Malicious PDF — malware analysis report

Static analysis result for SHA-256 21e8fb0c7ba49dec…

MALICIOUS

PDF

86.6 KB Created: 2021-04-03 16:25:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-10
MD5: 979213902bb3291c76892bdd33e36915 SHA-1: 600f261f9a76993b9f27a18fcef113dc03844469 SHA-256: 21e8fb0c7ba49dec309bf6487fa4c2c47db7dbfae179a94a73ac1b74b3bae03a
126 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, indicating a link farm or SEO manipulation tactic. The ML classifier strongly flagged this PDF as malicious. While no scripts were directly extracted, the PDF structure and embedded URLs suggest an attempt to redirect users to potentially harmful 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.
  • 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://kuzutuzo.ru/strik?utm_term=where+did+serenity+prayer+originate PDF link annotation
    • http://worelimupuvefam.mywebcommunity.org/what_is_health_psychology_course.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4465125/normal_6041b712b5188.pdfIn PDF document text
    • https://linepofikoleku.weebly.com/uploads/1/3/4/4/134492010/kuwozimefekux_fagoxabizaneva_bomojotixero_pitozeme.pdfIn PDF document text
    • https://felonuwonab.weebly.com/uploads/1/3/0/8/130814100/rubalazafow.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4379601/normal_5fcd1048ebc1d.pdfIn PDF document text
    • https://sevebara.weebly.com/uploads/1/3/4/5/134501605/5437240.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4467027/normal_602fbfcfacd19.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4489593/normal_60051d53c1aff.pdfIn PDF document text
    • https://kopomitesukov.weebly.com/uploads/1/3/1/4/131453216/2560880.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4450345/normal_601245bf3f224.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4403410/normal_60126ea7dfec3.pdfIn PDF document text
    • https://sekuruzinof.weebly.com/uploads/1/3/4/8/134897543/f34340f8370.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4483839/normal_6056aa164a872.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4391620/normal_604b47c937e22.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://nejimafalun.onlinewebshop.net/how_to_write_biology_lab_report_example.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/52f616d5-a1e5-4ff1-8926-ac44ace37d1d/paula_deen_air_fryer_cookbook_amazon.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/eed5c2a5-3db0-4946-a820-da3726eadc69/how_do_you_reset_the_ice_maker_on_a_frigidaire_gallery.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/15a3cb2c-fce4-4755-b155-afe88df60ed6/bose_companion_2_series_iii_multimedia_speaker_system_pc.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_off00010575.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10575 4308 bytes
SHA-256: a34d96a3560713fb9881edd863570a1c84c9c93f8af6aad5972d6ef105989f4b
font_01_sfnt_off0001148b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1148B 5304 bytes
SHA-256: f1a11c38709b67e1f79a47a092991d3d9528b160a4251ba92ead4c583cbf570d
font_02_sfnt_off000126a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126A7 11676 bytes
SHA-256: 200e1a7fa609ba349a2782def95d5030bec88ee57ead718d9be58d78e06fce2d

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