Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f37bd527b2a80e…

MALICIOUS

PDF

96.1 KB Created: 2021-09-08 00:03:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 05663639dc2c8bb81dd8bbeacfb58063 SHA-1: 40f75cd250f7102410ad3b018a6b0a520d9341c2 SHA-256: 81f37bd527b2a80eac227330923812928de8cbcd4e391a85aadf2093caa5ae99
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, a common technique for malicious PDFs to execute code or redirect users. Heuristics indicate it's part of a link farm hosted on compromised or disposable domains, suggesting an attempt to distribute phishing content or malware. The ClamAV detection and ML classifier strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://dvg.asia/ckfinder/uploadfiles/files/lajesutixowi.pdf In PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a23cda8577d---78301230423.pdfIn PDF document text
    • http://seamacros.com/upload/file/28721778656.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c7718050176---zapez.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/161108bf7065dc---katupaku.pdfIn PDF document text
    • http://business-plan-capalpha.eu/mbp/upload/images/images/upload/ckfinder/108166969.pdfIn PDF document text
    • http://grani-tonkogo-mira.ru/wp-content/plugins/super-forms/uploads/php/files/98e5218e1613cb51b02499c73b343500/64367184463.pdfIn PDF document text
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607ae90b94797---nobumegupatulo.pdfIn PDF document text
    • http://dfwsedan.com/nbloom/fckuploads/file/tezugejikud.pdfIn PDF document text
    • http://www.magicapro.it/wp-content/plugins/formcraft/file-upload/server/content/files/160acfba9711fb---70365385339.pdfIn PDF document text
    • https://gikguamerica.com/userfiles/file/58395344388.pdfIn PDF document text
    • http://leadingedgecorporate.com/user_images/file/kogaw.pdfIn PDF document text
    • https://peoplesmodelinternational.com/ckfinder/userfiles/files/fevuwem.pdfIn PDF document text
    • https://marblobathware.ph/app/webroot/img/files/65026026410.pdfIn PDF document text
    • http://www.justgiveahand.org/wp-content/plugins/formcraft/file-upload/server/content/files/160ad0844e1908---97694105965.pdfIn PDF document text
    • http://ccadl.com/files/20210804110931.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16084c03e37a08---6666869240.pdfIn PDF document text
    • https://www.hemingway.bg/app/templates/js/ckfinder/userfiles/files/rigeguxatuvusudu.pdfIn PDF document text
    • http://word.mn/uploads/assets/33765251413.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/160a2a9a938e61---lupalalijenanefonepijewu.pdfIn PDF document text
    • https://izometal.net/mm/file/84514197512.pdfIn PDF document text
    • http://csc0535.com/userfiles/file/20210629062521_6n1ayp.pdfIn PDF document text
    • http://www.lbf-cosmetics.com/website/wp-content/plugins/formcraft/file-upload/server/content/files/16071387a51328---66563494683.pdfIn PDF document text
    • https://kuechentreff-schmid.de/wp-content/plugins/super-forms/uploads/php/files/mnudi3f7jf0hc6aiu573eudc7t/34561179698.pdfIn PDF document text
    • http://capmar.eu/userfiles/file/35530941014.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=free+bedtime+stories+for+babies+in+the+womb+pdfPDF 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_off00011383.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11383 17984 bytes
SHA-256: ac0ee3fc4dfbdac6692fe16a5c38a7771042bea6fa9f3100a5bb4c236307af7c
font_01_sfnt_off0001412c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1412C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015943.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15943 10920 bytes
SHA-256: 67c327ec3e7c2be99644c193f885ed59cc230f98bdb00ca11265c9e506c0cbe7