Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c3fb899b71f4d06…

MALICIOUS

PDF

43.4 KB Created: 2020-04-03 14:51:58 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6)
MD5: f73c95bb3ebb4a659f745743814f384a SHA-1: 737c2cfacdc44178a613293ffda74dd444bdfd4f SHA-256: 8c3fb899b71f4d063e1aef16c73635e01322bdae2558ef3d3ea18b90271e45c9
154 Risk Score

Malware Insights

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

The PDF contains a large number of embedded external links to other PDF files hosted on various domains. This behavior is indicative of a link farm, often used for SEO manipulation or to distribute further malicious content. The ClamAV detection and ML classifier strongly support its malicious nature. No scripts were extracted, but the primary attack pattern is the distribution of numerous external links.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Dropper.Agent-9202855-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-9202855-0
  • 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://antiquefest.org/uploads/1/3/1/3/131384403/131384403.html#resumen+teoria+objetiva+y+subjetiva+del+valor
    • http://phillysportspassion.com/uploads/1/3/0/7/130740143/pexiponafopenagubog.pdf
    • http://earhartcorporatecenter.com/uploads/1/3/0/4/130483307/803234.pdf
    • http://eightfooteleven.com/uploads/1/3/0/7/130739937/ganosebebikije.pdf
    • http://youngcelebrationsoflife.ca/uploads/1/3/0/6/130620700/xaroxuzo.pdf
    • http://alyssamariemovementaddict.com/uploads/1/3/0/6/130639409/lirad.pdf
    • http://kaleidoscope.photos/uploads/1/3/0/2/130270945/pomisopigul_rutogi.pdf
    • http://coloradoartclass.org/uploads/1/3/0/2/130271094/344a7708e71e827.pdf
    • http://authorjulietcarrera.com/uploads/1/3/0/6/130603997/6956355.pdf
    • http://navarrorachel.com/uploads/1/3/0/6/130620700/winixaja-kaxugimagotar-vabow-jejanozavitasu.pdf
    • http://pc-online-hub.com/uploads/1/3/0/2/130291822/5299130.pdf
    • http://enthrallthreshold.com/uploads/1/3/0/2/130289746/rinuwirasizefizawum.pdf
    • http://cds-ma.net/uploads/1/3/0/6/130640174/jusabereg_jugolu.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000759d.bin
dd5570340b04843320854c36c2093acf9a61ff2f2ff0bdf07879697bf59a0528		 pdf-font-stream PDF embedded font (sfnt) at offset 0x759D 8688 bytes
font_01_sfnt_off000094ca.bin
50224c6c483bfa86a10f62efd7baa2c756f8036c0a911ebd537387e21b2fb6f3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x94CA 2732 bytes

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