Malicious PDF — malware analysis report

Static analysis result for SHA-256 c3f53f76875c3dda…

MALICIOUS

PDF

104.3 KB Created: 2021-03-26 09:19:07 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-02
MD5: 0af64542a9ce4b54cc5e376acd5ebab6 SHA-1: edb2eb423c63c3a84745f61dd99b8d9c65909e6d SHA-256: c3f53f76875c3dda1dba87cf0dc1e3ba190c26daeb28fca7f4d1b307a6d19ddc
126 Risk Score

Malware Insights

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

The PDF file contains numerous external links, with a significant portion pointing to disposable hosting and employing UTM parameters, indicative of link farming or SEO manipulation. The ML classifier strongly flagged this PDF as malicious, and the presence of embedded URLs further supports malicious intent. The primary URL, 'https://xajibur.ru/strik?utm_term=what+air+fuel+ratio+at+idle', is likely the malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://xajibur.ru/strik?utm_term=what+air+fuel+ratio+at+idle PDF link annotation
    • https://cdn.sqhk.co/lezebulodiw/hb8jgKN/murder_mystery_2_codes_2020_sep.pdfIn PDF document text
    • https://cdn.sqhk.co/pijavagoke/gjjesZ0/bizeji.pdfIn PDF document text
    • https://cdn.sqhk.co/rojarimeg/27bggm9/rasemigelegolinewe.pdfIn PDF document text
    • https://cdn.sqhk.co/wepiwojeta/cjjhhXk/woguluvagatijivabaji.pdfIn PDF document text
    • https://cdn.sqhk.co/resilano/agc2aXj/megitujorebotizixa.pdfIn PDF document text
    • https://cdn.sqhk.co/vonixilavot/cjfGyjj/bluffton_south_carolina_flood_map.pdfIn PDF document text
    • https://cdn.sqhk.co/rujiwujik/jejgT8g/masuretedefuxefibalefigo.pdfIn PDF document text
    • https://cdn.sqhk.co/pigajifaw/hbBgihc/events_near_here.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/d6244bea-2a4a-40e4-807e-a5fdf3a7363f/27892090500.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/249549fd-c08c-49cd-9928-2b762d57b4be/24368452862.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f626e2b9-c07a-4faa-b449-d5b2bfb8f373/fimibirobirumevuva.pdfIn PDF document text
    • http://bipaxoxibiva.rf.gd/tovazumiledes.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1a183bd9-c7df-41c4-9950-cd01cfd70190/keratitararofakox.pdfIn PDF document text
    • https://d872ce2a-2baf-4032-ab86-ab75b2f66d52.filesusr.com/ugd/338562_0fc2104085694197b54b15bd8df85d6f.pdf?index=trueIn PDF document text
    • https://ef9935f7-a918-44a1-999f-f1d50a45e4a7.filesusr.com/ugd/b463f2_86facd1b12e14cdaab76101a1a001d6e.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/96812844-3b71-4eba-a902-416ff74465e0/pebble_smartwatch_battery_replacement.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ef5732af-151f-4f87-aa62-ea88d4e383cc/how_to_open_lenovo_thinkcentre_m820z.pdfIn PDF document text
    • https://36fde204-cda4-4268-899b-58717f9005d0.filesusr.com/ugd/b13063_74ec2eb268634f88962a82d947f7ea4a.pdf?index=trueIn PDF document text
    • http://rujugojokukasav.rf.gd/mary_balogh_libros.pdfIn PDF document text
    • https://ebed6276-6372-4ddf-adad-9a0fa504b99f.filesusr.com/ugd/805d2a_2350c05af0f04299b81436f160718e6e.pdf?index=trueIn PDF document text
    • http://gogadotonirad.rf.gd/mipezop.pdfIn PDF document text
    • http://xidozuk.rf.gd/93079394529.pdfIn PDF document text
    • http://zufagubiles.epizy.com/cema_standard_for_belt_conveyor.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/47c4df02-8f4f-4008-aceb-7b121fe1fb71/pinijidosiranojexo.pdfIn PDF document text
    • https://ba739632-11db-41f7-a023-683a20e55d36.filesusr.com/ugd/99835b_9786c12e6b1a49d883616d47c4fcab1e.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_off00015da6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15DA6 4832 bytes
SHA-256: a29e5d890016dfe0f01d4abec27d430ec6cac4bff3de860eb318789666deb02f
font_01_sfnt_off00016e18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16E18 11140 bytes
SHA-256: 8874e9c9f1ce36df50edf88cc23e1d52cfdcf86888b4f7a9ff695983b8fa7608