Malicious PDF — malware analysis report

Static analysis result for SHA-256 51d6bc9676de0f13…

MALICIOUS

PDF

68.7 KB Created: 2021-04-14 21:49:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: cdcb24d1c9246c8595b96b14abe1c53f SHA-1: bf549a28e060f5b9e6f5c9be1d5686894d24a938 SHA-256: 51d6bc9676de0f134e97f4848d87057a104331bd3787b884d1a29cb04b5c3bc8
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of embedded URLs, many of which point to unknown or potentially malicious domains, suggesting a link farm designed to redirect users to harmful content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true 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 http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/lozege.pdf In PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/tajiwugebewozebukak.pdfIn PDF document text
    • https://www.mainephilanthropy.org/sites/default/files/lipedoketuparukol.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/tizodakemepegipupimegoxi.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/larigujumikanezazezogiwi.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/9027254294.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/pugixenarewowu.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/29410319198.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/99368311749.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/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=gesti%25C3%25B3n+del+talento+humano%2528+3a.+ed.%2529PDF link annotation
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/72323592377.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/42179508969.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/janoruzafasolefixos.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_off0000cdeb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDEB 5484 bytes
SHA-256: f1e68081fee770edbc107502eeaf4144e5f091784c6679ec8689b72a7f9096ff
font_01_sfnt_off0000e03d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE03D 10940 bytes
SHA-256: 765dc2fed494be9a2adedb8e2e631412fc0eba765c3d8cfed039dd6c0b7ad249

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