Malicious PDF — malware analysis report

Static analysis result for SHA-256 af8f9d5088cbee29…

MALICIOUS

PDF

78.8 KB Created: 2021-04-07 06:44:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 92869abbf0e7e3913bb276c598614932 SHA-1: 756f6d7ddf6e1d35773a3cc978cdfce565930a3a SHA-256: af8f9d5088cbee297b13531c94bde6bb652de7825dd3255e54719d88a71925a9
126 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to disposable domains, suggesting it functions as a link farm. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a non-clustered link farm on disposable hosting, and the presence of 'utm_term_redirector=True' suggests tracking or obfuscation. While no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a phishing or malware distribution attempt, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://www.sumnercountyhospital.org/sites/default/files/webform/sinuwoxifazuroli.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/9979090083.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/6948618973.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/zarogoluvesiriwameb.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/lomaxitafuvutatu.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/95147346690.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/wajuso.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/80982398497.pdfIn PDF document text
    • http://russian-ice-spb.ru/sites/default/files/webform/files/69309865186.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/71027525942.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/kokibilelage.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/dadesiludidogujuta.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/doxuwekuwazomiloxeri.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/35039450578.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=aldrich+catalog+handbook+of+fine+chemicals+pdfPDF link annotation
    • https://lib.asu.edu/system/files/webform/90369837207.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/midari.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/48950823745.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/janewif.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/46273532178.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_off0000f357.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF357 5760 bytes
SHA-256: 0c42b469aa4185da3edc31bad30aabfcb2fa67c883084e82e3862d66e47378d9
font_01_sfnt_off000106c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106C4 11512 bytes
SHA-256: 78c047e04f24ab14d8861ed38fd01aa917cee09d63cc07c0e8f715eb9a52e567

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