Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d27285805d6f1c1…

MALICIOUS

PDF

70.4 KB Created: 2021-04-27 10:17:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 36a2efea36c39f1a55ba86b966455cb4 SHA-1: 7f792580a994a264f21de865aecc69f68cf0e93b SHA-256: 4d27285805d6f1c122ddd88c3b74fb2d63b7a65888a0e0dac741a86c0f005ee0
66 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The ML classifier strongly indicated maliciousness, and the presence of external URIs and a link farm heuristic further supports this. While no scripts were directly extracted, the structure and embedded links are indicative of a malware distribution attempt, likely using a spearphishing attachment as the initial vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 4

  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://oaklandchildcare.org/sites/default/files/webform/zomosazufexebale.pdf In PDF document text
    • http://spotlight-sites.com/sites/default/files/webform/44923699615.pdfIn PDF document text
    • https://europa-ts.ru/sites/default/files/webform/totikejeropisatuzubafaba.pdfIn PDF document text
    • https://www.newburghgroup.com/sites/default/files/webform/resumes/falaburisidibiwad.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/balulata.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/89382212171.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/tatemomolefifepa.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/bekam.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/juremetepatofuf.pdfIn PDF document text
    • https://www.visitsavannah.com/sites/default/files/webform/nodarinit.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=human+diseases+a+systemic+approach+8th+edition+pdf+downloadPDF link annotation
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/50075528518.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/83401752781.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/zupedofijemurak.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d552.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD552 5744 bytes
SHA-256: 4f2905ed4915ea5ebb081ae88d5ca8ec9ebd7d436c91361c0b5f6915b9370efb
font_01_sfnt_off0000e8cc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8CC 10380 bytes
SHA-256: b44e0b8c050b1a5690089695bf58da5347cb07e0a885a66f21b737d7fb0810f7

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