Malicious PDF — malware analysis report

Static analysis result for SHA-256 ca8ce9c4ff2e01a2…

MALICIOUS

PDF

77.7 KB Created: 2021-09-17 19:28:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 82b98887c2018a58be03744fbe640db2 SHA-1: 16e5d5b312f5ad3ebc5346bf862bb39adb9cb5c2 SHA-256: ca8ce9c4ff2e01a20505160f905ee1247a9da1d28ffaf1cd506669a66515acbb
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to compromised WordPress upload storage and other disposable hosting sites, disguised with terms like 'home buying offer letter'. The embedded URLs and link farm structure strongly suggest an intent to redirect users to malicious sites for phishing or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://kossuthdigisuli.hu/userfiles/file/99478602540.pdf In PDF document text
    • http://micronforgacsolo.hu/UserFiles/file/labamodoxuputijibaset.pdfIn PDF document text
    • http://eortak.com/img/fck_temp/file/vunexomidoj.pdfIn PDF document text
    • http://lagostena.it/userfiles/files/95075976726.pdfIn PDF document text
    • https://samsungklima.net/upload/ckfinder/files/58559589227.pdfIn PDF document text
    • http://nissanotogovap.vn/uploads/images/files/gisuzerubepajotimodoraro.pdfIn PDF document text
    • https://wronba.pl/uploads/wysiwyg/file/woxufinorukivo.pdfIn PDF document text
    • http://ride-on-earth.com/images/blog/file/73889900154.pdfIn PDF document text
    • http://godsownproperties.com/userfiles/file/poxotonokirelenebesogek.pdfIn PDF document text
    • http://ideviceplus.be/app/webroot/files/userfiles/files/57834593261.pdfIn PDF document text
    • http://www.introspekta.si/ckfinder/ckeditor_uploaded_files/files/5345829988.pdfIn PDF document text
    • http://www.laterveer-biesenbeek.nl/ckfinder/userfiles/files/51826557379.pdfIn PDF document text
    • http://htwy.com/upload/file/43086607584.pdfIn PDF document text
    • https://projetounificado.com/uploads/files/reseni.pdfIn PDF document text
    • http://hanyangsteel.com/files/fckeditor/file/899900653613c14a5ae0c5.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138ff8c22c34---45892738560.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/161415d7ee599b---niwumonijemifugawasuj.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/s178ln8k0b7urr0v95ef92bri2/jarugoludi.pdfIn PDF document text
    • http://vtvxm.vn/userfiles/file/giguvilakakazajezesor.pdfIn PDF document text
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d03a18039e---viwemitosasorarinapopus.pdfIn PDF document text
    • https://netwindowvn.com/uploads/userfiles/file/ponaz.pdfIn PDF document text
    • https://highlander-inn.com/assets/userfiles/files/76755796034.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=home+buying+offer+letterPDF 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_off0000cc72.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC72 17372 bytes
SHA-256: 0dc2f4b80edb824efac9638734192c9d0b335d28c313048e59f6e6f025e7b5bd
font_01_sfnt_off0000f995.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF995 10572 bytes
SHA-256: 1323292bce348270c3cd2f427f4cc75325ad2bf80d90e697d76c065aa943466d
font_02_sfnt_off000111a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111A8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1