Malicious PDF — malware analysis report

Static analysis result for SHA-256 85198af158259d6b…

MALICIOUS

PDF

76.6 KB Created: 2021-09-06 14:07:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c52bb5a3ae68c8aeafa44ecff264d47d SHA-1: d5d6b9d25931a0b770fc5c0ed8c0a1a3a276c54b SHA-256: 85198af158259d6be6affda8331c426f8d2d7bda00dc9de6cc3cfcec062e96e6
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a link farm pointing to numerous compromised WordPress sites, suggesting it's designed to redirect users to malicious content. The ML classifier strongly indicates maliciousness, and the heuristics identify it as a link farm on disposable hosting, likely serving as a lure for phishing or malware downloads. No scripts were extracted, but the embedded URLs are the primary indicators of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 5

  • 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=machzor+online+pdf PDF link annotation
    • http://aftckwt.com/uploads/file/4335976190.pdfIn PDF document text
    • https://www.intermediastudios.com.mx/wp-content/plugins/super-forms/uploads/php/files/2cf157c90215455373dbb148f0f95532/5331612812.pdfIn PDF document text
    • https://frennphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f9c17f83bfa---lojowenasumifobalud.pdfIn PDF document text
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/4ff07472bb2b5bca381dded4356aee7f/fekikademelusikomupewuka.pdfIn PDF document text
    • http://kiuruvedenlukio.fi/tiedostot/file/48105318588.pdfIn PDF document text
    • https://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/4q5tfqp6tk1k2l9b2p1d43i7u3/26310612449.pdfIn PDF document text
    • https://encouragingmath.com/wp-content/plugins/super-forms/uploads/php/files/8f9139fa8d59f93a0f0a52e6aa09c53d/xugabutizituvisoborabi.pdfIn PDF document text
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160d812ba774f7---38549409112.pdfIn PDF document text
    • https://www.heainc.com/wp-content/plugins/formcraft/file-upload/server/content/files/160946f74c37ff---73798643362.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/160714cceee0f2---84668837904.pdfIn PDF document text
    • https://xuantruongtech.com/images/ckeditor/files/4410900400.pdfIn PDF document text
    • http://asid.rw/userfiles/file/40971502791.pdfIn PDF document text
    • http://hieuchuan.com/upload/files/22060803382.pdfIn PDF document text
    • http://robertfeinberglaw.com/images/edit_images/file/97233169014.pdfIn PDF document text
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c1e051ee1ec---kerex.pdfIn PDF document text
    • http://ypperfect.com/ckfinder/userfiles/files/9480920275.pdfIn PDF document text
    • http://aucoindeshalles.com/menu/file/62128112276.pdfIn PDF document text
    • https://buddingheights.org/wp-content/plugins/formcraft/file-upload/server/content/files/1611520650dbe8---maruwedezok.pdfIn PDF document text
    • https://ruta.hu/ckfinder/userfiles/files/nefalojidofonowakuv.pdfIn PDF document text
    • https://nam.it/wp-content/plugins/formcraft/file-upload/server/content/files/16076201d863f7---12570448691.pdfIn PDF document text
    • https://pristineleather.com/userfiles/file/23361136474.pdfIn PDF document text
    • http://anhuizhkj.com/upload_fck/file/2021-5-7/20210507092439489431.pdfIn PDF document text
    • https://fitnessrev.net/wp-content/plugins/super-forms/uploads/php/files/ejo0akisebrf09hfrn5grnk1ie/lorubaj.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c65c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC65C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000de6e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE6E 18028 bytes
SHA-256: 4fb0e777c73eee413edd72e7e70a95cb6bab53a3dd8d59b094191c03309804c5
font_02_sfnt_off00010dd3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DD3 10504 bytes
SHA-256: 8feb63e27e2f45e2505ba89e5a9fdcfebc87fafb0d7c9a41c3d9dd6a6d44dbcf