Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3bbfeac8559bb6c…

MALICIOUS

PDF

78.7 KB Created: 2021-09-09 23:18:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4546080498bd0b927129fba9d80d7c25 SHA-1: 7fbea224dbbe2451f6d4d4b092b1974d1c39db7d SHA-256: a3bbfeac8559bb6c929198294d01e59eb18ad667cb4254effcd340e4be0e3bc1
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to PDF files hosted on various domains, some of which appear to be compromised CMS uploads. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://signauction.net/userfiles/file/xutozazuf.pdf In PDF document text
    • http://tubesealer.com/uploaded/file/337428097612fafa8874ca.pdfIn PDF document text
    • http://culbertsonlawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/79671506243.pdfIn PDF document text
    • http://tokyo-sanritsu.com/userfiles/file/daleg.pdfIn PDF document text
    • https://www.iieng.org/editor/ckfinder/userfiles/files/2399903155.pdfIn PDF document text
    • http://gugugroup.com/userfiles/foleximojopokig.pdfIn PDF document text
    • https://ptogel2.com/contents/files/mituxevexujuju.pdfIn PDF document text
    • https://bwhe.in/ckfinder/userfiles/files/73194413470.pdfIn PDF document text
    • http://saltokisport.com/uploads/files/sukid.pdfIn PDF document text
    • https://cms.blauraum.com/wp-content/plugins/super-forms/uploads/php/files/52f582b6d9616cf54912efe274aa7e6c/witivuzoku.pdfIn PDF document text
    • https://www.ediliziaindustriale.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133132571fab---91444207225.pdfIn PDF document text
    • http://graphicon.hu/wp-content/plugins/formcraft/file-upload/server/content/files/16133b95fd8e41---gojakagebixevitene.pdfIn PDF document text
    • https://www.autopsrus.com/ckfinder/userfiles/files/580322788.pdfIn PDF document text
    • https://fitness-sport.it/userfiles/file/58544229341.pdfIn PDF document text
    • https://pelicanfinancialnetwork.com/ckfinder/userfiles/files/82423406383.pdfIn PDF document text
    • http://abnigakgdsg.friendship-match.com/upload/files/20847272791.pdfIn PDF document text
    • http://rem-stroymont.ru/img/file/pikivubimetitoseb.pdfIn PDF document text
    • https://asiastudy.in/ckfinder/userfiles/files/warimos.pdfIn PDF document text
    • http://kino-cosmik.ru/sadm_files/kibelopodanixudulu.pdfIn PDF document text
    • https://cairparavel.ro/app/webroot/files/userfiles/files/bodotosunotulugoxabux.pdfIn PDF document text
    • https://aymexco.ro/ckfinder/userfiles/files/95553988534.pdfIn PDF document text
    • http://rhondachem.com/d/files/32832152308.pdfIn PDF document text
    • https://transturist.ba/ckeditor/ckfinder/files/files/voweropin.pdfIn PDF document text
    • http://www.omt.ntou.edu.tw/ckfinder/userfiles/files/pepebamitelelax.pdfIn PDF document text
    • https://kvartira-zalog.ru/wp-content/plugins/super-forms/uploads/php/files/24c9313ec8f79dffe773b505b0c0fa7f/tiweponefeku.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=wwe+2k18+ppsspp+downloadPDF 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_off0000ce15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE15 10648 bytes
SHA-256: fce5d0d5fedaa3c2495e58fd03f79ec1d2c933560204ee9714bd3eca864e71ca
font_01_sfnt_off0000e6c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6C1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fed3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFED3 17904 bytes
SHA-256: a78724221806144eb720dc1cf6a91ac2192b66771924c8f168413c1ef7022790

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