Malicious PDF — malware analysis report

Static analysis result for SHA-256 91d66a7658e618a2…

MALICIOUS

PDF

80.5 KB Created: 2021-09-05 08:33:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: ded329f6ea17845550253f9a2ffb2bbd SHA-1: 30ea48d5e9e96076df23af672b791f220c916541 SHA-256: 91d66a7658e618a2deed5c7f502efe857b82f3092a605802e40b7108b10aca05
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple URLs hosted on potentially compromised CMS uploads. The presence of numerous unknown URLs suggests an attempt to distribute further malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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://www.travelticket.com.au/wp-content/plugins/super-forms/uploads/php/files/0jb7l2j6oof9p1uptnn4ugv8sd/vimexilezukudogi.pdf In PDF document text
    • http://files.ibiza-ferien.de/file/70552225039.pdfIn PDF document text
    • https://calldidocta.com/wp-content/plugins/super-forms/uploads/php/files/d91146e680fe071985c867a18986b2cf/85036071797.pdfIn PDF document text
    • http://pravkniga.ru/files/userfiles/files/36964575969.pdfIn PDF document text
    • https://perfecthospitals.org/ckfinder/userfiles/files/galojevav.pdfIn PDF document text
    • http://pocatellocampfire.com/wp-content/plugins/super-forms/uploads/php/files/4bl3upqt6ai2rc81r61f8koffu/kifigajonavurij.pdfIn PDF document text
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16121900bb8ed5---musuxepe.pdfIn PDF document text
    • http://standartbio.com/fckfiles/file/vuvekejapu.pdfIn PDF document text
    • https://kingdomofgodmn.org/userfiles/files/55254169513.pdfIn PDF document text
    • https://africanresearchcenter.com/userfiles/file/35202320888.pdfIn PDF document text
    • http://raunlarose.us/wp-content/plugins/formcraft/file-upload/server/content/files/160984ce66c1d4---19791240073.pdfIn PDF document text
    • http://rexant.by/upload/editor/files/jaliririmixoz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=american+sign+language+worksheets+pdfPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d522.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD522 17932 bytes
SHA-256: 938427fe02244a965c1f9eeb5bec3eedcf38c09eb5a2bb27ada46a7fdc7db061
font_01_sfnt_off00010326.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10326 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011b3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B3D 11328 bytes
SHA-256: 456a9e5bf849e0ca95718050e2590c599e65da0a09e0ee02b88284030a1b8b32

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