Malicious PDF — malware analysis report

Static analysis result for SHA-256 cff9bec174bde999…

MALICIOUS

PDF

84.9 KB Created: 2021-08-22 02:13:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 6a81c3a2c7cc4bedcf36b7e0f03f6e34 SHA-1: f124b7fabf6972b79c47ae222f615c3ce7e5e169 SHA-256: cff9bec174bde9991b69e730f59dcee2067fd3984853e9185fc20f20b29a9395
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution through these links. The document body is heavily obfuscated and does not provide readable content, but the heuristic firings clearly identify the link farm nature of the PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://exima.kr/userData/board/file/73397289488.pdf In PDF document text
    • http://www.alexgis.com/siteuploads/editorimg/file/95657923754.pdfIn PDF document text
    • http://grandviewcommunity.com/userimages/mopojetesefifejoxo.pdfIn PDF document text
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160901728326c8---25989581762.pdfIn PDF document text
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/66857a9dd010cfd3250a0f8bbf1a1b08/rebutemiw.pdfIn PDF document text
    • https://protradingindia.net/userfiles/file/wenopeloligezowinuru.pdfIn PDF document text
    • http://ricarda-allegra.de/userfiles/file/nodiw.pdfIn PDF document text
    • http://laptopplus.be/app/webroot/files/userfiles/files/83266003387.pdfIn PDF document text
    • https://www.acetechnology.co.in/wp-content/plugins/super-forms/uploads/php/files/1016fj76ncj0aed2bldi1tv4sl/10948209901.pdfIn PDF document text
    • http://wksystems.net/HotelEstimator/userfiles/file/15506222619.pdfIn PDF document text
    • https://petroblend.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c7636cf8a2---zipese.pdfIn PDF document text
    • https://lakeshoresmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/bqs3cev6s3taqk8meb8ejtgf90/tijumixatapazemam.pdfIn PDF document text
    • http://alemotta.com/resources/original/file/verawajoj.pdfIn PDF document text
    • https://eecpowerindia.com/codelibrary/ckeditor/ckfinder/userfiles/files/83233957226.pdfIn PDF document text
    • http://f-okinawa.com/img/tmp/files/xibutak.pdfIn PDF document text
    • https://borderpak.com/wp-content/plugins/super-forms/uploads/php/files/a158795365a2bbfdd9ce0678dcd60d4e/zinuxumelafukerijukaj.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16098b7b455494---12818412152.pdfIn PDF document text
    • https://imagebeaute.fr/userfiles/file/xorufuzuvu.pdfIn PDF document text
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076ced5a243f---bezukisadekizu.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609b843051b13---vugoto.pdfIn PDF document text
    • http://chothuethietbi.info/img/files/80215469869.pdfIn PDF document text
    • http://adabaskimerkezi.com/upload/file/99774039948.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=folletos+de+animales+en+peligro+de+extinci%C3%B3n+en+inglesPDF 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_off0000e312.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE312 18040 bytes
SHA-256: 04c31c65a64343b7d66c6b92b1fc9c65c7bec77c6588f60353083d1993392240
font_01_sfnt_off000110dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110DC 11072 bytes
SHA-256: 696d87f0da2dd36e46c2dc65b863dfeb9ec7c91cba2297912555ba2c5b580c2e
font_02_sfnt_off00012a30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A30 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1