Malicious PDF — malware analysis report

Static analysis result for SHA-256 4ae66329a6d4a358…

MALICIOUS

PDF

75.7 KB Created: 2021-09-19 20:34:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 0dcd9c746c3a3557c09a3f1cb61e78d8 SHA-1: 4a2e3302bd37fa921a6b37f063efb955288ed613 SHA-256: 4ae66329a6d4a358a4b50a0fb779e5674834552ead9d06c040219fcd8d8dec4b
106 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file exhibits characteristics of a link farm, with a high number of external URLs pointing to potentially malicious content. The ML classifier strongly indicates maliciousness. While no scripts were directly extracted, the presence of numerous PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics suggests an attempt to distribute malware or redirect users to phishing sites, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 5

  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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 http://stefanourso.com/public/userfiles/file/wobunajapepezaxiz.pdf In PDF document text
    • http://back2wood.de/userfiles/file/lofibaripominevofumuzex.pdfIn PDF document text
    • https://plagij.at/ckfinder/userfiles/files/87188775402.pdfIn PDF document text
    • https://digireg.es/upload/fowuwifizezij.pdfIn PDF document text
    • http://s-pack.kr/userfiles/file/20210915171514.pdfIn PDF document text
    • https://gea99.com/ckfinder/userfiles/files/mudumigamovixob.pdfIn PDF document text
    • http://www.tractortools.cz/ckfinder/userfiles/files/repinasatajisifupawovud.pdfIn PDF document text
    • http://lezeckastenakosice.sk/upload/files/xafimeze.pdfIn PDF document text
    • https://netwindowvn.com/uploads/userfiles/file/21814611623.pdfIn PDF document text
    • https://lenaoyunlar.net/calisma2/files/uploads/40643997061.pdfIn PDF document text
    • http://vekosgroup.ru/userfiles/file/mutitomevidajogoxijikulav.pdfIn PDF document text
    • https://renebeumer.nl/userfiles/file/9687052578.pdfIn PDF document text
    • http://www.brickchamber.com/ckfinder/userfiles/files/malodoxaxefevapep.pdfIn PDF document text
    • http://gcsiva.com/files/userfiles/file/45045143993.pdfIn PDF document text
    • http://xn--80aer5aza.xn--c1acndkmcarx.xn--p1ai/ckfinder/userfiles/files/73617915446.pdfIn PDF document text
    • http://alemotta.com/resources/original/file/94622375363.pdfIn PDF document text
    • https://tmtteks.com/files/81655720824.pdfIn PDF document text
    • http://stardentalcare.org/userfiles/file/tupetudekokegapebujogalaf.pdfIn PDF document text
    • https://smwebtechnology.com/arishayurveda.com/userfiles/file/bewot.pdfIn PDF document text
    • https://saleskerala.com/ckfinder/userfiles/files/52413949695.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/66191392638.pdfIn PDF document text
    • http://ozhelalikram.de/resimler/files/13784102629.pdfIn PDF document text
    • https://ltes2.tw-goods.com/UserFiles/files/puxenokapofaluneve.pdfIn PDF document text
    • http://mevlanaasm.com/resimler/files/67258578986.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=firmware+mxq+pro+4k+rk3228aPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c2a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC2A5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000dab7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAB7 17568 bytes
SHA-256: 4d5037995d7e8588e6256dd07902685d733d56455a5d475d6fe83ab53e149ca8
font_02_sfnt_off000107db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107DB 10980 bytes
SHA-256: dc4a17fb1227669fffbbcd1f15ea81e39237a4648cd6bc57f4423f0cc22aaa99

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