Malicious PDF — malware analysis report

Static analysis result for SHA-256 3b42cd46b0d87ab6…

MALICIOUS

PDF

81.8 KB Created: 2021-09-18 16:06:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: a81166a2e5af80d48e5c3620d33c33bd SHA-1: 12b51bc0014b54272b8d70d5525be9f43780285f SHA-256: 3b42cd46b0d87ab66264bbba45bc7a571cb46ac9205fed074c6438c4a85ce7e2
196 Risk Score

Malware Insights

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

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains a 'browser extension / update installation lure' heuristic, indicating a social engineering attempt to trick the user. The document body is heavily obfuscated, but the presence of numerous URLs, many hosted on compromised WordPress sites or disposable domains, suggests a link farm designed to redirect users to malicious sites. One URL, http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e5b636f259---77341784151.pdf, is specifically flagged as a compromised CMS upload. While no scripts were directly extracted, the overall structure and heuristics point towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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://schokozentrale.de/idata/91797688034.pdf In PDF document text
    • http://abovomedia.hu/_user/file/49893526306.pdfIn PDF document text
    • http://envisystem.com/upload/userfile/files/wifuzekosovotisegugu.pdfIn PDF document text
    • http://jualumnitoronto.com/editor/uploadfiles/sozoxa.pdfIn PDF document text
    • https://girisimhaber.com/uploads/file/3918057363.pdfIn PDF document text
    • http://kartelabasligi.com/images_upload/files/jawumozofabezugurekoju.pdfIn PDF document text
    • https://yogaspotny.com/userfiles/file/doxateximizafu.pdfIn PDF document text
    • http://zbraneklapka.cz/ckfinder/userfiles/files/komolugevapobizamix.pdfIn PDF document text
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e5b636f259---77341784151.pdfIn PDF document text
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16141c49375926---dodezitur.pdfIn PDF document text
    • http://madurastones.com/userfiles/file/50522460718.pdfIn PDF document text
    • http://informerfitness.com/wp-content/plugins/super-forms/uploads/php/files/9a547ddc9d831454030e1fb91734fa99/keniraf.pdfIn PDF document text
    • http://elistaprezentow.pl/userfiles/file/52741248987.pdfIn PDF document text
    • http://wefocusdesign.com/upload/files/19896323081.pdfIn PDF document text
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/1c5f437d6eebee3d1d9d76a34927b37a/raruzetopum.pdfIn PDF document text
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1614090d158498---57213852622.pdfIn PDF document text
    • http://www.alliance-bio.com/user_data/editor/ckfinder/core/connector/php/upload/files/64540706034.pdfIn PDF document text
    • http://jsushibrea.com/uploads/files/90313220266.pdfIn PDF document text
    • http://unicorn-furnitures.com/d/files/zemupidejigudo.pdfIn PDF document text
    • http://portalcom-b2b.es/img/user//file/_0482548001630728961.pdfIn PDF document text
    • http://techcessgroups.com/userfiles/file/64767044923.pdfIn PDF document text
    • https://tinnituskozpont.hu/files/63704239152.pdfIn PDF document text
    • http://bjhtdszdh.com/v15/Upload/file/20219823994249.pdfIn PDF document text
    • http://dhleisure.com/ckupload/files/runotuxuwiwefavovotugoret.pdfIn PDF document text
    • https://gulfb2b.com/userfiles/file/pibusanekelumolife.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=norsk+to+englishPDF 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_off0000d954.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD954 10296 bytes
SHA-256: 1ef3f0c76cd83c0a1a6c4c0d029f9a7ea5ab698c9f5d7c6f6a7437217dc34e53
font_01_sfnt_off0000f06b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF06B 18816 bytes
SHA-256: c166faa3d93da2eea597b7919432950bd7977c863c7dcbf3874b40e9a0e9c84f
font_02_sfnt_off00012191.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12191 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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