Malicious PDF — malware analysis report

Static analysis result for SHA-256 ae4c5aa8c23fcbca…

MALICIOUS

PDF

70.3 KB Created: 2021-06-09 13:15:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-27
MD5: e67db3b5117866b0598dbc03d43d847c SHA-1: dd40bc95f2ba056270825d914269557c85257bb2 SHA-256: ae4c5aa8c23fcbca331fe327d13b06fe8f6cdac8533f18afc0c965530e3a0e90
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, directing users to multiple external URLs, some of which are hosted on compromised WordPress sites. The embedded document body, though heavily obfuscated, contains text related to 'app download' and 'wkhtmltopdf', suggesting a lure for users to download software. The presence of numerous external links points towards an attempt to redirect users to malicious content or phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://medvor.ru/uplcv?utm_term=y2mte+app+download PDF link annotation
    • https://himalayanwanderer.com/himalayan/userfiles/files/18046570820.pdfIn PDF document text
    • http://dichvugiayphep.net/hinhanh_fckeditor/file/junorepalovifejoja.pdfIn PDF document text
    • http://thm-holding.ru/wp-content/plugins/super-forms/uploads/php/files/1239a828207a3c3e92383aa04f6321aa/90457491823.pdfIn PDF document text
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b4ef99497dc---wibutukutefadotoxeji.pdfIn PDF document text
    • http://richfield1962.com/clients/4/47/47516dc9824f3897220912ef171c404f/File/55284977772.pdfIn PDF document text
    • https://siyata.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/160a20be5310a3---mowelal.pdfIn PDF document text
    • https://liniagdanskzydowo.pl/files/dutidevoz.pdfIn PDF document text
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/160b2ba004723b---refotuzuxizulojarovezesi.pdfIn PDF document text
    • http://www.deadclan.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160bd99b1a1837---tuluxezenajobetavatitujef.pdfIn PDF document text
    • https://carstenrath.com/wp-content/plugins/super-forms/uploads/php/files/jrqpue65mt262phgtdeeobtilc/jofowimunero.pdfIn PDF document text
    • https://goactive.hu/wp-content/plugins/super-forms/uploads/php/files/cd71caa788cb35bcdc78446ac8a7930c/99677102427.pdfIn PDF document text
    • https://leo-translate.com.ua/wp-content/plugins/formcraft/file-upload/server/content/files/16078e61fbc430---80695156987.pdfIn PDF document text
    • http://agendatourvietnam.com/hinhanh/file/fenoziwulaza.pdfIn PDF document text
    • http://stopasbestos.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160750f8bcc7fe---pipewawujof.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_off0000cba7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBA7 4756 bytes
SHA-256: a5b9f767d7c10e252a6ebded7a3a46fb5a4b96cf6f87fa83277e7a8090c570e4
font_01_sfnt_off0000dbcd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBCD 10208 bytes
SHA-256: 02df21f4907ba37cc4db7cadab4ef0ad09e117b06e627740a17aca9b5d33d3a8
font_02_sfnt_off0000fea4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEA4 4324 bytes
SHA-256: 4fcfa7c68d76e23b667942a3ac892d2d5d88346478daafc61479ad4df4af3dd3