Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb7966029a6e411b…

MALICIOUS

PDF

75.5 KB Created: 2021-02-10 16:35:42 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 39f586cfa5ce1dfc127313d3e050eaa2 SHA-1: b507b4e01a91c64d34b9e8e9f37047c15f7a493e SHA-256: cb7966029a6e411ba9604b7dd2181efcdf2517be225b9da9c32ebff296e9248d
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, many hosted on disposable domains, suggesting a link farm or redirection scheme. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The document body, though heavily corrupted, contains text related to a 'welcome letter to parents', which is likely a lure to disguise the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://jacksth.ru/123?utm_term=welcome+letter+to+parents+from+kindergarten+teacher PDF link annotation
    • https://cdn.sqhk.co/wifopuzuxiba/gtF22hi/pc_simulator_no_os_found.pdfIn PDF document text
    • http://numberoone.xyz/kartrider_rush_rank_tierzd0pt.pdfIn PDF document text
    • https://cdn.sqhk.co/fubafonu/fjejjxD/small_world_zurich_central.pdfIn PDF document text
    • https://cdn.sqhk.co/vomikigiw/5Sicov7/aviemore_loop_kingsley.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4475725/normal_5ffbf6470ce1c.pdfIn PDF document text
    • https://fikuvigobe.weebly.com/uploads/1/3/4/5/134582673/pamuzi_xedopogenajitov.pdfIn PDF document text
    • http://goodsun.fun/word_stacks_level_139i83b3.pdfIn PDF document text
    • https://cdn.sqhk.co/gokovolasula/djjgiKP/sandwich_recipes_vegetarian.pdfIn PDF document text
    • http://cleanup-sale.site/yards_to_meters_conversion_tableddx99.pdfIn PDF document text
    • http://kind-insta.site/download_yasin_tahlilct5d5.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4454820/normal_6006012bba47f.pdfIn PDF document text
    • https://cdn.sqhk.co/xanapaje/ggJjaTg/68113529142.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
    • http://zuxujofuteme.rf.gd/86381616082.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_off0000dc25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC25 5436 bytes
SHA-256: ca6a4cbe94ecda384cfc0d448ee69c3ec17df11a666395a12a6db1b24d4c1346
font_01_sfnt_off0000ee74.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE74 10476 bytes
SHA-256: cd5fd17e8b81e05c238728d479c0ff4ea8b5ba2842ad7e51600c86b8b4385e59
font_02_sfnt_off0001125e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1125E 4324 bytes
SHA-256: 1158d95dac44631f497756703988ba3645251422e7ff0015d3fca430225e7c3e

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