Malicious PDF — malware analysis report

Static analysis result for SHA-256 c106ab6b3aefe0c8…

MALICIOUS

PDF

69.8 KB Created: 2021-06-01 11:30:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: b3a508ac6d1b6ea237c4ad122308d9a9 SHA-1: 87a8151cac3f0bb0bf75fccc52281c1ee495b145 SHA-256: c106ab6b3aefe0c8dff00fc43326ad70a5edb8680aa404cb16b52de5908d6b16
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ClamAV as a phishing trojan and by an ML classifier, indicating malicious intent. It contains numerous links, many pointing to compromised CMS upload directories, suggesting it's used as a link farm for SEO manipulation or to host further malicious content. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, but the primary threat lies in the external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://daaeportrett.no/upload/file/kegar.pdf In PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088ca24df82e---rafiz.pdfIn PDF document text
    • http://www.nationaalgolfcongres.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a3bd9435462---39403621775.pdfIn PDF document text
    • https://www.c2commercial.com/wp-content/plugins/super-forms/uploads/php/files/30a469aafbebc8000db498e8ae14dafc/3734997339.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076d0aa5a75f---65723474094.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16093ae528639d---96415529358.pdfIn PDF document text
    • https://www.demetagras.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072205d17528---16336441939.pdfIn PDF document text
    • https://nowackleverkusen.de/wp-content/plugins/formcraft/file-upload/server/content/files/16076403b65a01---72368970449.pdfIn PDF document text
    • http://phuocthuan.vn/images/pic/file/kajedanowapaxo.pdfIn PDF document text
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/f8ace3a3bc86bbe5510eabbdebca8000/12024052221.pdfIn PDF document text
    • http://cleannshieldflorida.com/wp-content/plugins/super-forms/uploads/php/files/10c93ee910d69edff3aa246b13513be3/9102382684.pdfIn PDF document text
    • http://frederickfollows.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1608583d0998ef---febanuvitoteropezov.pdfIn PDF document text
    • https://www.cpro.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160815c7c36de5---nuxejozuser.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=how+to+set+minutes+on+farberware+pressure+cookerPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d3d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3D4 5388 bytes
SHA-256: 504c321548fe71eca4f1cefce99d215e10d910ae00ceeab474b8e0f0b3533a9b
font_01_sfnt_off0000e61c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE61C 10628 bytes
SHA-256: 30d29517b8bbc4d367b98696c962735a9350cfd60c59a97b4c8fb1208d430107