Malicious PDF — malware analysis report

Static analysis result for SHA-256 8fbe36f678a81f30…

MALICIOUS

PDF

81.8 KB Created: 2021-09-08 21:50:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 35a8606cfcb9e5920669d4122798d9f6 SHA-1: 6f6ed2de3a627889fd41ddc16753176d1fca8840 SHA-256: 8fbe36f678a81f3075d7190ddaff3bab890bd9011c90e606f16e7873cb516b70
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristic analysis revealed it functions as a link farm, with numerous URLs pointing to other PDF files hosted on potentially compromised or disposable domains. This suggests a multi-stage attack, likely involving spearphishing, where the initial PDF serves to redirect users to further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://salt17.com/userfiles/files/mugogo.pdf In PDF document text
    • http://pck.malopolska.pl/wp-content/plugins/super-forms/uploads/php/files/ef0d9d7c4cf4d89239d97b7e3124be37/45343915114.pdfIn PDF document text
    • http://mutitar.com/user_img/files/76029012640.pdfIn PDF document text
    • http://theponghop.com/upload/files/23363351828.pdfIn PDF document text
    • http://rockefellersgold.hu/editor_up/32481524716.pdfIn PDF document text
    • http://tele-klass.ru/i/upload/files/5031544698.pdfIn PDF document text
    • http://xn----1-6cdapb2bdyqawnpcindqfc.xn--p1ai/media/file/10395977346.pdfIn PDF document text
    • http://aeskulap24h.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613690de8ab79---86303075621.pdfIn PDF document text
    • http://lerucherdesanges.fr/userfiles/file/jeganadubifugew.pdfIn PDF document text
    • http://eternoohydro.com/d/files/pifateludaxerapimidi.pdfIn PDF document text
    • https://auto826.vnpec.xyz/uploads/files/35339732822.pdfIn PDF document text
    • https://xn--49st2et51duvk.com/upload/files/28057883037.pdfIn PDF document text
    • http://greenmodels.ru/uploads/files/98047635794.pdfIn PDF document text
    • http://www.ashtralmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613062d31f6f8---30888388277.pdfIn PDF document text
    • http://kxqcgs.net/filespath/files/20210908161804.pdfIn PDF document text
    • http://svs-pm.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613252cce868d---20509183115.pdfIn PDF document text
    • https://phnews.ro/files/file/gadixiloviboruxejamodu.pdfIn PDF document text
    • https://turbooto.vn/upload/files/43091663789.pdfIn PDF document text
    • http://studiorapizza.it/userfiles/files/9247214974.pdfIn PDF document text
    • http://vedepcuaem.com/luutru/files/rekodevekupuriv.pdfIn PDF document text
    • http://sor1310.com/userfiles/file/nifalepedamozifak.pdfIn PDF document text
    • http://niengrangchuyensau.com/upload/contentFile/file/957464394.pdfIn PDF document text
    • https://global-brand.net/userfiles/files/53294841156.pdfIn PDF document text
    • http://solarwindependence.com/ckfinder/userfiles/files/pikerexugodakiwevevi.pdfIn PDF document text
    • http://silarperu.com/UserFiles/file/6041541898.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=ben+10+alien+force+game+androidPDF 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_off0000db91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB91 10780 bytes
SHA-256: 641f40554cdef5bf0c19475e78098710ac8e0b46a4e7da8e8604130628ca60a6
font_01_sfnt_off0000f429.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF429 17440 bytes
SHA-256: 37ef2ee121eb8a7297eef0c2d66f991b5639ba45dd7aaf1c8d93843c2c61eb0d
font_02_sfnt_off00012151.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12151 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1