Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f0fcea35a7681e0…

MALICIOUS

PDF

95.9 KB Created: 2021-06-23 11:50:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-15
MD5: 1e7c509fed897024bdbe7b2da7bed114 SHA-1: b6dc9eed59c41934df18296bff4cba9bfeaa412b SHA-256: 4f0fcea35a7681e00b5259cb683a5de83dabb18364cbf5cf3892311594ede05e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded links, many pointing to compromised WordPress sites, suggesting a phishing or credential harvesting campaign. The document body, though heavily obfuscated, contains metadata related to wkhtmltopdf and Sudoku, likely serving as a lure to disguise the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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 https://kuechentreff-schmid.de/wp-content/plugins/super-forms/uploads/php/files/ml30hepcn9fptahbq7d1715pn3/wanakurubojutijubokog.pdf In PDF document text
    • https://www.femregenx.co.za/wp-content/plugins/super-forms/uploads/php/files/bs2jrsfpeng7gd7eut22ie6d80/28355528479.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c9eea4aa945---92961087631.pdfIn PDF document text
    • https://alfa-pechati.ru/wp-content/plugins/super-forms/uploads/php/files/ef10eadc4897af67b26b9d1b7fe08f06/77858905839.pdfIn PDF document text
    • http://cloverpark1961.com/clients/6/6a/6a73a08bb68f643008adb5efbbb44e43/File/71441090308.pdfIn PDF document text
    • http://llux.vn/uploads/files/bifubulima.pdfIn PDF document text
    • http://cafegreenwichvillage.com/uploads/files/86835484030.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/160704defcc166---wakomopat.pdfIn PDF document text
    • https://unicon-msk.ru/data/files/jujilokuwimofajixo.pdfIn PDF document text
    • http://www.adatechotomasyon.net/wp-content/plugins/formcraft/file-upload/server/content/files/1609b413ed055b---mexipagojuli.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608fd44680b82---fizeragef.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/43af45c1f1e390071e0f8fd7e1be2cab/vedubusagojibidi.pdfIn PDF document text
    • https://www.autodepotperformancegroup.ca/wp-content/plugins/super-forms/uploads/php/files/cirkilesei3sluvdra4opprkk7/zolakewaguwabagufuv.pdfIn PDF document text
    • https://bilbox.es/wp-content/plugins/super-forms/uploads/php/files/311d0d8fc67975f0e58e809c38877009/48670737630.pdfIn PDF document text
    • http://kondicionery-ivanteevka.ru/upload_picture/file/nowatolodejovibalexo.pdfIn PDF document text
    • http://amtusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a3efd87b0ae---gilirijuditeworolava.pdfIn PDF document text
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160c84c1def10f---53980432653.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=sudoku+tricks+pdfPDF 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://scripts.sil.org/OFLIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001105a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1105A 5072 bytes
SHA-256: cd7a24e799e6fe2c6d7f56c4aa2e02505e0a464a21beffd4d6bc12beec772384
font_01_sfnt_off000121ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121AC 4468 bytes
SHA-256: d3ac616db70d2b9cc8985edc2273f8a4bd3669273d22ea580cd40f4a2629bf43
font_02_sfnt_off0001325d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1325D 12320 bytes
SHA-256: dece76c6cb772c03873f71a19b1cca6d2744d9d15105d57d4e7b73a0ff3b27ba
font_03_sfnt_off00015cbf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15CBF 16344 bytes
SHA-256: b6060cfb0c71483a602f73ccf1b193ec6b7f1cdd3443a948b4b104c2cf3cddc2

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