Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7b81978fc35c9d5…

MALICIOUS

PDF

71.5 KB Created: 2021-06-20 00:20:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: b5b82d60cab6196464190fade537ab33 SHA-1: 0d5b5166cd8396c6b32df60962a2932b7c3bced2 SHA-256: a7b81978fc35c9d569136919f3d9b78bdf20094f905539e943574627b76982e2
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Heuristics identified the document as a link farm, with numerous URLs pointing to compromised WordPress sites and disposable hosting. The embedded content, though heavily obfuscated, suggests an attempt to disguise the malicious nature of the links.

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=unicorn+jokes+dirty PDF link annotation
    • https://autosofortkauf.ch/wp-content/plugins/super-forms/uploads/php/files/e8auoe3dqgtdg9jcfj4657o0u4/wegalivu.pdfIn PDF document text
    • https://namastehealth.in/wp-content/plugins/super-forms/uploads/php/files/oej0mh0kagftuqjq3r6cl6tvat/52273659057.pdfIn PDF document text
    • https://rhythmcprandfirstaid.com/wp-content/plugins/super-forms/uploads/php/files/fc8211898ff3147786859dec48ac0818/pujederikova.pdfIn PDF document text
    • http://polloricowings.com/uploads/files/37031798688.pdfIn PDF document text
    • https://www.baptistenhardenberg.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160733254f21d0---kodor.pdfIn PDF document text
    • http://brandweeramsterdamamstellanden.nl/userfiles/file/42796002631.pdfIn PDF document text
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/160929a2bca3fc---gifegososiwadawadofewaxo.pdfIn PDF document text
    • https://www.inkfactory.pk/wp-content/plugins/formcraft/file-upload/server/content/files/160c9a02468952---kakipovuzefewopu.pdfIn PDF document text
    • http://cartonwrappingmachine.com/userfiles/file/zaxopusumawukowameraxe.pdfIn PDF document text
    • http://vytvarnyobchod.cz/UserFiles/File/lusonarod.pdfIn PDF document text
    • https://www.auditek.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1607a018d5edd5---59794472300.pdfIn PDF document text
    • https://houstoncoinshow.org/FCKeditor/file/rewidepelevutesekalo.pdfIn PDF document text
    • https://dmddsgn.com/wp-content/plugins/super-forms/uploads/php/files/009baa0c47abde984ee9be2ce026e208/80791384766.pdfIn PDF document text
    • http://espacioschillout.es/images/admin/file/wovukiduvisabazetoxug.pdfIn PDF document text
    • http://www.sunarozlem.com.tr/wp-content/plugins/super-forms/uploads/php/files/ouvnfmh32e1p08d1vd1dcs2ef5/46979006895.pdfIn PDF document text
    • https://ncfouting.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa21e6c43e3---jidovodozo.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_off0000db93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB93 4924 bytes
SHA-256: 747c06411d32e85df76c783d254bd4aacd222866f76985b4e25c86cbcaa7b763
font_01_sfnt_off0000ec76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC76 10960 bytes
SHA-256: 3f31f3a68a6fb34b2844b238b607e480bfbb93601938246621fbd899c950c60b