Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9b6c9d1dac81d0a…

MALICIOUS

PDF

66.2 KB Created: 2021-02-22 01:32:34 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: d00357547ba66cf9952560383ad9418d SHA-1: d90ed3539978e27d580c3a1be4e37c954f55316d SHA-256: b9b6c9d1dac81d0aaaf30d5cbaf27f2bf988ed6d9e77c5ef9f1bfb280b313385
126 Risk Score

Malware Insights

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

The sample is a PDF document flagged by multiple heuristics as malicious, including ML classification and ClamAV detection. It contains numerous embedded URLs, many pointing to disposable domains or link farms, suggesting a phishing or malware distribution attempt. The document body, though heavily obfuscated, contains references to 'rate your professor byui' and 'wkhtmltopdf', indicating a potential lure. The presence of external URIs and link farm heuristics strongly suggests the document's purpose is to redirect users to malicious websites.

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://jacksth.ru/wix?keyword=rate+your+professor+byui PDF link annotation
    • https://cdn.sqhk.co/kedilexele/hdMe7gc/oneplus_careers_chennai.pdfIn PDF document text
    • https://cdn.sqhk.co/labifikup/gij56jc/20493099504.pdfIn PDF document text
    • https://cdn.sqhk.co/nixivezez/chfYhag/red_balloon_bookshop_hours.pdfIn PDF document text
    • https://cdn.sqhk.co/zukuxenopo/uyZ09ha/horizons_fcu_routing_number.pdfIn PDF document text
    • http://rkconstructionsucks.com/vegojelisap0bgtg.pdfIn PDF document text
    • http://uspehdnyaaxyz.xyz/teredomcfv.pdfIn PDF document text
    • https://cdn.sqhk.co/pakebisas/igfhdie/nubaf.pdfIn PDF document text
    • https://cdn.sqhk.co/mixaluwekitu/03idida/boribizojosatekubuvewuzu.pdfIn PDF document text
    • http://kompledom.com/ca_state_disability_forms_onlinejpu5l.pdfIn PDF document text
    • https://cdn.sqhk.co/pirujezexod/wEMjfhh/wizilomesis.pdfIn PDF document text
    • http://study-english-02.space/harry_potter_movies_in_hindi_full_hd_downloadc517i.pdfIn PDF document text
    • http://beliyden.xyz/761925210040yert.pdfIn PDF document text
    • https://cdn.sqhk.co/kofosenolo/gdmhcgj/vukonezexikugewuvivedobo.pdfIn PDF document text
    • http://alisabor.design/31428335811griop.pdfIn PDF document text
    • https://cdn.sqhk.co/fopujetoros/1jjd41G/kajoxizuv.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/vukusa/92821256315.pdfIn PDF document text
    • https://s3.amazonaws.com/daselex/21451984721.pdfIn PDF document text
    • https://s3.amazonaws.com/bakoloj/50422722745.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_off0000c7ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7EE 5112 bytes
SHA-256: 897ec884c447dab4fd4fc87af957b9c07a925c75f6a6aafe207c620abc8bcb88
font_01_sfnt_off0000d96d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD96D 10120 bytes
SHA-256: 9df06d991094c221e39c0c02227b1c338893573dbf3e771e908e22fd7a1cf0e0

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