Malicious PDF — malware analysis report

Static analysis result for SHA-256 dec52f3c9e519011…

MALICIOUS

PDF

69.0 KB Created: 2021-04-07 14:59:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: e05c82c3992de08378d4b21fb9916ac9 SHA-1: 2568edcd061b06fa25d1c843134876fa7798943a SHA-256: dec52f3c9e5190110f9edd9ebb5686e29596974d8981d05885a0a1c4db4aed04
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to seemingly legitimate domains but are structured to host PDF files, suggesting a link farm or redirection mechanism. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for link farms, a common tactic in phishing campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://oaklandchildcare.org/sites/default/files/webform/85278691340.pdf In PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/kuvusuwube.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/tajiwugebewozebukak.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/nufideleze.pdfIn PDF document text
    • https://www.visitsavannah.com/sites/default/files/webform/71260674720.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/geguridafaj.pdfIn PDF document text
    • https://www.newburghgroup.com/sites/default/files/webform/resumes/woxofenobe.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/69774832497.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/setafemamuf.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/70037852461.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=suffix+worksheets+for+grade+2+pdfPDF link annotation
    • https://gradfutures.princeton.edu/system/files/webform/pelafo.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/31460711967.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/xapedejezorim.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_off0000cfd4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFD4 5732 bytes
SHA-256: 2b254279c67498bfc17878330b2d2478909bd138c324e32e2bc7448bec57257c
font_01_sfnt_off0000e370.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE370 10356 bytes
SHA-256: 74ca3225c8b10efa4f0a6c2924742cd2d48df28a4a3f5ee713e52c19899d74df

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