Malicious PDF — malware analysis report

Static analysis result for SHA-256 66bc31adc8e2326e…

MALICIOUS

PDF

77.3 KB Created: 2021-03-17 01:19:33 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: fde19ca4d6eb484036a0a239ce752f28 SHA-1: d6c6e6806e0a65b1190ab6181c4726d56c939ca9 SHA-256: 66bc31adc8e2326eb66af2a26485d051328f0d130ff7465b3076ac510036e392
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, with a primary URL pointing to a suspicious domain that appears to be part of a link farm designed to redirect users. The document body, though heavily obfuscated, suggests a lure related to biological terms, likely to trick users into clicking the malicious link. No scripts were extracted, but the PDF structure and URL analysis strongly suggest a phishing or redirection attack.

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 https://gimoguvi.ru/strik?utm_term=what+are+long+strands+of+dna+that+contain+lots+of+genes+called PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4454807/normal_5fd973b85d638.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4386094/normal_6000c330ecf27.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4448995/normal_602778be5294b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413126/normal_5fd78af9860b2.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4417827/normal_5ffe632a5a304.pdfIn PDF document text
    • http://farexirofabi.22web.org/bter_application_form_2019.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4472760/normal_5fd8e296777c2.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4374376/normal_5feb95c6745b0.pdfIn PDF document text
    • http://nuzoxej.iblogger.org/inspector_lewis_2010_episode_guide.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4385231/normal_60503f02b576c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4499629/normal_6045f551e9ecb.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://xuvunemomot.epizy.com/12315458890.pdfIn PDF document text
    • http://parorusoba.rf.gd/venazewunopefe.pdfIn PDF document text
    • http://norilonabu.epizy.com/47611282880.pdfIn PDF document text
    • https://s3.amazonaws.com/devuxuzejozam/ayo_and_teo_reverse_instrumental.pdfIn PDF document text
    • https://s3.amazonaws.com/retobifulipo/brick_breaker_free_for_pc.pdfIn PDF document text
    • https://s3.amazonaws.com/kiwopusafize/nafaviwubenibaropabu.pdfIn PDF document text
    • http://xadogugatu.epizy.com/inorganic_chemistry_notes_for_bsc_1st_year.pdfIn PDF document text
    • https://s3.amazonaws.com/fovezewi/ansible_template_variable_name.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_off0000f118.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF118 5296 bytes
SHA-256: 6843401c69dab49882d42c2922340cc68b230db3440427570a5cd71c10e79f8f
font_01_sfnt_off00010326.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10326 10588 bytes
SHA-256: cfb0944f12ded39cb607d7575e32286f0ad72aa54725fd0b116e99d64343f875

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