Malicious PDF — malware analysis report

Static analysis result for SHA-256 7b5720860cb23c70…

MALICIOUS

PDF

33.7 KB Created: 2020-06-03 08:07:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-09-24
MD5: 2bd366440b93a8e0e21e89bb2cde0d89 SHA-1: 7bf8046e84788f99c6ee2917bd62fed78f780a4a SHA-256: 7b5720860cb23c70c19bf178fdde508fa44c10874252ebca84a263f46f98e6b7
96 Risk Score

Malware Insights

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

The PDF document contains a large number of external links, many of which point to other PDF files hosted on similar domains. This behavior is indicative of a link farm or a mechanism to distribute malicious content indirectly. While no scripts were explicitly extracted, the PDF structure and the ML classifier's high confidence suggest malicious intent, likely related to SEO manipulation or hosting further stages of an attack. The presence of embedded URLs and the PDF_SEO_LINK_FARM heuristic strongly support this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

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://41z.undesirable.us/uploads/1/3/1/3/131398045/131398045.html#northwestern+mutual+internship+interview PDF link annotation
    • http://achievewithmv.com/uploads/1/3/0/7/130738979/vakufopoguzuref.pdfIn PDF document text
    • http://meiliphotography.com/uploads/1/3/1/4/131437677/e0f4772fd62ee3.pdfIn PDF document text
    • http://teenaceclothing.com/uploads/1/3/0/7/130775752/3553658.pdfIn PDF document text
    • http://acmbuenosaires.org/uploads/1/3/0/3/130324063/0cbfa.pdfIn PDF document text
    • http://startmeuptribute.com/uploads/1/3/0/7/130740596/b2488dba31b1e86.pdfIn PDF document text
    • http://browntmt.com/uploads/1/3/0/2/130273740/353b66af6a.pdfIn PDF document text
    • http://41z.undesirable.us/uploads/1/3/1/3/131398045/terms.htmlIn PDF document text
    • http://41z.undesirable.us/uploads/1/3/1/3/131398045/dmca.htmlIn PDF document text
    • http://41z.undesirable.us/uploads/1/3/1/3/131398045/policy.htmlIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://ramisiwew.files.wordpress.com/2020/05/mimepukanunoge.pdfIn PDF document text
    • https://kiwekesumi.files.wordpress.com/2020/06/70359045149.pdfIn PDF document text
    • https://wevamuxugivi.files.wordpress.com/2020/05/61348676340.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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000057dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x57DD 10388 bytes
SHA-256: 416755f08c2df5f86c0172d707b5047999b12ae042d9403517cc1faf02181a1a