Malicious PDF — malware analysis report

Static analysis result for SHA-256 851f885097a4d6c8…

MALICIOUS

PDF

81.3 KB Created: 2021-03-19 12:05:04 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: aabbc9f6a06e63adfb9c0c0ec4fd4d2c SHA-1: fe1e8ec728038764e30bec14ece087a0757e981f SHA-256: 851f885097a4d6c87edcd96fb3d8a2bb708547d6a0c4430866aa399301fa80c4
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many hosted on disposable domains, suggesting a link farm or SEO poisoning tactic. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware delivery. The document body, though heavily obfuscated, contains metadata related to 'wkhtmltopdf' and a generator query, which is likely a lure to disguise the malicious nature of the links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://bologen.ru/strik?utm_term=what+kind+of+oil+does+a+powermate+generator+take PDF link annotation
    • http://zagodutaf.getenjoyment.net/catalogo_de_cuentas_de_una_empresa_industrial.pdfIn PDF document text
    • https://cdn.sqhk.co/folamudoj/Pjhgghc/cardiologia_dr_guadalajara.pdfIn PDF document text
    • https://cdn.sqhk.co/rezejigobip/jdichj8/pilot_logbook.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4406455/normal_604ec200594db.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496616/normal_5fd7901456ce8.pdfIn PDF document text
    • https://cdn.sqhk.co/lekuruzomef/icgfM8E/94554188366.pdfIn PDF document text
    • http://letgtma.bid/english_speaking_books_in_marathi_freeqv4c2.pdfIn PDF document text
    • http://gakagebir.mypressonline.com/62826767448.pdfIn PDF document text
    • http://nesobaka7.xyz/ley_de_ohm_ejercicios_resueltos_circuitos_en_paraleloib96i.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4476567/normal_60493d4beca01.pdfIn PDF document text
    • https://cdn.sqhk.co/towinomer/eiaiaCM/letterhead_software_free.pdfIn PDF document text
    • https://cdn.sqhk.co/zetikitor/gnjanMT/zombie_gunship_mod_apk_1._14_4.pdfIn PDF document text
    • http://sallehub.xyz/62090940248g458i.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393503/normal_5fd0eae236ecf.pdfIn PDF document text
    • https://cdn.sqhk.co/rapurakoke/jhwWhdz/65094973420.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4455403/normal_602de4234b39a.pdfIn PDF document text
    • https://cdn.sqhk.co/vajirasavuz/7ic1ige/97373141688.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://6f2fb29c-15f2-4b08-b525-3eb91a7f0a41.filesusr.com/ugd/c3548c_838559f7ca274605932c25b81940dfd1.pdf?index=trueIn PDF document text
    • https://3d6da986-5be3-4955-9d5c-e891e6c56a45.filesusr.com/ugd/3c671a_9efa31d3d204459884f8a6b02312bab0.pdf?index=trueIn PDF document text
    • http://tuwutexo.onlinewebshop.net/gopamamakadibuvi.pdfIn PDF document text
    • https://1160a196-6e18-49bd-931c-438029629b47.filesusr.com/ugd/40338c_bf390878c9e9483e924fa0c5cc1ab26e.pdf?index=trueIn PDF document text
    • https://c064424b-11a8-4e39-a524-24a74bcd733d.filesusr.com/ugd/54e393_2e5490ad597549d79a65481677465968.pdf?index=trueIn PDF document text
    • http://mawokale.myartsonline.com/how_to_replant_prayer_plant.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_off0000ed0e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED0E 5412 bytes
SHA-256: 2e0fed1985245fcefed33652b6a4be6aacbf057c2c46a1e4df840d506195db8f
font_01_sfnt_off0000ff5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF5E 12464 bytes
SHA-256: 1f603fc68998d1af73e7ba702eea8305c07106b604a18daba865800cde3730f6
font_02_sfnt_off00012912.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12912 4324 bytes
SHA-256: d1f4a20f0e35a0564be54678b929bb8c711862c507f070c2b9a6abea8daf4378