Malicious PDF — malware analysis report

Static analysis result for SHA-256 f766ccf8cb37eae2…

MALICIOUS

PDF

75.6 KB Created: 2021-06-07 13:59:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 5ee672a1ebe099c2c11aadb9cb527a93 SHA-1: ba06afc7e703a3f487cd4437f2e517bc76bee2b4 SHA-256: f766ccf8cb37eae2ab66f8e52171a2dbb9158d5f5c1622108463ef1630dac15c
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised WordPress upload directories, suggesting it's part of a link farm or phishing campaign. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and a URL that appears to be a redirector with a 'utm_term' parameter, further supporting the lure-based attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://smidgel.ru/uplcv?utm_term=how+to+identify+ones+tens+hundreds PDF link annotation
    • http://www.esthemed.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160b3761781b9a---97639106543.pdfIn PDF document text
    • http://shuswapladystriders.ca/userfiles/file/49987790172.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607d00e6a6a61---62617083243.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac4c3623d69---dokip.pdfIn PDF document text
    • http://www.naturapreserved.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9f378681b3---koroxalalepevogu.pdfIn PDF document text
    • https://sieompaysdebray.fr/lesiom/txt/imgadmin/file/vunurabotepuzu.pdfIn PDF document text
    • https://smartcirclegroup.com/userfiles/file/takumonol.pdfIn PDF document text
    • http://www.ausafrica.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160a4eeab57d5d---suginuguruxivasiwixapu.pdfIn PDF document text
    • http://brooklinehs1964.com/clients/6/6a/6a3559cec3eb17f551da2d864c8c85ab/File/zuvotikixutumemok.pdfIn PDF document text
    • http://www.alex-vasilkov.ru/images/wisdom/file/99516489927.pdfIn PDF document text
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1609843369be97---6882003691.pdfIn PDF document text
    • https://travolution.travel/wp-content/plugins/super-forms/uploads/php/files/39321ba367384e17b3f39afbb6d7e6a4/68953508665.pdfIn PDF document text
    • http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a3686b0580e---63537042998.pdfIn PDF document text
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ae53d1fea8---lagaduputinizepikosak.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE95 4792 bytes
SHA-256: 48023cea6653ebe996b9978a22fe041e1f0d1ee4c00beebc2e115a6ca953f2d9
font_01_sfnt_off0000eee8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEE8 10828 bytes
SHA-256: 65b76a82b1e25bf3bd286076916464b13eb0ac0ace5162712be1cba4111b9358
font_02_sfnt_off0001133b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1133B 4324 bytes
SHA-256: 05d2457133b820fa77aa358e30e9acfbad3f04c46ced9a37296d9311117db176