Malicious PDF — malware analysis report

Static analysis result for SHA-256 9b571d808f281155…

MALICIOUS

PDF

143.2 KB Created: 2021-04-07 07:41:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: b6e41cbce33ac9ead061d572f538a50f SHA-1: d39ccf2cf1744f4a04f8ba9b6739ef9c7123a827 SHA-256: 9b571d808f28115597ddfbd61f857f0d3e14fe7bbb1271ebdd5401b6d759b10a
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to disposable domains, and is flagged by ML classifiers and ClamAV as malicious. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a likely attempt to create a link farm for SEO manipulation or to host malicious content. While no scripts were explicitly extracted, the presence of external URIs and the overall structure suggest it's designed to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9984

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://ambrose.edu/sites/default/files/webform/61928937085.pdf In PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/61943826361.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/55418097166.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/16831560309.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/19026354442.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/taxevoxasubosiwugudabi.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/99368311749.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/bipaxuvimul.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
    • http://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=indian+medicinal+plants+and+their+uses+pdf+in+hindiPDF link annotation
    • https://www.vub.be/sites/vub/files/webform/piwolumubixu.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/dilitopuwivane.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_off0001e507.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1E507 5104 bytes
SHA-256: 031b254df621bfdbeb5310f3c0eb541984f7e547402611540049bc1e397ec89a
font_01_sfnt_off0001f625.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1F625 14100 bytes
SHA-256: 304c9a6438897c5c2422a8352e274845ff141c922bb47b2692bc94e1844287c8
font_02_sfnt_off0002210d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2210D 4324 bytes
SHA-256: b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c

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