Malicious PDF — malware analysis report

Static analysis result for SHA-256 4db727849e8ad65d…

MALICIOUS

PDF

80.5 KB Created: 2021-06-09 00:16:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: 30be28dd2f1eb5a4267a2093eb60e030 SHA-1: b1aafdccd09f576168180cdba24469997db8ae4d SHA-256: 4db727849e8ad65d4da96e60e53e080444df6fcfc87bda008f46c02e662e3a92
164 Risk Score

Malware Insights

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

The PDF file is identified as malicious by ML classifiers and ClamAV, indicating it is a phishing or trojan delivery mechanism. It contains numerous embedded URLs pointing to compromised WordPress sites, likely serving as a link farm to distribute malicious content. The document body, though obfuscated, suggests a lure related to 'Cambridge comprehension passages grade 6', aiming to trick users into clicking the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://krisoc.ru/uplcv?utm_term=cambridge+comprehension+passages+grade+6 PDF link annotation
    • https://www.accidentinjuryalbuquerque.com/wp-content/plugins/super-forms/uploads/php/files/215dcebscvkmlrf0hpkbi69juj/noxavosasewatofevasiw.pdfIn PDF document text
    • https://www.eoluk.com/wp-content/plugins/super-forms/uploads/php/files/nsv85g5jlt798m8igcbc7i5koi/nivew.pdfIn PDF document text
    • http://stasta.com/userfiles/file/65658329734.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608009ace73fb---felokimed.pdfIn PDF document text
    • http://fashioncenterpoint.com/wp-content/plugins/super-forms/uploads/php/files/24334411df62d0b98de0fa9edf8f10e1/mizevubawuxiwemunukalivow.pdfIn PDF document text
    • http://www.sparkprototypes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b41c855f39---26474316029.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e71a94c49c---4163974429.pdfIn PDF document text
    • http://www.playerclub.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607658b851a84---mikefavomopipitasadozozo.pdfIn PDF document text
    • https://www.hotwaterfactory.com.au/wp-content/plugins/super-forms/uploads/php/files/6e88d4df394c0ea9f2f1282f9f0b0839/jisukokasupotijunufowepo.pdfIn PDF document text
    • http://pocatellocampfire.com/wp-content/plugins/super-forms/uploads/php/files/d70dgni5n6dqjtu1fkvvu9vk0k/zegavexuxavodugatenafes.pdfIn PDF document text
    • https://gearforfree.com/wp-content/plugins/super-forms/uploads/php/files/c7uco8ietva8o73fq770rumep3/27280594107.pdfIn PDF document text
    • http://videoacceso.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b30cfcc3b1e---jivubokiwota.pdfIn PDF document text
    • https://acornschoolcharleston.org/wp-content/plugins/super-forms/uploads/php/files/8fef22837d85419bb8387915964fb9b1/dasobobugeb.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://sharpspringwww.kinsta.cloud/wp-content/plugins/super-forms/uploads/php/files/f76a9a626fae52d3b25a28e2c9588b02/digusuvivujosibuxis.pdfIn 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_off0000fc14.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC14 5656 bytes
SHA-256: 2b5ffeb07a847daf53f3ec339d368d8e193ec09a6460d34f2f8d7e76b411190b
font_01_sfnt_off00010f15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F15 11096 bytes
SHA-256: d5e989084b7f51131a05fbc6ec006d9bd9e7104c1b288b4a5980ef24610ca965