Malicious PDF — malware analysis report

Static analysis result for SHA-256 83ab2399bcbd9a06…

MALICIOUS

PDF

67.1 KB Created: 2021-04-24 20:37:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 8591eebfb0b864443c2dfeecd1a01191 SHA-1: e407c0dd4409d73c81053d46a7a6204d8fa42aec SHA-256: 83ab2399bcbd9a06842d2545f6fecbda0d6e95b8c39b53b5da7e517c6990d935
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to potentially compromised academic or organizational websites, suggesting a link farm or phishing lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a deliberate attempt to obscure the true destination or host a large number of links. While no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with phishing or malware distribution campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://ambrose.edu/sites/default/files/webform/28961662769.pdf In PDF document text
    • https://www.mainephilanthropy.org/sites/default/files/79141676299.pdfIn PDF document text
    • http://www.pacificsportfraservalley.com/sites/default/files/webform/zajufofagobixipisuna.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/32041770382.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/doxuwekuwazomiloxeri.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/49428740932.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/28695523124.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/35039450578.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/topevonizudurazot.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/95147346690.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/mibotemesasis.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/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=active+and+passive+voice+worksheet+class+10PDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/21338807989.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/47045932069.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/wosevojowavinojefe.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_off0000caff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCAFF 5560 bytes
SHA-256: e686e6738a7cde8d08abbf2625aca18695d9574c63c0dcdec4d227bf1acbabc9
font_01_sfnt_off0000ddfe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDFE 9864 bytes
SHA-256: 09cf075fe66ff7be5fe1327cf28240843d7660c99ef3e76b4182d9c4a3f26e80

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