Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef1effba3dc85de4…

MALICIOUS

PDF

90.3 KB Created: 2021-06-27 14:25:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 16e51ff9b672c8518039d4f1f1ce9203 SHA-1: 837d608753c4ef863c861f3824c03b7cccace417 SHA-256: ef1effba3dc85de497885196f16135eef99292a868333054c98a574b97fcd5b5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised WordPress sites, suggesting a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly indicate malicious intent. While no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a malicious link farm designed to lure users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9932

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://krisoc.ru/uplcv?utm_term=x+lite+download+free+for+windows PDF link annotation
    • http://dianacb.cz/userfiles/file/3225201104.pdfIn PDF document text
    • https://szabobuszrendeles.hu/files/files/putaboburol.pdfIn PDF document text
    • http://www.infranetltd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082e62718335---36274069177.pdfIn PDF document text
    • https://gangnampools.com/contents//files/46731443425.pdfIn PDF document text
    • https://chocoinmobiliario.com/wp-content/plugins/super-forms/uploads/php/files/b50021be4123fe06efe0ba824a058414/jigeri.pdfIn PDF document text
    • http://dolphinkorea.com/files/files/wemidix.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/15b909b1e0d967b380bf4598796384e8/29159613158.pdfIn PDF document text
    • https://outsourcedbackoffice.co.uk/wp-content/plugins/super-forms/uploads/php/files/825c47f99dddb441939cb30bfe00d681/98991100926.pdfIn PDF document text
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/77b382597a4562e66d1a025be9b18fe4/nuwogexekolizew.pdfIn PDF document text
    • https://www.reliancecareuk.com/wp-content/plugins/super-forms/uploads/php/files/c5eab38400df7621f6065845ae966b46/xetinadigelutemixeka.pdfIn PDF document text
    • http://vidol.nl/userfiles/file/11833049490.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/39065bdcf87ec47811c3006279d5ccc7/leduvitudafalewufutilo.pdfIn PDF document text
    • https://www.lavishlook.se/wp-content/plugins/super-forms/uploads/php/files/3eabda9cdae7ab05a62e2e68fb9df064/rawupevo.pdfIn PDF document text
    • http://zawayakw.com/wp-content/plugins/formcraft/file-upload/server/content/files/160afbe5e2a1d3---rigapi.pdfIn PDF document text
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/tli1e2umd7g36ft1f7obdgamhn/85321368558.pdfIn PDF document text
    • http://misspacificus.com/clients/873634/File/78291086999.pdfIn PDF document text
    • http://aarogyamedico.com/userfiles/file/webexaxedigugi.pdfIn PDF document text
    • https://bestmiamiturf.com/wp-content/plugins/super-forms/uploads/php/files/bef08abb2e7b2a2163c893e21522d671/vogepevoseduduveteduz.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1608c1177d5ef6---28276366691.pdfIn PDF document text
    • https://californiaoptionsrealestate.com/wp-content/plugins/super-forms/uploads/php/files/faa5e935e1a54a79b954b74354f20201/21472766546.pdfIn PDF document text
    • http://askort.pl/Upload/file/regemu.pdfIn PDF document text
    • http://xperion.hu/wp-content/plugins/super-forms/uploads/php/files/844ae1baf914eb7243540c97ecb6b8dc/81539065902.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e883.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE883 17260 bytes
SHA-256: 7198f4f5baeeaf1c8d284aa040aaef9bd26f7bb0b53bb2f4bae40a4f52caf172
font_01_sfnt_off000115b8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115B8 10440 bytes
SHA-256: 2d3fefdb1ff53cfcad59716689af7a7a05516f8f84bf015725e0ffd7da1d00ae
font_02_sfnt_off00012d91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D91 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off000145a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x145A2 16252 bytes
SHA-256: 15510956be7ead9f824e209a6104b8be563ded270a313a9f6e525002084f8b58

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