Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b7553e53cd3cb5f…

MALICIOUS

PDF

35.9 KB Created: 2020-06-04 20:18:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: a540759c7c66a5b21279a6faa33be332 SHA-1: 46286dc85d3bbb25ab2aac24be61208a4006bc77 SHA-256: 5b7553e53cd3cb5ffa9f4deb00b45a9825f0506c57508902102073c40a2e4552
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded external links, identified by the PDF_SEO_LINK_FARM heuristic. The document body, though partially corrupted, contains text related to 'Problemas razonados de reparto para segundo de primaria' and includes URLs that appear to be part of a link farm. The ML classifier also strongly indicated maliciousness. The primary attack pattern involves directing users to a multitude of external PDF files, likely for SEO spam or to host further malicious content.

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://appcitygames.nl/uploads/1/3/0/2/130270826/130270826.html#problemas+razonados+de+reparto+para+segundo+de+primaria
    • http://multitechnrj.net/uploads/1/3/1/3/131380021/26cd2ad2.pdf
    • http://form-1099-c.com/uploads/1/3/0/6/130604018/fuxuzizujofati.pdf
    • http://peekaboo-tique.biz/uploads/1/3/0/8/130874530/migudojubuvu.pdf
    • http://goliveyachts.com/uploads/1/3/0/6/130639374/8998349.pdf
    • http://weloveamericasheros.org/uploads/1/3/0/3/130323415/xokipa.pdf
    • http://thepeacefulmarket.com/uploads/1/3/0/5/130590438/mavuxujapuno.pdf
    • http://appcitygames.nl/uploads/1/3/0/2/130270826/terms.html
    • http://appcitygames.nl/uploads/1/3/0/2/130270826/dmca.html
    • http://appcitygames.nl/uploads/1/3/0/2/130270826/policy.html
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://mewukajiz735874670.files.wordpress.com/2020/06/69460440604.pdf
    • https://zarupuzagi.files.wordpress.com/2020/06/davujuga.pdf
    • https://suruxux.files.wordpress.com/2020/06/nedonazejofesirirugoxeb.pdf
    • https://wikukan666946454.files.wordpress.com/2020/06/bominixuja.pdf
    • https://relopupuxa.files.wordpress.com/2020/06/9039470091.pdf
    • https://puroditaduj70542517.files.wordpress.com/2020/06/51014507640.pdf
    • https://wekujepomope.files.wordpress.com/2020/06/22516763575.pdf
    • https://silopesazov433664634.files.wordpress.com/2020/06/84738670747.pdf
    • https://duvisigu.files.wordpress.com/2020/06/negufedavetesilugi.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/
    • http://scripts.sil.org/OFL

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005d9b.bin
63ea0a9b37c233a35ed68f69f9596d8aa979c3df0aa4d0427ad0103ed448c2ed
pdf-font-stream PDF embedded font (sfnt) at offset 0x5D9B 11056 bytes