Malicious PDF — malware analysis report

Static analysis result for SHA-256 b3c4d19316b4febe…

MALICIOUS

PDF

67.6 KB Created: 2021-04-19 00:31:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: a0a4e59e271edeec10150f51381aa684 SHA-1: 28aaa277ce1dfc5269771bdbbde73ec81330c693 SHA-256: b3c4d19316b4febe4f0b329ff44e7c8617d7131fea12ba414578969e19be3dba
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to disposable domains or link farms, suggesting an attempt to redirect users to malicious content. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a strategy to obscure the true destination of the links.

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 http://cicatsalud.com/html/sites/default/files/webform/28693943460.pdf In PDF document text
    • https://aboss.by/sites/default/files/webform/12404161593.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/sidetarebuw.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/15691680518.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/nojezajewi.pdfIn PDF document text
    • https://architecturaldesigninc.com/sites/default/files/vudezuluxi.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/dagen.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/44437875789.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/taxebuvokorutupimapo.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/Om9ozkHLxGw/uplcv?utm_term=what+should+my+air+fuel+ratio+be+at+idlePDF link annotation
    • https://community.princeton.edu/system/files/webform/42655509772.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/47045932069.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_off0000cba5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBA5 5404 bytes
SHA-256: 99231cf4454df3f8b64035ff6bd8c67b8e753cad4a473b3091cb4c1126ccde6d
font_01_sfnt_off0000dde7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDE7 10528 bytes
SHA-256: 534a0846544751b09a15273c86ce50af820306793264651116a655d39b787fb1

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