Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d71bb31a440e34…

MALICIOUS

PDF

82.6 KB Created: 2021-09-01 21:49:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 1fc79c15d94a7671c56431cbea17cb1b SHA-1: f6bd71bf3ad1e423f1a72663e0bebc0878bbccfd SHA-256: 81d71bb31a440e34c7fc094776b0481d6caf5414e87c4af3cf6c5fc91bb78b03
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is identified as a malicious PDF by ClamAV and ML classifiers, indicating it's designed to exploit vulnerabilities or trick users. The presence of embedded JavaScript and numerous links, many pointing to potentially compromised or disposable hosting, suggests an attempt to redirect users to malicious sites or download further payloads. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports the idea that the document is a lure to drive traffic to external resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 7

  • 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.
  • 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 http://dalaichau.com/files/mukomuvaze.pdf In PDF document text
    • http://mygotour.com/FileData/ckfinder/files/20210529_C099633754D830A3.pdfIn PDF document text
    • http://runo34.ru/attachments/file/jewomob.pdfIn PDF document text
    • http://businessplan-capalpha.eu/mbp/upload/images/images/upload/ckfinder/89738948140.pdfIn PDF document text
    • http://zwickerfoto.hu/_user/file/zupunabe.pdfIn PDF document text
    • https://hgqq.hk/tony/churchofgod/ckfinder/userfiles/files/levubovapo.pdfIn PDF document text
    • http://compie.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b80454f01b4---wuseradoma.pdfIn PDF document text
    • http://sskj.pl/userfiles/file/jefakatopaminuwom.pdfIn PDF document text
    • https://batikatravels.com/userfiles/file/25604028186.pdfIn PDF document text
    • https://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160acdb3fa7946---83980429394.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/97bca22500dae8150c6fa2a99faa0eb0/gosibeturije.pdfIn PDF document text
    • http://falconfam.com/ckfinder/userfiles/files/28132213187.pdfIn PDF document text
    • http://uniquehotelsolutions.com/files/others/60865207748.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/revavewas.pdfIn PDF document text
    • http://studiopignotti.it/userfiles/files/tufubozatuvetavu.pdfIn PDF document text
    • http://allegroescrow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f2b17f15d3---54124061536.pdfIn PDF document text
    • https://www.litesourcenc.com/wp-content/plugins/super-forms/uploads/php/files/84ba388631fc80d14e18c54c06305354/kuwigapokubejutif.pdfIn PDF document text
    • http://kossuthdigisuli.hu/userfiles/file/faduzigobipe.pdfIn PDF document text
    • http://westernmaki.com/uploads/files/62641643704.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609b833839263---75493928315.pdfIn PDF document text
    • http://hourinkan.net/js/upload/files/fufuxoxodok.pdfIn PDF document text
    • http://portableandcool.com/files/files/gokurenedaneguwa.pdfIn PDF document text
    • http://ufnk.fr/app/webroot/files/file/84760383896.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=nippon+india+mutual+fund+redemption+form+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_off0000dfc3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFC3 17012 bytes
SHA-256: e7cc819e59d7ff26dfbdc07a8e77c4753fe8d1182f5f2101330da1a2a1cd418d
font_01_sfnt_off00010baf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BAF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000123c6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123C6 10568 bytes
SHA-256: 15516d77abc5b77bb63f9621c641fc92a9204c4e6663decc9ef8e22c8ff0aede

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