Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac255428172f51ba…

MALICIOUS

PDF

100.4 KB Created: 2021-09-01 06:27:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: c3b8af7f8bb87216b145fa240d813b7d SHA-1: 6097a866b9f87008a89ca90640d0d2a77b53224c SHA-256: ac255428172f51bab96b91ad711e9cf9ac11f42278b2336e59e4424c740a9cef
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of external links, many pointing to compromised WordPress sites and disposable hosting, indicating a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for SEO manipulation or to host phishing content. While no scripts were explicitly extracted, the PDF structure and link farm heuristics are sufficient to infer a malicious purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

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://sherylrobphotos.com/clients/56056/File/dizerurogub.pdf In PDF document text
    • https://acornschoolcharleston.org/wp-content/plugins/super-forms/uploads/php/files/366ab55856a10fa94dc53c0381e518c7/77470347633.pdfIn PDF document text
    • https://bookatowncar.com/userfiles/file/51521956583.pdfIn PDF document text
    • https://www.ikedatosou.com/wp-content/plugins/formcraft/file-upload/server/content/files/16095c5165e071---dekagepasijifobuwap.pdfIn PDF document text
    • http://www.gcsystem.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1609c7c0845ee4---90576839362.pdfIn PDF document text
    • http://driscollandgibson.com/images/edit_images/file/38750553362.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16096d7446e8df---dipitebowobitubata.pdfIn PDF document text
    • https://feldmann-spedition.de/pics/userfiles/file/16760562218.pdfIn PDF document text
    • http://tropo-design.com/ckfinder/userfiles/files/suvebumujevivowaberevizif.pdfIn PDF document text
    • http://hferrynetworks.com/FileData/ckfinder/files/20210723_2D35CCC2D9FB1541.pdfIn PDF document text
    • https://laihouston.com/wp-content/plugins/super-forms/uploads/php/files/db1ea769121a966abbe9d61809ea1219/49565302830.pdfIn PDF document text
    • http://holidayinntorino.com/userfiles/files/38594454039.pdfIn PDF document text
    • http://colafranceschi.it/userfiles/files/runodikugawilasakitirowi.pdfIn PDF document text
    • https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/160718724cdbdd---sukem.pdfIn PDF document text
    • https://www.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/1611b60735586a---86768856541.pdfIn PDF document text
    • http://www.deopendeur.org/imgUser/file/85291105875.pdfIn PDF document text
    • https://jjmassociates.com/wp-content/plugins/super-forms/uploads/php/files/f6090a5c40612a38f374b6d4f6112939/sumupaxerabalefojusugoru.pdfIn PDF document text
    • http://k3projekt.pl/uploads/userfiles/files/wodevolexefizu.pdfIn PDF document text
    • http://vagtteam.dk/userfiles/Files/5843432138.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/160da8c523e5ef---zavigalivanabagurejaj.pdfIn PDF document text
    • http://sendedianqi.com/upload_fck/file/2021-6-23/20210623040805721463.pdfIn PDF document text
    • http://www.cemeba.com/uploads/ckfinder/files/19843492829.pdfIn PDF document text
    • http://www.naturhalles.fr/fckeditor/userfiles/file/32938732258.pdfIn PDF document text
    • http://stylist.in.ua/wp-content/plugins/formcraft/file-upload/server/content/files/160984fa76f256---wopamakewufexabo.pdfIn PDF document text
    • http://totaleclipsenv.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af5934ebbf0---puvulonedelejeluv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=electronic+numerical+integrator+and+computer+was+developed+inPDF 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://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_off0001223e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1223E 11092 bytes
SHA-256: bd5b97bfa8f6b7fc8b198a2471c65d326bd1f22d249aec5aa58fe0e42f1550d5
font_01_sfnt_off00013be8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13BE8 18132 bytes
SHA-256: 291df40127828e16057827817bff75cd7f374e52d7a3383f189cb2d239688cf1
font_02_sfnt_off00016aee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16AEE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1