Malicious PDF — malware analysis report

Static analysis result for SHA-256 23fc231f09c45b71…

MALICIOUS

PDF

85.0 KB Created: 2021-08-21 11:29:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: f6d79c432e8c0787451df4e807c2bf77 SHA-1: c7a384f359bf35fdaa4f6fa87176e967d342315c SHA-256: 23fc231f09c45b71fbce294cd48d0f6b2590ed032ada0792f2419e7c7af7d95d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier indicating a high probability of malware. It contains numerous embedded URLs that point to compromised WordPress sites and function as link farms, likely intended to redirect users to phishing sites or download further malicious content. The document body is heavily obfuscated, suggesting an attempt to hide its true malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://cructi.ru/uplcv?utm_term=free+addition+and+subtraction+worksheets+with+regrouping PDF link annotation
    • https://extremetour74.ru/wp-content/plugins/super-forms/uploads/php/files/3a5b8da8e5c49e08397d5533e37c786d/93844390155.pdfIn PDF document text
    • http://ouhkpthaa.org/userfiles/61640961122.pdfIn PDF document text
    • http://apartamentosalbatros.com/wp-content/plugins/formcraft/file-upload/server/content/files/160804a2f4df0f---vojanutixowigatawumaj.pdfIn PDF document text
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160df7eda88d18---vipezodizaropugosu.pdfIn PDF document text
    • https://ecef-groupe.com/wp-content/plugins/super-forms/uploads/php/files/vir9ko6q3ki2c489gthq10lbr7/tavoxelomorerix.pdfIn PDF document text
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cbd1a52c76---zopukugugorifavileteb.pdfIn PDF document text
    • http://rhondachem.com/d/files/6544988270.pdfIn PDF document text
    • https://avvocatoboretti.it/file/xosuvexasubijotukuxegagum.pdfIn PDF document text
    • http://europavloeren.nl/siteimages/file/13873127297.pdfIn PDF document text
    • http://neuragen.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160fccd6318aad---nixevevidakikigukemokofej.pdfIn PDF document text
    • http://ixtvs.de/_upload_bilder/_filemanager/file/tutogusutevelozikosibo.pdfIn PDF document text
    • http://creptiles.dk/userfiles/file/zunidikuxib.pdfIn PDF document text
    • http://videoacceso.com/wp-content/plugins/formcraft/file-upload/server/content/files/160798ff6ad2b5---kolamuporopogiporavapej.pdfIn PDF document text
    • http://baanpowertrain.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078251aed6e7---55865711738.pdfIn PDF document text
    • http://tnshoppingbag.com/upfiles/file/92157891163.pdfIn PDF document text
    • https://cms.blauraum.com/wp-content/plugins/super-forms/uploads/php/files/6efc910925f1e2c35c8b3d2241b1319e/nasumekirune.pdfIn PDF document text
    • http://ecohouse-lab.com/userfiles/file/raxozafetalutixujajokosa.pdfIn PDF document text
    • http://americanewbie.com/userfiles/file/losemon.pdfIn PDF document text
    • https://krimgranit.ru/wp-content/plugins/super-forms/uploads/php/files/64209bb1bc1c7922973d71348f880e91/26929061450.pdfIn PDF document text
    • https://cashofferoregon.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6d1da64a45---pimamikukubitobojuvaber.pdfIn PDF document text
    • https://www.chinacimctrailer.com/wp-content/plugins/super-forms/uploads/php/files/72ae18b9cc06250a3093345c6e960eff/bexebemovizumu.pdfIn PDF document text
    • https://muguet.fr/sites/default/files/file/3221511584.pdfIn PDF document text
    • http://slp61.com/clients/e/e2/e296dcecfd7d10ffef0cc83fef253c72/File/susijona.pdfIn PDF document text
    • http://ezibra.pl/upload//file/venagozajawikuga.pdfIn PDF document text
    • https://www.corridar.com/wp-content/plugins/super-forms/uploads/php/files/jpnod3mcqgn0ka1hnls11itl3q/rejiseru.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_off0000e52d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE52D 17340 bytes
SHA-256: 2084540b134747a26363c13c4a14f0101c34d62474cad682c3bf3dfa5f5dc1f2
font_01_sfnt_off000112d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112D2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012ae9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12AE9 11144 bytes
SHA-256: 3c5c98ddd4b7627f4144ff6817271e7f49cd6bf20e2a2f29a475ebd9628cff9a

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