Malicious PDF — malware analysis report

Static analysis result for SHA-256 4daa3b6cafd57c34…

MALICIOUS

PDF

88.4 KB Created: 2021-04-11 05:23:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-30
MD5: ba2545a75a252e264be95015b06c03dc SHA-1: 9bd03f71ad040fb5b2b58402cee09e81762f0a96 SHA-256: 4daa3b6cafd57c34b301c505fcf7a4e48b3c70a6fc75c64b9c46f1c5deaa0774
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The file was detected as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to potentially malicious domains. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create PDFs from web content, further supporting the link farm hypothesis.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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.enwidth.com/sites/default/files/webform/resumes/17232120942.pdf In PDF document text
    • https://www.jsif.org/sites/default/files/webform/meratasadif.pdfIn PDF document text
    • http://spotlight-sites.com/sites/default/files/webform/sugugijokasu.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/ginigiwosumomigari.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/68038126183.pdfIn PDF document text
    • https://europa-ts.ru/sites/default/files/webform/81905598419.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/tajiwugebewozebukak.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/zarogoluvesiriwameb.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=datt+bavani+pdfPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/zixulupuritijidegebi.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/27560642257.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/jojilekavoxojomoz.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000113d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113D0 4488 bytes
SHA-256: 5a772074c28e1bbe682f49c0fb3c93073bd748ab89254830fd029586143b0cc9
font_01_sfnt_off00012315.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12315 10948 bytes
SHA-256: 01b819bc41ccd9439968fde080111d7689cab8f9272f41a43f8536e9f44f58f8
font_02_sfnt_off00014863.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14863 4324 bytes
SHA-256: cd94ef65598b1866d0653cdd88243d989fd81359c0e770c2d3a4858f1c2f6d34

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