Malicious PDF — malware analysis report

Static analysis result for SHA-256 43bb86fd9e41e408…

MALICIOUS

PDF

47.9 KB Created: 2020-03-08 03:04:11 +02:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6)
MD5: f5056a30dcd80a33b1b7401f8fb65b23 SHA-1: 890029a261ddf3cc55f88af2155ff7b2fae9ba5d SHA-256: 43bb86fd9e41e40888e02cb052a63c4ce2af4346435da44aef57bb8e2e532202
94 Risk Score

Malware Insights

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

The PDF document contains a large number of embedded external links, identified by the PDF_SEO_LINK_FARM heuristic. The document body, though partially corrupted, contains Portuguese text related to grammar exercises and references the wkhtmltopdf tool, suggesting a lure. The primary attack pattern involves directing users to a vast array of linked PDF files hosted on numerous domains, likely for SEO poisoning or to distribute further malicious content. No scripts were extracted, limiting the analysis of direct payload execution.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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://teamgls.com/uploads/1/3/0/5/130589078/130589078.html#exercicios+de+adjunto+adnominal+e+adverbial+com+respostas
    • http://eig21.com/uploads/1/3/0/5/130590689/8598388.pdf
    • http://adriftwoodworks.com/uploads/1/3/0/4/130488539/vefutoj.pdf
    • http://katrinadasilvaart.com/uploads/1/3/0/5/130542692/nexugovorun.pdf
    • http://smokyrex.com/uploads/1/3/0/4/130489075/87d08ab.pdf
    • http://ncrage.com/uploads/1/3/0/3/130379361/wukorukegom.pdf
    • http://airinbudiman.com/uploads/1/3/0/6/130621856/c9a9bfbb83439.pdf
    • http://nqfd.com.au/uploads/1/3/0/4/130476678/puviveligij_sijuvemuruw_sexuxamej_zanid.pdf
    • http://oreginconference.com/uploads/1/3/0/5/130551187/mirijedupebi.pdf
    • http://instartcorp.com/uploads/1/3/0/4/130483243/genipibab.pdf
    • http://www.kristenlavigne.com/uploads/1/3/0/3/130379412/bopitex.pdf
    • http://lukassivak.com/uploads/1/3/0/3/130379063/fde4d64b2.pdf
    • http://extperformance.com/uploads/1/3/0/3/130323900/67c65c0ad38cb5c.pdf
    • http://kimberlylopezportfolio.com/uploads/1/3/0/7/130739192/retob.pdf
    • http://koncgroup.com/uploads/1/3/0/4/130488749/72b9ab4616f6426.pdf
    • http://redalbury.com.au/uploads/1/3/0/7/130775918/0c17a621ebe.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_off00008e98.bin
5579bf2c925d8d04150478290b9bfe309d1a21b666e9f90a01b599745266a0bc		 pdf-font-stream PDF embedded font (sfnt) at offset 0x8E98 10204 bytes

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