Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d9f7480d0a44f47…

MALICIOUS

PDF

67.4 KB Created: 2021-04-21 17:38:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: d54366a0a4cc407d9c84c849b3a73a24 SHA-1: d4fca3908187e349efdec7547d6abfbc119673aa SHA-256: 4d9f7480d0a44f47fe268b23222b69ba5eb3a27a4b2f4202b0e4fb3e22157b7d
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. The document body, though heavily obfuscated, contains text related to calibrating a thermometer, which serves as a lure. The presence of numerous external URIs, many pointing to potentially compromised legitimate sites, suggests a link farm or redirection mechanism designed to lead users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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://www.natsihwa.org.au/sites/default/files/webform/zolevijovexoneda.pdf In PDF document text
    • https://www.jwico.com/sites/default/files/webform/23528315583.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/goxara.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/kuvusuwube.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/nuwirofu.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/bekam.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/wozat.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/YTWXjIUwRh0/uplcv?utm_term=how+to+calibrate+braun+thermoscan+ear+thermometerPDF link annotation
    • https://www.vub.be/sites/vub/files/webform/16824703900.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/wawojamifot.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/53082175038.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_off0000c94a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC94A 5232 bytes
SHA-256: 480daf80b8bf02bb6a1a79544fb3f1f1e0ed62ed865f0ec01b7fe31bcaeff4ed
font_01_sfnt_off0000daf6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAF6 11160 bytes
SHA-256: 75292c473170bd73a657a2b93c7cfd4267a75b13a9418a3465586396951f4c32

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