Malicious PDF — malware analysis report

Static analysis result for SHA-256 6a672a798c792bf0…

MALICIOUS

PDF

74.4 KB Created: 2021-03-27 16:13:48 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: ea49abd263656719195d6d7d6506ef6e SHA-1: 52b01451faa3f30eaa9debf2eda18ab2181d2f1c SHA-256: 6a672a798c792bf02b77e4f2392f3815ec38bcbe2bd98a9d5ce2fe5afbe9b646
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a large number of external links, many hosted on disposable domains, indicating a link farm or SEO manipulation tactic. The primary URL, 'https://nipisod.ru/award?keyword=budget+constraint+questions+and+answers+pdf', suggests a lure to a site potentially involved in phishing or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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
  • 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://nipisod.ru/award?keyword=budget+constraint+questions+and+answers+pdf
    • https://cdn.sqhk.co/fabunavaxa/jbiihgo/pujudevejupakebazolog.pdf
    • https://cdn.sqhk.co/wirowanorax/hfhcbsC/baby_bjorn_potty_trainer.pdf
    • https://wezusutuxalik.weebly.com/uploads/1/3/1/6/131637092/zatemexifap-pakijor.pdf
    • https://xadigepuve.weebly.com/uploads/1/3/1/4/131454317/3f5b6.pdf
    • https://metuliwilive.weebly.com/uploads/1/3/4/3/134386481/vuwolalinewam-dovekono-nopolez.pdf
    • http://zagodutaf.getenjoyment.net/word_meaning_with_synonyms_and_antonyms.pdf
    • https://tolutewegudef.weebly.com/uploads/1/3/4/0/134097468/2508521.pdf
    • https://cdn.sqhk.co/vuxesojogugu/biamIid/bts_songs_2020_app.pdf
    • https://bokesavuxi.weebly.com/uploads/1/3/0/9/130968985/025921212df309.pdf
    • http://zukesijinizik.mywebcommunity.org/blood_collection_tubes.pdf
    • https://cdn-cms.f-static.net/uploads/4409799/normal_6029d7443ab00.pdf
    • https://static.s123-cdn-static.com/uploads/4369161/normal_5fe4005f8dddb.pdf
    • https://mikezibe.weebly.com/uploads/1/3/1/4/131453119/9168068.pdf
    • https://fojakodi.weebly.com/uploads/1/3/1/3/131379163/5722510.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://uploads.strikinglycdn.com/files/6d79cc75-9e5a-4ef2-90c7-9a9ee264029b/learn_korean_alphabet_pronunciation.pdf
    • https://uploads.strikinglycdn.com/files/3de82eeb-1c56-400a-8d00-bfde5076d3cb/ciclo_de_contabilidad_de_costos_por_ordenes_especificas.pdf
    • 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_off0000d86e.bin
2788665d38582e730fc268cc7f371773bddc828f1b49995705a2c5d46cc53618		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD86E 5440 bytes
font_01_sfnt_off0000eb08.bin
aeb745d67de57f9aead6ac5e2241a8897bdcc46a3ac3e365196fb74591aed039		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEB08 10340 bytes
font_02_sfnt_off00010e5f.bin
d1f4a20f0e35a0564be54678b929bb8c711862c507f070c2b9a6abea8daf4378		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10E5F 4324 bytes

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