Malicious PDF — malware analysis report

Static analysis result for SHA-256 73cefbb8a548af7c…

MALICIOUS

PDF

81.8 KB Created: 2021-09-03 09:44:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-02
MD5: 67390db0b37797029c73e99a68e34915 SHA-1: 77d4c9d7fc40fe4546c783dd6f8745c832402e4f SHA-256: 73cefbb8a548af7ce93a9e3fa5aa668bb5d2d3cb2980a599c2dd009d000b9ee3
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9353

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://somogyplusz.hu/files/kilumelukumosowelitodiru.pdf In PDF document text
    • https://poojaindiangrill.com/nbloom/fckuploads/file/46938971110.pdfIn PDF document text
    • http://wrhs1967.org/clients/6/61/617565fc8afb9cc6d18abf932d248b7a/File/72193718203.pdfIn PDF document text
    • https://prikolnaya.com/wp-content/plugins/super-forms/uploads/php/files/b431b2b8518cc18351ec24854268122c/xepofona.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f7480546050---48196786183.pdfIn PDF document text
    • https://culturasiapamplona.com/guiarte_userfiles/files/pebuz.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/cccg19mt1a1dahjavr4o7s3o54/70547165022.pdfIn PDF document text
    • https://wagaskar.com/media/jinepapomidumisekotuwuru.pdfIn PDF document text
    • https://www.hontoys.com.au/wp-content/plugins/super-forms/uploads/php/files/dsclrvhn7elkhbb8hevsmnkbg1/fanepanuradoloxutid.pdfIn PDF document text
    • https://studio45.live/wp-content/plugins/super-forms/uploads/php/files/uar83ff71hj4ild27biejj7ssb/rufuduxemoxeretimuxafo.pdfIn PDF document text
    • https://okna-kursk.ru/page_edit/_samples/userfiles/files/70593483931.pdfIn PDF document text
    • http://artmetinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b194143534---puturejowuvajufetawili.pdfIn PDF document text
    • https://forexinc.ca/upload/editor/file/toxibodakex.pdfIn PDF document text
    • http://alexhofford.com/temp/files/file/bibexugenejodudupa.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fa755a1d0d---22389984615.pdfIn PDF document text
    • http://aleeblog.com/wp-content/plugins/super-forms/uploads/php/files/bejaleftcp32sibhv40bnlpuh1/2994539850.pdfIn PDF document text
    • https://polskieplytki.com/wp-content/plugins/super-forms/uploads/php/files/fc5c8a568191a0bb8eb7409333be4d9a/tokanawesuxitek.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=zirai+m%C3%BCcadele+teknik+talimatlar%C4%B1+cilt+2+pdfPDF link annotation
    • 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_off0000e08c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE08C 10904 bytes
SHA-256: 165183ca2089eb1688c6c276b5aae253b6dbd279d861c43b8d9926bf17c29a5e
font_01_sfnt_off0000f9b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9B3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000111c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111C5 18844 bytes
SHA-256: 16b662188b7d347e459526b7aac2eccc8f6d7f713f9fad851a55c385ac6ba817