Malicious PDF — malware analysis report

Static analysis result for SHA-256 87a8337ced6ab3a5…

MALICIOUS

PDF

77.2 KB Created: 2021-02-25 01:20:48 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: 470ba687f89edb589e32e3762f222327 SHA-1: f44a43f777fa534a7886b04d3234e6d8a4eef0ec SHA-256: 87a8337ced6ab3a59d41e7c10a9006f872e3b3d3239391683cb28e5c67c88cc8
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of external links, identified by the PDF_SEO_LINK_FARM heuristic, suggesting it's part of a link farm or SEO manipulation scheme. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution through the linked PDFs. The document body is heavily obfuscated and contains metadata related to its generation, but the primary malicious activity is the distribution of external links.

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://jacksth.ru/123?utm_term=grade+3+math+3d+shapes+worksheets PDF link annotation
    • http://requiredjokblog.com/arya_2_mp3_songs_download59908.pdfIn PDF document text
    • http://it50life.pro/207527547558xf43.pdfIn PDF document text
    • http://pycnidwzxc.info/475234152928o2n5.pdfIn PDF document text
    • https://cdn.sqhk.co/nulusezitelo/2PV9ijB/pemonanalagonajawi.pdfIn PDF document text
    • http://wildboost.club/98387961691gwk95.pdfIn PDF document text
    • https://cdn.sqhk.co/mujejadalale/gfnggZH/best_outdoor_cat_condo_for_large_cats.pdfIn PDF document text
    • http://ig-copyrighthelpcenter.com/795096203121z76b.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4388833/normal_5ff1338f61930.pdfIn PDF document text
    • https://rixemovupel.weebly.com/uploads/1/3/1/6/131606965/ea7dcf.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4369629/normal_5fedd04b6fdc3.pdfIn PDF document text
    • https://cdn.sqhk.co/noxomosanena/cn2Oie9/9493561604.pdfIn PDF document text
    • https://xereritotof.weebly.com/uploads/1/3/1/0/131070340/c4486c921f39.pdfIn PDF document text
    • http://sfhgfje5df.xyz/xuxunexerajudazojinomebemlfmy.pdfIn PDF document text
    • https://cdn.sqhk.co/vixawutozama/5ibgigi/59776344523.pdfIn PDF document text
    • http://meetraisins.club/converter_em_dwg_gratis_online1atzw.pdfIn PDF document text
    • https://nezozavigarej.weebly.com/uploads/1/3/4/7/134727028/6611043.pdfIn PDF document text
    • https://cdn.sqhk.co/rowofabuf/Beqibia/57233798248.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://s3.amazonaws.com/foneniz/kabupagaturog.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e512.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE512 5152 bytes
SHA-256: c27d14dd380b6fd20236cde13ddb3e16d3cc877d0a374c31908f4ec83e5dc206
font_01_sfnt_off0000f6b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6B4 10280 bytes
SHA-256: 001305aac00706fcd955c3fdeeb5f1b01ee46c26c3e0bc457d58fdbcce3e6a3f
font_02_sfnt_off000119ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119ED 4324 bytes
SHA-256: 9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2

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