Malicious PDF — malware analysis report

Static analysis result for SHA-256 f90c60256ca251e0…

MALICIOUS

PDF

31.3 KB Created: 2020-04-07 14:20:11 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6)
MD5: 27aa7916f16a86c137aab38db3438c5c SHA-1: 3467eba54deda88c6cea8cf78f96e0654051f5fa SHA-256: f90c60256ca251e0209fc9b6208460c678b47274ec9fdf10f09e4d9d201b375e
96 Risk Score

Malware Insights

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

The PDF file contains a significant number of external links, many of which point to domains that appear to be part of a link farm designed to artificially boost search engine rankings. The document body, though partially corrupted, contains a lure related to 'Imagenes de salud bucal para imprimir' and references the wkhtmltopdf tool, suggesting it was generated programmatically. The ML classifier strongly flagged this PDF as malicious, indicating a high probability of malicious intent behind the link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 4

  • 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.
  • 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://theclaytonconnection.com/uploads/1/3/0/2/130272573/130272573.html#imagenes+de+salud+bucal+para+imprimir
    • http://vtjcollabo.com/uploads/1/3/1/0/131070722/nadoxedovusuni.pdf
    • http://wdfilms.org/uploads/1/3/0/3/130313410/jifebotipo_davaxedupisoxo.pdf
    • http://colleeniesbeanies.com/uploads/1/3/1/4/131407892/xexifesatidati-zebenakeset-xoxam.pdf
    • http://ict4l.info/uploads/1/3/0/5/130540046/3d92e2a.pdf
    • http://tilecroftfarms.com/uploads/1/3/0/7/130776667/23edd527b5.pdf
    • http://omahamassagecoupons.com/uploads/1/3/0/5/130551198/lotutejineriwo-bilipivulabelef.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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000553b.bin
ba62c3c0b734c05f870be90d36c614b49a337280422a8856168db2eb79b6a834		 pdf-font-stream PDF embedded font (sfnt) at offset 0x553B 7312 bytes

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