideleze.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/noranixuguwetepefosobad.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/tekuxegejarikuferibo.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/41850888982.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/80982398497.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/61975266633.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/wefegazeketalewawer.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/bofuwidesuxugebogaxa.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/togivem.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/powevalixerofewum.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/85278691340.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/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=lost+and+found+bluford+series+summaryPDF link annotation
    • 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_off0000d269.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD269 5236 bytes
SHA-256: 697847ca798724e65cd2e76cdf88e4aba9ddfa210757d7d98e754233e4461eb4
font_01_sfnt_off0000e42d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE42D 10552 bytes
SHA-256: 5f4cc97eabd1fadc7321bf62aa7a5def27371fff7ef461a30ee704d96e44b4e4

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