Malicious PDF — malware analysis report

Static analysis result for SHA-256 623d441d524767dc…

MALICIOUS

PDF

79.2 KB Created: 2021-06-03 00:03:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 81a58a6c60fc8284dd36e6a676be1c62 SHA-1: 76f6564756e92d1d50a473a728fadf849895fc74 SHA-256: 623d441d524767dcf5dd66c6c64bbc2e774b8bc2f18ef51fb010afe9bd25dd47
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan payload. It contains a large number of external links, many pointing to other PDF files hosted on disposable domains, suggesting a link farm or SEO manipulation tactic. The primary malicious URL identified is https://laborke.ru/pbw?utm_term=ap+literature+multiple+choice+practice+test+with+answers+pdf.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://laborke.ru/pbw?utm_term=ap+literature+multiple+choice+practice+test+with+answers+pdf PDF link annotation
    • https://newajijamo.weebly.com/uploads/1/3/4/7/134750143/4a46c74.pdfIn PDF document text
    • https://rikovikoxeko.weebly.com/uploads/1/3/2/7/132740842/tutebo_zokujutoxuf_kesudurokinobo.pdfIn PDF document text
    • https://lolivifi.weebly.com/uploads/1/3/0/7/130739590/db301ad87.pdfIn PDF document text
    • https://folumenudi.weebly.com/uploads/1/3/2/6/132681426/2895820.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4382958/normal_6010f02a42d2b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4384470/normal_6015d57fe46ed.pdfIn PDF document text
    • https://mitemulesebiped.weebly.com/uploads/1/3/4/4/134479511/dorifefeg-kikadut.pdfIn PDF document text
    • https://fufobulevuzim.weebly.com/uploads/1/3/4/6/134650144/9442645.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4490930/normal_6056a7a2f3638.pdfIn PDF document text
    • https://zufuzoxosuf.weebly.com/uploads/1/3/4/5/134500743/wonukamu.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://mumubib.pbworks.com/f/14485633926.pdfIn PDF document text
    • http://fodorafirig.pbworks.com/f/mawedawakufuvisale.pdfIn PDF document text
    • http://zelovoguvunu.pbworks.com/w/file/fetch/144426939/73696835207.pdfIn PDF document text
    • http://xovelezid.pbworks.com/w/file/fetch/144415719/descargar_gta_sa_para_android_lite.pdfIn PDF document text
    • http://mapaduzipi.pbworks.com/w/file/fetch/144528813/what_is_the_procedure_in_disassembling_and_assembling_an_electric_motor.pdfIn PDF document text
    • http://supatibu.pbworks.com/w/file/fetch/144419010/27879674071.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_off0000f500.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF500 5476 bytes
SHA-256: cff69a7871516dbe0f042e603115b5f3cab0ce425e8d4a8fda00e4b4620b1624
font_01_sfnt_off00010785.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10785 11256 bytes
SHA-256: e45a44f9b4a0604448eb1d47f12f4bd67126a803f9dfad99a20995f36b1d0907

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