Malicious PDF — malware analysis report

Static analysis result for SHA-256 85c98bff58cfd99a…

MALICIOUS

PDF

76.5 KB Created: 2021-04-11 04:20:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-26
MD5: 84107bbd5a4a9a67fb0aabc32f50ee10 SHA-1: f0b6e9fa12fa4a790e73013ba26c7ac059742b63 SHA-256: 85c98bff58cfd99a96c15616dcee2a3dc1db5ad5716a979ab7469708569b5295
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 a large number of embedded URLs, many of which point to suspicious or unknown domains, suggesting a link farm or phishing lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating the document is designed to host many links on potentially disposable domains. No scripts were extracted, but the overall structure and heuristics point towards a phishing or malware distribution attempt.

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 http://www.pbttphtk.gov.my/sites/default/files/webform/88462653206.pdf In PDF document text
    • https://www.dgs-interparts.be/sites/default/files/41094691834.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/30106672217.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/vogelunejubujapezidugave.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/kokibilelage.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/32056102714.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/54125375098.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/14219433733.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/71048230710.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/7838369457.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/41850888982.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/dekif.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/gewematumupam.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/64296936159.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/vopezupudatirarib.pdfIn PDF document text
    • https://www.mainephilanthropy.org/sites/default/files/guvobirewuge.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/GLLx1DTH0VQ/uplcv?utm_term=yellow+bullet+pills+amazonPDF link annotation
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/wutiladerotegedubel.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_off0000ee68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE68 5112 bytes
SHA-256: 11599b08079351a33b7986e3dc53cd6e74f155dc9571e3ea4c4d9b14c18a6f1d
font_01_sfnt_off0000ffd6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFD6 10924 bytes
SHA-256: 989e09a354410cd6d32c33fc30898eeb74c2952f2a5675f1cdc838e73469f7ea

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