Malicious PDF — malware analysis report

Static analysis result for SHA-256 73b341a75c1d7739…

MALICIOUS

PDF

89.3 KB Created: 2021-01-30 03:25:19 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: fd5d728ed3ebae0d389c5f0e44ce28e2 SHA-1: 2948963db7436f543affa5309428fbc8a4ac47f8 SHA-256: 73b341a75c1d7739e01e0dfa58cd56ecf2b50472de04143807b97f47bfb55b06
96 Risk Score

Malware Insights

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

The PDF file contains a heuristic firing for a 'PDF_SEO_LINK_FARM', indicating a large number of external links, with one prominent example being https://s3.amazonaws.com/nawuvud/84186006280.pdf. The 'PDF_URI' heuristic also identified https://seumenha.ru/123?utm_term=c4+vs+c3. The ML classifier strongly flagged this PDF as malicious. While no scripts were explicitly extracted, the structure suggests an attempt to redirect users to potentially harmful content, aligning with spearphishing attachment tactics.

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 https://seumenha.ru/123?utm_term=c4+vs+c3 PDF link annotation
    • https://webapifupa.weebly.com/uploads/1/3/4/7/134706955/bd08340853c72.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4383679/normal_5fdb29972c1ab.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4404727/normal_5ffd0702c97de.pdfIn PDF document text
    • https://worijuxadije.weebly.com/uploads/1/3/4/8/134863955/4477993.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4426425/normal_5fd02c2eb7459.pdfIn PDF document text
    • https://wezobugedelu.weebly.com/uploads/1/3/1/8/131856743/wemafajijinefu.pdfIn PDF document text
    • https://sabopedawexidix.weebly.com/uploads/1/3/4/3/134305122/9f98fa53.pdfIn PDF document text
    • https://kuzipefosorus.weebly.com/uploads/1/3/4/6/134687186/runanodomuber-dajidekisipefu-tawokar-nerojinipokis.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/nawuvud/84186006280.pdfIn PDF document text
    • https://s3.amazonaws.com/xonobijikivo/hypertension_2018_guidelines.pdfIn PDF document text
    • http://vizepojuduw.rf.gd/embriologia_de_la_piel_y_anexos.pdfIn PDF document text
    • https://s3.amazonaws.com/nalifij/gate_2018_instrumentation_books_free.pdfIn PDF document text
    • https://s3.amazonaws.com/jofunozuzof/12022924595.pdfIn PDF document text
    • https://s3.amazonaws.com/pululusodogi/6273192505.pdfIn PDF document text
    • https://s3.amazonaws.com/lokijuronig/sagojod.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ff6e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF6E 4672 bytes
SHA-256: 0b553f7cbea917051d5676b3ec1e93e4b993ac0a062dca51899be9772f749e63
font_01_sfnt_off00010f7a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F7A 15992 bytes
SHA-256: cd46396e8e3d4a58bab58e803fa2ccd3c49a4e9600810a5175934a1173f6e0a6
font_02_sfnt_off00014127.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14127 16204 bytes
SHA-256: 31aa257675234f953cb39254c73a0c002637764ec2691c470e0912636c3685cf

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