Malicious PDF — malware analysis report

Static analysis result for SHA-256 85b0ad8b5d38ec76…

MALICIOUS

PDF

68.1 KB Created: 2020-12-19 16:13:54 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 4deac17d6691679cdcc2036cd004d090 SHA-1: 2ebdc37ff4c074c692a2155c84575ef350fd5d6f SHA-256: 85b0ad8b5d38ec76727382715e5a6e2c7da991efc0d748f3b32403ee3201bb73
244 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many of which point to disposable hosting or known malicious redirectors. The document body, though heavily obfuscated, suggests a lure related to educational materials. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or to serve a second-stage payload.

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://cctraff.ru/strik?utm_term=arithmetic+series+worksheet+with+answers In PDF document text
    • https://cdn-cms.f-static.net/uploads/4417137/normal_5fb7cee8d139f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366662/normal_5f9d7e719f47b.pdfIn PDF document text
    • https://jezilifubi.weebly.com/uploads/1/3/4/8/134887413/4f9d8336.pdfIn PDF document text
    • https://mofagobebaz.weebly.com/uploads/1/3/4/6/134633285/9581422.pdfIn PDF document text
    • https://bozadabeduli.weebly.com/uploads/1/3/4/8/134869561/fokofixepo-fopajuwanatinu.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4425224/normal_5fcc71af73f97.pdfIn PDF document text
    • https://xepajozojiv.weebly.com/uploads/1/3/4/4/134476610/nufev.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417145/normal_5fd9b3c67c268.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4367667/normal_5fd3ca4c14be9.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/mozirolinitaje/distilled_water_ffxiv.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/33c2a169-3a3d-4f27-9223-5bc25e90a088/runtheedge_2019_login.pdfIn PDF document text
    • https://s3.amazonaws.com/dibedamoka/capital_fm_playlist.pdfIn PDF document text
    • https://static1.squarespace.com/static/5fcec23c5ecf630459445b0a/t/5fd60d77ffab5d3c56f08f5d/1607863671250/chale_aana_whatsapp_status_full_screen.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/30f2233f-1d3e-4ca9-ad3d-910adcd03208/94115754605.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_off0000ca5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA5C 5152 bytes
SHA-256: ffaf2a91da68a80157cdf03c96e779bc7f1a04ddb0f33fdd077ead696f519746
font_01_sfnt_off0000dbc8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBC8 11748 bytes
SHA-256: d528a871dd5b27bb8e5f1d5444f44da55bf938f2e888cb7babb96087edb3795d

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