Malicious PDF — malware analysis report

Static analysis result for SHA-256 4137cb09d7628935…

MALICIOUS

PDF

78.8 KB Created: 2021-06-13 14:41:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 0874420dc9968d63c67419169ad65014 SHA-1: a7ab5b339a8dc667b4cf2e40bb0f6b545ecb08c5 SHA-256: 4137cb09d7628935fe7c46fc80d4fb76ae446d602e83749bf249e38bd62b8ef6
156 Risk Score

Malware Insights

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

This PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external links, many hosted on compromised WordPress sites or disposable domains, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create PDF versions of web pages, further supporting the phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://synerhu.ru/uplcv?utm_term=first+aid+guide+horde PDF link annotation
    • http://sushi-belovo.ru/files/15146524231.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160aae43f4446c---lizuzosipaxoru.pdfIn PDF document text
    • https://sgpropertylawyers.com/wp-content/plugins/super-forms/uploads/php/files/69b1c74ca8036a3b5453939c1b40748c/renodemivofu.pdfIn PDF document text
    • https://bilalyapidekorasyon.com/userfiles/file/kuwometofonuful.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160ba0236bea62---75933975312.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/668530af4c956a624d307eb077722949/wugedegabijusodonadutiwa.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160b29b296c46a---67988155260.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088a40310052---lifesuraguwemenekafifig.pdfIn PDF document text
    • https://swimproject.eu/wp-content/plugins/super-forms/uploads/php/files/59d648bcb7591537a46d52b9850b3fcf/tibatatijofijarutake.pdfIn PDF document text
    • http://trainternational.in/wp-content/plugins/formcraft/file-upload/server/content/files/1608c4348dff8a---33458366212.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1609fad7abef43---32065535530.pdfIn PDF document text
    • https://bluetact.com/locktactyuma/userfiles/file/81759843291.pdfIn PDF document text
    • https://yuktiedu.com/wp-content/plugins/super-forms/uploads/php/files/a0dddf8ea73ddf61796b2e27d6876fb5/litosupuderumisosipaturug.pdfIn PDF document text
    • http://sobinco.cz/ckfinder/userfiles/files/34437478628.pdfIn PDF document text
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160803d5db07e5---57871932506.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f81f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF81F 5012 bytes
SHA-256: 97ff971a12ea1462219be11f3ec6b353dc5d8646a5ed864e2a4a70f26fb28c04
font_01_sfnt_off00010926.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10926 10844 bytes
SHA-256: 5ac817f022f3ae04c059d7a9181a6c2c0831e2c0d89e8e908a55fe8ec2c13f55