Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f388156b379c42f…

MALICIOUS

PDF

80.6 KB Created: 2021-04-08 21:30:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 5d6a01e0346ce8cc0b7c34a7277033a8 SHA-1: 1c28f5bfc39ed75e999127e3e2a151961943099a SHA-256: 4f388156b379c42f7365f219e42293b255f3146df20784c8d969a16cce5905ea
126 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a high-confidence ML classifier and ClamAV detection as a phishing trojan. It contains numerous embedded URLs, many of which point to disposable hosting or unknown domains, suggesting a link farm or redirection scheme. The document body, though heavily obfuscated, contains references to 'Princeton review cracking the act pdf', which is likely a lure to attract victims. No scripts were extracted, but the presence of many external links indicates an attempt to redirect users to malicious content.

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://klm3fg.grhosting.cz/sites/default/files/webform/files/todoxobolukajit.pdf In PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/xugapovapoz.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/61975266633.pdfIn PDF document text
    • http://russian-ice-spb.ru/sites/default/files/webform/files/zatepatepekaberemosigedix.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/zuloliresu.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/99368311749.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/6669476875.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/nutuzisujobipusife.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/77861868930.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/tarutemivejumariwara.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/40041164747.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/futexapepunuvanujom.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/42535902170.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/48103714077.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/xufatonapa.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=princeton+review+cracking+the+act+pdfPDF link annotation
    • https://drones.princeton.edu/system/files/webform/zifogisabivaloxigisosobu.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/wetesagepe.pdfIn PDF document text
    • https://umatter.princeton.edu/system/files/webform/requests/72435273025.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_off0000fd5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD5E 5424 bytes
SHA-256: 84b39b035a64e48124c6d3ac8eb4d050e3a176460141c9cbe448ec02ea4a220b
font_01_sfnt_off00010fe8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10FE8 11056 bytes
SHA-256: 1599868c4625771378a074ec4500c429c1160a1a588ea7c58e00143d99280f12

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