Malicious PDF — malware analysis report

Static analysis result for SHA-256 850d57f4d7a854cd…

MALICIOUS

PDF

78.7 KB Created: 2021-03-24 20:06:04 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 42c129df7de17bbe3ddf8376972f429e SHA-1: b3183dc618493af99850ac7e138ee71f3930ce4e SHA-256: 850d57f4d7a854cdcc00d77079dd1a04c95ed024533bd38b264c3d7d9c72146e
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 are dynamically generated, indicating a link farm or SEO abuse tactic. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution. While no scripts were explicitly extracted, the PDF structure and embedded URLs point towards an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://nipisod.ru/wix?keyword=chemistry+stoichiometry+study+guide+answers
    • http://bidizujimon.getenjoyment.net/cisco_networking_all-in-one_for_dummies.pdf
    • https://cdn.sqhk.co/kugefiruxat/cibifjb/arizona_shooting_restrictions.pdf
    • https://cdn.sqhk.co/dedogupazib/eSbYxZC/subway_train_surfers_plus.pdf
    • http://nituzovido.getenjoyment.net/nematodes_download.pdf
    • https://cdn.sqhk.co/xejudawadoni/4Z0GZir/filamonudizevodobom.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • http://kigokigaruv.myartsonline.com/5_point_hedonic_scale.pdf
    • http://juludiripo.myartsonline.com/25142461865.pdf
    • https://uploads.strikinglycdn.com/files/b502687e-4648-4b60-9165-db2fc5436fa6/international_phonetic_alphabet_chart_english.pdf
    • https://uploads.strikinglycdn.com/files/8369a2db-aa2a-42a2-8542-374b979a940d/dozafapaxavejebo.pdf
    • https://s3.amazonaws.com/nutanigonu/94253116330.pdf
    • https://uploads.strikinglycdn.com/files/40374d52-91b7-43b1-87b9-909e038074b4/72686053311.pdf
    • https://s3.amazonaws.com/xidazeze/96027383002.pdf
    • https://6f465708-eb37-4ee2-8658-ebeec6cd93ea.filesusr.com/ugd/4bb103_d1067d84ed9544e0a1dc1d60b39deb17.pdf?index=true
    • https://uploads.strikinglycdn.com/files/3c6ededa-c317-4b62-b9fb-68e12dacbdef/vewenumifagigojapuneb.pdf
    • https://s3.amazonaws.com/zolerazowubow/84391860800.pdf
    • https://d3826037-6016-486c-99e9-dc41bc666644.filesusr.com/ugd/b81754_40db4521bb164f8ea352fb93bf8b1032.pdf?index=true
    • https://0306adf0-382e-42f1-903d-71c3961c97f1.filesusr.com/ugd/7ff653_4d0fb21461c242e1a2b86259867e4fbb.pdf?index=true
    • https://5a995288-ce6f-4ae3-a3e6-14272d8003db.filesusr.com/ugd/7be1cd_b5c35e48b628445bacda163fe5407f50.pdf?index=true
    • https://uploads.strikinglycdn.com/files/cdc9d6b1-a7b1-4c0f-bada-1f68618de47f/cuanto_equivale_3_metros_en_mm.pdf
    • https://44f39d5c-a655-4437-91b6-62b11e148e71.filesusr.com/ugd/eb4c03_4c9c67f222c842b8b6069893ece20873.pdf?index=true
    • 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_off0000e68f.bin
f10dfb737ab5b075607df17168d8cbf293c817520e8c521bf4e5207560fb60dd		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE68F 5420 bytes
font_01_sfnt_off0000f8ea.bin
c1e55fee01930308abaf1d68f5fab5bbcfbacef129c47b82d7865cc7c2485021		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF8EA 11160 bytes
font_02_sfnt_off00011f02.bin
9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11F02 4324 bytes

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