Malicious PDF — malware analysis report

Static analysis result for SHA-256 3a8cecb48c8bdbb2…

MALICIOUS

PDF

85.8 KB Created: 2021-09-06 23:16:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: e828d2f96154caaa1ac9a1358bc8e359 SHA-1: 61de090117669aa0d3ee249ee1edd63c62584dc2 SHA-256: 3a8cecb48c8bdbb2deee57594ecab98865d894dc8b915c0853e3cb8a8cb758e8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of embedded URLs, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm designed to redirect users to malicious destinations. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates these links are likely used for SEO poisoning to attract victims. No scripts were extracted, but the primary attack pattern involves redirecting users via these URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://synerhu.ru/uplcv?utm_term=sistemas+lineares+exercicios+pdf PDF link annotation
    • http://kcobafl.org/ckfinder/userfiles/files/bugasoxikuxewodalusi.pdfIn PDF document text
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab8566e65e5---kumulupagofexoduko.pdfIn PDF document text
    • https://centar-znr-zop.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160a6c7e2038f0---rafobunujafupaxedaveba.pdfIn PDF document text
    • https://conexkarvan.com/cache/fck_files/file/tewolabetovawuj.pdfIn PDF document text
    • https://srmresidences.com/images/bulk_images/files/30747131563.pdfIn PDF document text
    • http://wingmanplanningdemo.com/userfiles/files/mezepuvinefipumapemegex.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16086cba032f8f---26576833351.pdfIn PDF document text
    • http://graphicon.hu/wp-content/plugins/formcraft/file-upload/server/content/files/1607af43bbbdb9---mapujamosefi.pdfIn PDF document text
    • https://istanajp2.com/contents//files/20365162703.pdfIn PDF document text
    • http://elonsummerstorage.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098393249a93---10207822612.pdfIn PDF document text
    • https://precisionautoandac.com/wp-content/plugins/super-forms/uploads/php/files/d1f32c48bf31617475ea167e92da2e34/16083629691.pdfIn PDF document text
    • https://onlinendttraining.com/files/belofebijenonesiw.pdfIn PDF document text
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/160837bbd016ea---dezedaxalujulijalite.pdfIn PDF document text
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/843dcmlj0aj636lvavfe8g3nca/vulususuven.pdfIn PDF document text
    • http://naasschoolofmotoring.com/fckeditor/userfiles/file/lavexijidewewo.pdfIn PDF document text
    • https://www.cifphosteleriayturismo.es/ckfinder/userfiles/files/fujikaxigiwipenisuwito.pdfIn PDF document text
    • http://stalmost.pl/userfiles/file/dulemazodifumilorum.pdfIn PDF document text
    • https://www.truesdalepainting.com/wp-content/plugins/formcraft/file-upload/server/content/files/16105161e74194---nevopugavav.pdfIn PDF document text
    • http://marcth.pl/media/fck/file/17787931060.pdfIn PDF document text
    • http://ardechetendancebrut.fr/userfiles/ardechetendancebrut.fr/file/44740172830.pdfIn PDF document text
    • https://venefoil.com/ckfinder/userfiles/files/72571030579.pdfIn PDF document text
    • https://piataafacerilor.ro/app/webroot/files/userfiles/files/xoxawamitoxoz.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_off0000e35b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE35B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fb6d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB6D 20188 bytes
SHA-256: b69449ebf24c1eec4ca1b97d63c860756ae5fcd152c9f4b3dd6bfbf9239773f3
font_02_sfnt_off00013071.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13071 10960 bytes
SHA-256: 8da1484758fe3a2ba1edbd099b31fe1b229469a9db8ce6668b4bba557180b6ce

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