Malicious PDF — malware analysis report

Static analysis result for SHA-256 836b394d2c4d9cec…

MALICIOUS

PDF

101.6 KB Created: 2021-04-26 00:08:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: bb83226ead6c582a0b9ee5c02f754e9f SHA-1: de320a7475c82cc9523b172e3f6caf29dceedd1d SHA-256: 836b394d2c4d9cec7e14f133ad15f3c2fef96950f87c73e25798db0bce7b449e
186 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including ClamAV and an ML classifier. It contains a large number of external links, many hosted on disposable domains, suggesting a link farm or SEO manipulation tactic. One URL, https://nipisod.ru/strik?utm_term=simple+world+history+timeline+pdf, appears to be a redirector. While no scripts were explicitly extracted, the PDF structure and link farm behavior are indicative of malicious intent, potentially to distribute further malware or conduct phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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://nipisod.ru/strik?utm_term=simple+world+history+timeline+pdf PDF link annotation
    • http://nubigawe.22web.org/hutchison_whampoa_properties_limited_annual_report.pdfIn PDF document text
    • http://vukufitu.mywebcommunity.org/kepad.pdfIn PDF document text
    • https://bawezinanowele.weebly.com/uploads/1/3/4/3/134305895/lesaweni_kabepofekisur.pdfIn PDF document text
    • https://fulopovesaj.weebly.com/uploads/1/3/0/7/130740112/9174b2.pdfIn PDF document text
    • https://tokafiwunan.weebly.com/uploads/1/3/4/3/134372509/6828723.pdfIn PDF document text
    • https://gakikodokuni.weebly.com/uploads/1/3/1/8/131857060/xokitapurini.pdfIn PDF document text
    • https://dirogine.weebly.com/uploads/1/3/0/7/130775503/rasomusatazuf_lasubim_jidaj.pdfIn PDF document text
    • https://favipipuwebex.weebly.com/uploads/1/3/5/3/135397367/f7986.pdfIn PDF document text
    • http://mezajozugabaso.getenjoyment.net/8849632132.pdfIn PDF document text
    • https://wuwebiwurumebil.weebly.com/uploads/1/3/1/1/131164488/runirok_rimodu_tudipa.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/xojafemori/chemnitz_weather_report.pdfIn PDF document text
    • http://sozejegisiwex.epizy.com/bofudozokurexazogumog.pdfIn PDF document text
    • http://luvafavuma.rf.gd/the_abc_s_of_bauhaus_the_bauhaus_and_design_theory.pdfIn PDF document text
    • https://s3.amazonaws.com/paropabaru/converting_length_worksheet_year_6.pdfIn PDF document text
    • http://pisumapopub.rf.gd/adini_sen_koy_episode_70.pdfIn PDF document text
    • http://jitawidavez.atwebpages.com/libro_los_grandes_economistas.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_off00014ec3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14EC3 5368 bytes
SHA-256: 2bca01380ca10887ea8460788d4179ad2e1794e44a5c499af8366bf7d47e5e50
font_01_sfnt_off000160f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x160F0 12004 bytes
SHA-256: 3d98a9837082ce9cf9a566a21b1dbd070d8ef9d70c9a47b5c0f7cef8542a2e6e

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