Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f19157feb8c878a…

MALICIOUS

PDF

92.5 KB Created: 2021-09-03 10:34:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 8fd3ef8b70500a931a2f0877278ae69e SHA-1: 0a34192e03d394639be5cd5eeeac44da66ecf1a3 SHA-256: 4f19157feb8c878a65bb05977f0d4a0d1dbd0a01486e7654037dcd9b902d745f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file is identified as malicious by ML classifiers and ClamAV, indicating it's a phishing or trojan distribution attempt. It contains numerous links to compromised WordPress upload directories and disposable hosting, suggesting it's designed to redirect users to malicious content. The embedded URLs, such as 'https://coretry.ru/uplcv?utm_term=syllogism+problems+with+solutions+pdf', are likely part of a link farm designed to improve search engine ranking for deceptive search terms and lead victims to malware or phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://coretry.ru/uplcv?utm_term=syllogism+problems+with+solutions+pdf PDF link annotation
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609fdf49c8bf9.pdfIn PDF document text
    • http://elmiraclassiccountry.com/wp-content/plugins/super-forms/uploads/php/files/750cc8e9bfa1705311dd207b2da3d598/getifojuwunenisipe.pdfIn PDF document text
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/gf4pq45hjo0p1ql3d0upfa5qsb/46658566779.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb81ae715e---33861919478.pdfIn PDF document text
    • http://interno-kazan.ru/upload/files/28939659603.pdfIn PDF document text
    • http://mazurubezpieczenia.pl/zdjecia/fck/file/88953964126.pdfIn PDF document text
    • http://grimastone.ru/files/62986630881.pdfIn PDF document text
    • https://grafitpoint.ru/wp-content/plugins/super-forms/uploads/php/files/32baa1b8a44f73241ac026ef3e59e709/37375230795.pdfIn PDF document text
    • http://xn--80aejmo0alc.xn--p1ai/ckfinder/userfiles/files/nolatowonupozajujiri.pdfIn PDF document text
    • http://copy2d.com/ftp/image/file/sekov.pdfIn PDF document text
    • https://thejinglelab.com/wp-content/plugins/super-forms/uploads/php/files/1u1na424dcarbg76tctfqtol39/80902616556.pdfIn PDF document text
    • http://ehsclassof64.com/clients/b/bf/bfa5c4411462ceee4a19e543862d902c/File/vapuwexowebasu.pdfIn PDF document text
    • http://www.klpreschool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608eca27d98cd---80291615173.pdfIn PDF document text
    • http://www.tsahimmongol.com/uploads/images/files/65843791995.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070ce300b55b---31020119475.pdfIn PDF document text
    • http://grupomarsamo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083e952e991d---nogitemifek.pdfIn PDF document text
    • http://cochu.net/resimler/files/30199623538.pdfIn PDF document text
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/160861df824d91---wekotub.pdfIn PDF document text
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160af45d6881ad---50962912183.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160877c9217794---77880123643.pdfIn PDF document text
    • http://biolabsrl.org/userfiles/files/javojumokovafafuzaparef.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://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_off000103df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103DF 11296 bytes
SHA-256: 60559b6700fad2a893c1c96c0c846014476524dba262ad925841bccf2d251851
font_01_sfnt_off00011dca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DCA 17564 bytes
SHA-256: 57e68d8ea3825ad23981a561712ce080d4fff9f14aa10c8a1be376ce21bb7989
font_02_sfnt_off00014bdd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14BDD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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