Malicious PDF — malware analysis report

Static analysis result for SHA-256 79a10ae8dcbffc9e…

MALICIOUS

PDF

74.6 KB Created: 2021-06-25 01:27:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 9e36c58b24ae3bf6f90d0cf4af2b3e24 SHA-1: ceffd989966f44e5d45ac0004c46f7d24875035d SHA-256: 79a10ae8dcbffc9e4cea59309c9d73f38270f7385869c3e033cb61890d3ebaef
156 Risk Score

Malware Insights

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

The sample was identified as malicious by a ClamAV detection and an ML classifier. It functions as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to lure users to malicious sites. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, which is unusual for a typical user-facing document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/f7ef6abe969da182834a4c924a0a2486/5809997074.pdf In PDF document text
    • https://www.verpoort-bouw.be/wp-content/plugins/formcraft/file-upload/server/content/files/160a6e34fb01a0---65561703829.pdfIn PDF document text
    • http://timelessmebel.ru/wp-content/plugins/super-forms/uploads/php/files/d374826ad3f5059e156ade12b25dbde1/tukepezivukawidaditelokul.pdfIn PDF document text
    • http://sugarfree-gelato.com/upload/file/gaxaxubeti.pdfIn PDF document text
    • http://adaviestransportltd.com/userfiles/file/lewusokoroladaperedefibif.pdfIn PDF document text
    • https://chmelo.hu/sites/default/files/file/dukobewi.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/2440e14298d37df4ab172c05c3f0178d/matonigalorekiletixasesax.pdfIn PDF document text
    • http://aarogyamedico.com/userfiles/file/vimokimawiv.pdfIn PDF document text
    • https://plasy.com/uploads/file/45292605367.pdfIn PDF document text
    • http://funperm.ru/content/file/83918082656.pdfIn PDF document text
    • http://gsoam.ge/wp-content/plugins/formcraft/file-upload/server/content/files/160c51c06164af---99558989690.pdfIn PDF document text
    • https://www.nordatec.com/wp-content/plugins/super-forms/uploads/php/files/ftdnofq7bcobcc4vlk84i15mff/bemorotimisunitex.pdfIn PDF document text
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ad3fa568196---61972096403.pdfIn PDF document text
    • http://www.redactordecontenidos.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160766e78915a2---90300922935.pdfIn PDF document text
    • https://www.siemers-deutschmann.de/wp-content/plugins/super-forms/uploads/php/files/u8ooe2hfftemrtk3p1nq34cipf/60570634379.pdfIn PDF document text
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/1cdb70bc7ab9733f4d760c45150d5925/1066019799.pdfIn PDF document text
    • https://grand-forge.ru/wp-content/plugins/super-forms/uploads/php/files/a807ffa2c73da1f6dd74bcfd041564b0/23123788870.pdfIn PDF document text
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b945ccb1e66---35936356396.pdfIn PDF document text
    • https://zzhqhi.com/d/files/1213972385.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bd3b4ed98b4---dudago.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/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=how+to+check+size+of+pdfPDF 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_off0000e45a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE45A 5072 bytes
SHA-256: f8c7b237802149c070bb8d2ac8d98015eca16e77c056851dc18bca7514b8cd2b
font_01_sfnt_off0000f5c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5C0 11928 bytes
SHA-256: 9c1abebdafdd45403d90709fc369ffdbb59d91c30a50361f276ad7f1e8fc54b4