Malicious PDF — malware analysis report

Static analysis result for SHA-256 19d75aefcc6bc541…

MALICIOUS

PDF

72.4 KB Created: 2021-04-11 11:44:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: e8309ab46fc5091198d0d13a24f89f37 SHA-1: b8d668a3f59804fbc3ef30f6a71406e6593c36d5 SHA-256: 19d75aefcc6bc54183933df0434927e5b5836a88b82250ebcc3dc737b15feaf2
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. It contains numerous embedded URLs, many of which point to suspicious or unknown domains, suggesting an attempt to redirect users to malicious sites. The document body, though heavily obfuscated, contains references to 'Hsu research stf 1' and 'wkhtmltopdf', indicating it may be part of a lure to disguise malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.visitsavannah.com/sites/default/files/webform/fukixuliwidopisoduzurapi.pdf In PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/niroxopewesanusogub.pdfIn PDF document text
    • https://europa-ts.ru/sites/default/files/webform/81905598419.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/22206840813.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/jedirokadezat.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/ginigiwosumomigari.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/gurolaxi.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/monufugabezexi.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/topijetidilotifoga.pdfIn PDF document text
    • http://spotlight-sites.com/sites/default/files/webform/jalipoxelelikepobolid.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/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=hsu+research+stf+1PDF link annotation
    • https://drones.princeton.edu/system/files/webform/xakunowegetudirojevogejiw.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/67925993666.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/18758627140.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/86005813007.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/xapedejezorim.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_off0000ddb4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDB4 4948 bytes
SHA-256: 753c7e678f69651166de26537df51bb6c66b3329817091f308e0301f35368945
font_01_sfnt_off0000ee85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE85 10872 bytes
SHA-256: 55bdc05cea32b6aaffd5caf1e1e0409a5cb3cfdb823a272326f32371b261d34a

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