Malicious PDF — malware analysis report

Static analysis result for SHA-256 51b42dfcf33dbaec…

MALICIOUS

PDF

72.0 KB Created: 2021-06-04 11:15:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 5d0e8686da10bbddc1d1891c3c002925 SHA-1: df12a68f72b815e1f2db472ef8911527cba2f16e SHA-256: 51b42dfcf33dbaeca992d73f3f4a3d771a280f94e7760a2c8b5f92c7e4c7f583
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to distribute malicious content or lead users to phishing sites. The document body, though heavily obfuscated, contains references to 'bitcoin for beginners', aligning with common phishing lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://goref.ru/files/file/90121999837.pdf In PDF document text
    • https://414movement.com/wp-content/plugins/super-forms/uploads/php/files/b62be9fb02d6c5daf5c5887ed3cdd5ef/batakoma.pdfIn PDF document text
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/160724617a0efe---45946877048.pdfIn PDF document text
    • https://www.frankcapassoandsons.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af92cab0396---47818082722.pdfIn PDF document text
    • https://caravanandre.it/wp-content/plugins/super-forms/uploads/php/files/26cb43474f4e0ce35d9b0885da0e0bff/79545031534.pdfIn PDF document text
    • http://pamat.ro/UserFiles/file/7790695213.pdfIn PDF document text
    • https://www.justgym.co.za/wp-content/plugins/super-forms/uploads/php/files/auupctdl0ca91p1n9fgi27k7at/17308388564.pdfIn PDF document text
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609dbd5730377---15834598025.pdfIn PDF document text
    • http://ttlengenharia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a5e181988ce---xajerowixamaweteti.pdfIn PDF document text
    • http://www.majorisinvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16079b71163615---garigovemeveguxaj.pdfIn PDF document text
    • http://artmetinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cbae7f33fa---56123516831.pdfIn PDF document text
    • https://miaousland.fr/ckfinder/userfiles/files/48779583190.pdfIn PDF document text
    • http://www.britocunhaadvocacia.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16078bba729567---4114591026.pdfIn PDF document text
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/6evcfj7dkrt3nfef0i25k3ufak/14741949162.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160719c4b2ba47---58618735561.pdfIn PDF document text
    • https://daaeportrett.no/upload/file/17846253772.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/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=how+to+buy+bitcoin+for+beginnersPDF 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_off0000dc61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC61 5104 bytes
SHA-256: eefd99bc9486ef1b2945e9bae5e419da2db6481861cb33c41d022a69222f97cd
font_01_sfnt_off0000edf0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDF0 10780 bytes
SHA-256: 583b1c16fcb6fdfa9171c8e70cf56adac94b45b121ec872ba87ccb4be6d93f6e