Malicious PDF — malware analysis report

Static analysis result for SHA-256 27931f1a8e0c81bd…

MALICIOUS

PDF

93.3 KB Created: 2021-04-06 00:10:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 619a5bd608280248220f358d0917e490 SHA-1: 3065b10e84f8f364b014a8a8a8331de9f97646fe SHA-256: 27931f1a8e0c81bd407f19017e5d8bd8002616a3ae7c7f86e6df1b920d9e09f0
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to disposable domains, and is flagged by ML classifiers and ClamAV as malicious. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a tactic to obscure malicious links within a large number of seemingly legitimate ones. The primary malicious URL identified is 'https://golowaki.ru/strik?utm_term=la+casa+de+bernarda+alba+acto+1+pdf', which likely serves as a phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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://golowaki.ru/strik?utm_term=la+casa+de+bernarda+alba+acto+1+pdf PDF link annotation
    • http://urro-hu.com/transformational_leadership_scholarly_articlesxx1g8.pdfIn PDF document text
    • http://ostanni.fun/why_does_my_4_wheeler_battery_keep_dying2146i.pdfIn PDF document text
    • http://nagozubotejelaj.iblogger.org/fakajagoniwobafuragifev.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4447280/normal_5ff3e635b0a2f.pdfIn PDF document text
    • http://mukinokelek.mygamesonline.org/cambridge_pet_for_schools_1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4459926/normal_60305aa44fa40.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4444864/normal_604fbb350ced2.pdfIn PDF document text
    • http://tells.fun/loxikos43hxe.pdfIn PDF document text
    • http://bazunujovi.scienceontheweb.net/microeconomics_book_class_11_sandeep_garg.pdfIn PDF document text
    • http://wirelessinfo.ru/882472355335qgv9.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/lorifumofelu/cookie_jam_blast_pc.pdfIn PDF document text
    • http://jokubizipapazor.epizy.com/online_convert_any_doc_to.pdfIn PDF document text
    • http://mijofifekokug.rf.gd/why_subscribe_to_twitch_channel.pdfIn PDF document text
    • https://3cd6846c-369c-4875-9c63-132df726a2dd.filesusr.com/ugd/7ab50f_ce2e1db20e9644ec97868dbaefe53c55.pdf?index=trueIn PDF document text
    • https://14579757-8399-40ae-9aa0-1c510f02119b.filesusr.com/ugd/5613ee_6f1651ab09d34d88a0524a1e28c26697.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/nilafafakem/how_to_install_electric_pet_fence.pdfIn PDF document text
    • https://9cf93ecd-64ee-4ad6-afcc-f350577a7522.filesusr.com/ugd/c4dbd3_b116e77b73974995952d1eb9003b32d9.pdf?index=trueIn PDF document text
    • https://4b0cdf75-2e42-4830-99f1-bbdbaec3f661.filesusr.com/ugd/891219_42ed0c4c214640b1a9079d017b5b1cf2.pdf?index=trueIn 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012c68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C68 5284 bytes
SHA-256: 9e72cf1dd8be152ea88f393cbe78af329981b9c4e78770f123c082d102e58c46
font_01_sfnt_off00013e6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13E6A 12536 bytes
SHA-256: acb42f47c091802088211c6ee5abd9c1274c01fdf31eab753b8fa3750b6d0c63

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