Malicious PDF — malware analysis report

Static analysis result for SHA-256 31579703c107ced1…

MALICIOUS

PDF

82.7 KB Created: 2021-04-23 23:26:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 4029ce805a5ba9b3a15e676b368f9293 SHA-1: 2e9cb5cd82fd4925c26fe686aa6767cfe828bbb6 SHA-256: 31579703c107ced142197831fd6079fdea03f00368dc5e853897ae5663e138c1
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which point to other PDFs, indicating a link farm or redirection scheme. The primary URL, https://kuzutuzo.ru/strik, is likely part of this malicious infrastructure. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • 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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://kuzutuzo.ru/strik?utm_term=discussion+topics+for+virtual+meetings
    • https://static.s123-cdn-static.com/uploads/4458145/normal_5fcf88b352e06.pdf
    • https://cdn-cms.f-static.net/uploads/4454043/normal_6060a884b0910.pdf
    • https://penogefuf.weebly.com/uploads/1/3/2/7/132740618/ropomezimifok_bimalurovog.pdf
    • http://ryukzak.digital/229813985959nm0e.pdf
    • http://carinsusa.info/spectrum_math_workbook_grade_8_free92cvz.pdf
    • https://jerejadudet.weebly.com/uploads/1/3/0/7/130738914/fazemimekig.pdf
    • http://idealica-official-it.website/86932499638kaoof.pdf
    • https://nodizolubuta.weebly.com/uploads/1/3/5/2/135297944/c7cb3f.pdf
    • http://graatorama.fun/toastmasters_table_topic_ideas56f2g.pdf
    • https://static.s123-cdn-static.com/uploads/4424672/normal_5fd03b6c87666.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/jevopemosod/50857149424.pdf
    • https://s3.amazonaws.com/sinadi/philippine_agenda_21.pdf
    • https://s3.amazonaws.com/batiku/darth_vader_theme_sheet_music_tuba.pdf
    • https://s3.amazonaws.com/bejenosugede/13727196319.pdf
    • https://s3.amazonaws.com/lazolu/premiere_pro_free_effects_plugins.pdf
    • https://s3.amazonaws.com/gadumagabusodel/cymera_old_version_apk.pdf
    • https://s3.amazonaws.com/tikofaketonub/86166561027.pdf
    • https://s3.amazonaws.com/gazitif/60500239361.pdf
    • https://s3.amazonaws.com/nagev/feline_asthma_treatment_guidelines.pdf
    • https://s3.amazonaws.com/midaguvimabof/rixisawokaxa.pdf
    • https://s3.amazonaws.com/loranoduzuja/dias_feriados_en_enero_del_2020.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f9eb.bin
8008f68d1dff63c1da013f8db6ddf05cccbe1bfd8f250a0aef0e9e080a08232f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF9EB 5396 bytes
font_01_sfnt_off00010c3c.bin
171062da004556aaa5bf672d54ad6b3e94fc8aba1f78f41c7381c20b9151de43		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10C3C 1920 bytes
font_02_sfnt_off00011561.bin
6eda052a3f4bf7e5afa1f3eca2ee286fa5413e03f89eec058a2518ee87aa00b1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11561 11224 bytes

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